HORTICULTURE
VEGETABLE SCIENCE
(Vegetables, Tubers & Spice Crops)
Breeding of Spice Crops
(Black Pepper, Cardamom, Ginger and Turmeric) K. V. Peter
Kerala Agricultural University, Trichur -680 656 P N Ravindran
Centre for Medicinal plants Research, Kottakal, Kerala K. Nirmal Babu
Indian Institute of Spices Research, Calicut- 673 012 Minoo Divakaran
Providence Women’s College, Calicut -673012
(12.10.2007)
CONTENTS Black Pepper Cardamom Ginger Turmeric Keywords
Area, Production, Trade, Origin, Distribution, Botany, Taxonomy, Systematics, Cytology, Collection, Conservation, Genetic Resources, Cultivar Diversity, Evaluation, Utilization, Crop improvement, Selection, Hybridization, Polyploidy breeding, Mutation breeding, Biotechnological Approaches, Micropropagation, Synthetic seed, Protoplast culture, Genetic transformation, mapping population, Plant regeneration, Molecular characterization
Spices and aromatic plants are mainly used for imparting flavour, aroma, pungency and for seasoning the food. Many of them are also used in medicines and in perfumery. The International Standards Organization (ISO) lists about 112 plant species as spices. India is considered as the magical land of spices. Peninsular India is a rich repository of spices and over 100 species of spices and herbs are grown in about 2 million hectares with an annual production of 2.2 million tonnes and accounts for about 47% of the global trade. Black pepper, cardamom, ginger, turmeric, capsicum, cinnamon, clove, nutmeg, tamarind, and vanilla constitute the major spices.
Seed spices like coriander, cumin, fennel, fenugreek, dill, caraway, anise and herbal spices like saffron, lavender, thyme, oregano, celery, anise, sage and basil are also important. India is the native home of many important spices like black pepper, cardamom, tamarind, curry leaf and to certain extent ginger, turmeric, garcinia and cinnamon where a good variability exists. In fact there is no state in India that does not grow spices, which in turn play an important role for the lives of the people and for their own economic sustainability. From the Indian sub-continent these spices spread over to most of the tropical part of the world.
Black pepper, cardamom, ginger and turmeric are the major tropical spices of the world and cultivated in many countries in wide variety of geographical regions. Each country has its own traditional cultivars/ races/ types of these spices.
Black pepper
Black pepper (Piper nigrum L.), christened as the ‘King of Spices’, is an important agricultural commodity of commerce since time immemorial. It is one of the oldest and most important spices known to man. Black pepper is valued for its characteristic pungency and flavour, as an ingredient in food preparations and also as a condiment. Black pepper is also very important in traditional medicine (Ravindran, 2000).
Area, Production and Trade
The total production of black pepper in the world is around 342,625 tonnes from an area of 583,897 ha as per the estimates of the year 2003. During the same period in India pepper was grown in an area of 225,327 ha and produced around 72,465 tonnes of which 17,787 tonnes was exported. Kerala, Karnataka and Tamil Nadu are the major black pepper producing states in the country out of which almost 90% is contributed from Kerala. The average pepper productivity in India is one of the lowest in the world (303 kg/ha). The productivity of pepper per vine is highest (1kg) in Karnataka and lowest in Kerala (0.6kg). Demand for black pepper and its products in the world market are increasing at the rate of 3.2% per annum in volume and 8% in value terms.
(Ravindran et al, 2006).
Origin and Distribution
Genus Piper is distributed mainly in Central and South America, accounting for 60% of the species. The rest of the species are found in India, Malaysia, Indonesia, Sri Lanka, China and other Asian Far East Asian countries. But the black pepper, Piper nigrum L, is a native of humid, tropical, moist evergreen forests of Western Ghats of India growing from almost sea level to an elevation of about 1500 m. The northeast and the southwest regions of India are recognized as two independent centres of distribution of the genus Piper.
Fig.1. A field view of Black pepper
Botany, Taxonomy and Systematics
Black pepper is a perennial woody climber, climbs on support trees by means of ivy like roots for flowering and fruiting (Fig 1). Black pepper is a vigorous vine with thick and rough old stem bearing numerous flowering plagiotropic branches. Runner shoots arise from the base. Leaves are of variable shape and size but generally ovate – lanceolate, thick, coreaceous, glabrous with 2 to 3 pairs of lateral ribs. Spike filiform, pendulous with sessile decurrent bracts formed into shallow cup subtending the anthers and gynoecium stamens 2 with dithecous anthers. The carperl is single with spherical ovary. The stigma is 3-5 lobed with no style. The fruit is a drupe, spherical, pungent and red when ripe. Wild forms usually dioecious but most cultivated ones are bisexual. Many cultivated type’s exhibit protogyny with female phase preceding the male phase by few days or weeks (Ravindran et al, 2000).
The first description of pepper and few of the related wild species was made by Van Rheede (1678) in his book ‘Hortus Malabaricus’ (1678). Van Rheede described five types of pepper including the black pepper and long pepper. The major floristic studies of Indian Piper were those of Hooker (1886), Rama Rao (1914), Gamble (1925), Rahiman et al. (1979, 1981) and Ravindran (1990, 1991, 1992 a, b, and 1993), Mathew (1998) and Saji (2006). Ravindran (1991) and Saji (2006) carried out taxonomic and biosystematic studies on Piper taxa occurring in South India and suggested a taxonomic key for the piper species occurring in Western Ghats. The important biosystematical studies carried out in black pepper cultivars as well as Piper spp. were those of Rahiman and Subbaiah (1984), Rahiman and Bhagavan (1985), Ravindran (1991), Ravindran et al. (1994), Ravindran and Nirmal Babu (1996), Sebastian et al. (1996), Sebastian and Sujatha (1996) and Mathew et al. (2001). They used comparative flavanoid analysis, biometrics using D2 statistics, numerical and chemo taxonomic methods, cluster analysis, principal component analysis and isozyme study for determining divergence among species and cultivars. Ravindran (1991) and Ravindran et al. (1997 a, b) reported cluster analysis of 44 major cultivars and seven wild collections of Piper nigrum using 22 characters. This analysis brought out the uniqueness of certain cultivars (such as Panniyur 1, Vadakkan, Kuthiravally, Karimunda) and closeness between certain cultivars (Aimpiriyan – Pulppally, Kalluvally; Poonjaramunda – Thulamundi, Narayakodi – Kuriyalmundi etc.) giving indications of the ancestry of various cultivars. This also indicated that domestication of black pepper from the forest grown wild plant, could have started at many centers isolated in space and time (Ravindran and Nirmal Babu, 1988; Ravindran, 1991, 2000).
Cytology
The cultivated black pepper is having the somatic chromosome number of 2n=52. Various reports indicated the existence of a polyploid series in the genus, Piper, which include 2n=24, 26, 36, 39, 40, 48, 52, 60, 64, 64, 68, 80, 96, 104, 132 and 156. All the species examined from South India were reported to have common basic number of X = 13, while the North Indian species, X = 12 and that X = 13 reported consistently for the genus has to be taken as the valid chromosome number of the genus (Mathew 1958, 1972, Sharma and Bhattacharya 1959, Dasgupta and Datta 1976, Jose and Sharma 1984, Bai and Subramanian 1985, Rahiman and Nair 1985, Nair et al. 1993, Mathew et al. 1998). Most of the species including the polyploids exhibited normal meiotic behaviour suggestive of their alloploid nature. The sparse pairing of chromosomes in the hexaploid P.betle is suggestive of its hybrid origin. The chromosome data available on the genus show that this is chromosomally a homogeneous group. It was also suggested that the various Piper spp. represent a homogeneous assemblage where gene mutation or imperceptible chromosome changes have affected the evolution both at inter and intra specific levels.
Mathew (1958) reported a heteromorphic bivalent in the male plants of P. longum, which he has interpreted as ‘x’ and ‘y’ chromosomes with male having ‘xy’ and female ‘xx’. Nair et al. (1993) found a natural triploid having considerable chromosome number variations, from 2n=52 to 2n=104. Progenies having 2n=55, 65, 72, 73, 76, 82, etc. were found to be very abnormal in growth. From these, they concluded that the triploids could have originated under natural condition by hybridization between 2n=104 and 2n=52 forms, and might have survived well because of the successful vegetative propagation.
Collection and Conservation
Black pepper has originated in the moist evergreen forests of the Western Ghats. Wild populations of Piper nigrum are found extensively distributed in many forest areas. P. nigrum is a tetraploid. It was indicated that P. nigrum might have originated through hybridization between species occurring in Western Ghats. Ravindran (1991) proposed three species viz., P. wightii, P.
galeatum and P. trichostachyon as the putative parents of P. nigrum, based on morphological and biosystematic studies. All these are woody climbers, having more similar to P. nigrum than to those of other species. The fruits of all the three have small amount of pungency and flavour.
Of the three, P. wightii and P. galeatum were suggested as the most probable ancestors of P.
nigrum. Systematic surveys were conducted in most of the natural habitats of Piper and the regions of cultivation to collect and conserve the existing diversity of black pepper and related species.
Conservation of genetic resources: Conservation of genetic resources is extremely important in context of rapid gene erosion taking place due to a variety of biotic, abiotic, socio political and economic factors. The loss of land races and traditional varieties is rapid in certain crops such as black pepper due to devastating diseases, spread of improved cultivars, deforestation etc. At the Indian Institute of Spices Research (IISR) National repositories have been established for all major spices. A good number of germplasm collections are also being maintained at the All India Co-ordinated Research project on Spices (AICRPS) Centers (Table 1). The National Bureau of Plant Genetic Resources (NBPGR) also maintains germplasm collections of various spices at its regional stations. The germplasm of spices is conserved in clonal field repositories and also in in
vitro gene banks in vegetatively propagated crop species (Nirmal Babu et al. 1999, Ravindran and Babu, 1994, Ravindran et al., 2006).
Table 1. Germplasm collections of spices at major canters in India Crop IISR AICRPS centers Centers of AICRP where these
collections are maintained.
Black pepper 2347 680 Panniyur, Sirsi, Chinthapalli,
Yercaud, Pundibari, Dapoli, NBPGR
Cardamom 436 ≥900 ICRI Myladumpara, Mudigere,
Pampadumpara
Ginger 684 630 NBPGR*, Solan, Pottangi,
Kumarganj, Pundibari, Raigarh, Dholi and NBPGR
Turmeric 1040 1326 Jagtial, Dholi, Pottangi, Raigarh,
Pundibari, NBPGR In-vitro Conservation and Cryo preservation
The germplasm collections conserved in clonal field repositories are under constant threat from various biotic and abiotic stresses. Moreover, conservation of germplasm in seed gene banks is not practical as pepper is heterozygous in nature and commercially grown through vegetative propagation. Hence, in vitro conservation becomes important as a safe alternative. Protocols for slow growth in vitro conservation of pepper and its related species viz. P. barberi, P.
colubrinum, P. betle and P. longum were standardized (Geetha et al., 1995; Nirmal Babu et al., 1996b, 1999). This is achieved by maintaining cultures at reduced temperatures in the presence of osmotic inhibitors at reduced nutrient levels and by minimizing evaporation loss by using closed containers. Cultures of black pepper and related species could be maintained for one year in half strength WPM supplemented with 15 gl-1 each of sucrose and mannitol with 85%
survival.
Long-term conservation by cryopreservation of black pepper seed has also been standerdised as the seeds are recalcitrant and looses viability with the decrease in moisture content. Seeds desiccated to 12 per cent and 6 per cent moisture contents could be stored successfully by cryopreservation in liquid nitrogen (-196°C) with 45% and 10.5% survival, respectively (Chaudhury and Chandel, 1994). Recently technology for cryopreservation of pepper shoots was also developed using encapsulation and dehydration method.
Genetic Resources and Cultivar Diversity
Over 100 named cultivars exist in black pepper. They might have been originated from wild forms during domestication and selection (Ravindran et al., 2000). Considerable variability exists among cultivars for plant, leaf and seed morphological characteristics, yield and quality.
Most of the black pepper varieties are named in vernacular, indicating a specific feature of the vine colour, appearance, leaf shape, spike features or the place from where the vine initially originated or by suffixing “kodi” (means pepper vine) after the name of a place or person.
Cultivar Karimunda is the most popular and it gives consistent yields under varying agro- climatic conditions. Others like Aimpirian, Kottanadan, Neelamundi, Balankotta, Chumala,
Narayakodi, Kalluvally, Kuthiravally, Malligesara and Thommankodi are popular in certain locations. The hybrid Panniyur – 1 is also as popular as Karimunda. Cultivar Kuching is most popular variety in Malaysia. Kottanadan, Kumbhakodi and Aimpirian are cultivars with high oleoresin and essential oil hence gives high quality pepper (Ravindran and Babu, 1994). There is limited variability in pepper germplasm for resistance to biotic and abiotic stresses. The major black pepper cultivars available in India are given in Table 2.
Table 2: Major black pepper cultivars available in India
Cultivar Important Characters
Aimpiryan High yielder, high fruit set, excellent in higher elevations, good in quality
Arakkulammunda Moderate and regular but early bearer, medium in quality.
Balankotta Cultivar with large drooping leaves, moderate but early irregular bearing medium in quality, bold berries.
Bilimallegesara Moderate yielder, good for Karnataka State.
Chengannurkodi Moderate yielder from South Kerala, medium in quality.
Cheppukulamundi Moderate yielder from central Kerala, medium in quality.
Cheriyakaniakadan Popular in north Kerala, moderate and early bearing variety.
Jeerakamundi Cultivar with small leaves, short spikes with high spiking intensity, and small berries; alternate bear.
Kalluvally A promising north Kerala cultivar, good yielder, medium in quality, high dry recovery, drought tolerant.
Karimunda Most popular cultivar suitable for most of the black pepper growing areas, high yielder, regular bearer, medium in quality.
Kottan A cultivar found in north Kerala, moderate in yield, medium in quality.
Kottanadan A high yielding, high quality cultivar from South Kerala, drought tolerant and regular bearer
Kurimalai A cultivar from Karnataka, moderate yielder medium in quality.
Kuthiravally A cultivar with long spikes, high yield and good quality.
Kuttianikodi A moderate yielder from central Kerala with relatively long spikes and good spiking intensity.
Malamundi A moderate yielder, medium in quality.
Malligesara A common cultivar from Karnataka, relatively good in yield.
Manjamundi A moderate yielder from north Kerala, medium in quality.
Narayakodi Popular in south Kerala, moderate yielder, medium in quality.
Neelamundi A good yielder from central Kerala, medium in quality, tolerant to Phytophthora .
Nedumchola A cultivar with small leaves and short spikes, poor yielder.
Neyyattinkaramundi A cultivar from central Kerala, medium in quality and yield.
Perambramunda A cultivar from north Kerala, moderate yielder, medium quality.
Perumkodi A cultivar from central Kerala, moderate in yield and quality.
Poonjaranmunda A cultivar originally from central Kerala, sporadically found in gardens of north Kerala. Moderately good in yield with long spikes and quality.
Thommankodi A cultivar from central Kerala, good yielder and quality.
Thulamundi A central Kerala cultivar, medium in yield and quality.
Uddagara A popular cultivar of Karnataka, good in yield, medium in quality.
Vadakkan A triploid cultivar from north Kerala, medium in quality and yield, very large berries.
Valiyakaniyakadan A cultivar with larger leaves, medium in yield and quality.
Vattamundi A moderate yielder from central Kerala.
Vellanamban Relatively moderate yielder, medium in quality, characterized by the white colour of the young shoot tip.
Source: Botany and Crop improvement of black pepper by Ravindran (2000) Evaluation and Utilization
The shape and size of pepper leaves are highly variable in different cultivars. Still leaf characters play an important role in cultivar identification. The shape and size of leaves are different in the orthotropic and plagiotropic shoots. Kanakamany et al. (1985) used the leaf character - especially the variations in green shades of the abaxial and adaxial surfaces for cultivar classification.
Much of the germplasm was evaluated for biosystematics, genetic variability, cytogenetical indexing, quality parameters and reaction to pest and diseases and catalogued. A detailed descriptor was prepared and published by IBPGR for black pepper characterization and cataloguing. Good variability was observed between and within the cultivars (Like Karimunda and Kottanadan). Ratnambal et al. (1985) reported rich intravarietal variability for morphological and quality characters in cv. Karimunda. Ravindran and Nirmal Babu (1994) reported variability for morphological characters of black pepper cultivars. As flavour is the most important factor contributing to the pepper quality and aroma, more emphasis was given to the improvement in essential oil composition and content. In pepper cultivars the essential oil content reported was 0.4-7 percent and piperine content was from 2-7.4 per cent. Raju et al. (1983) also observed variability in quality characters among cultivars. Gopalam and Ravindran (1987) have carried out quality indexing of all important cultivars and categorized them into three classes viz. high, medium and low. The promising lines selected for various traits are presented in Table 3. The superior cultivars are being incorporated in the breeding programmes.
Genotypic and phenotypic variability, heritability and genetic advance using 28 lines including hybrids and open pollinated progenies were studied by Ibrahim et al. (1985 a, b, c, e 1987a, 1988a) and found that spike yield followed by spike number expressed the highest phenotypic coefficient of variation and the lowest variability by fruit weight. From this study, it is concluded that for yield improvement of black pepper, characters such as spike yield and spike number were more important. Heritability values varied from 28 to 81 per cent with the highest value being for fruit weight followed by spike length. Spike yield and spike number having low heritability indicated that these characters were highly influenced by environmental fluctuations.
The highest genetic advance was observed with spike yield, which indicates the advantageousness of this character for selection. However, lowest value of fruit weight indicates the only marginal improvement on selection for this character.
Table 3: Black pepper germplasm having specific traits
Traits Cultivars/accessions/species 1. Tolerant/Resistant to foot rot
(Phytophthora capsici)
Balankotta, Kalluvally, Narayakkodi, Neelamundi, Uthirancotta, P24, P1534, P339, Coll: 1041, C 1095, C 847, C 1090, HP 780, P. colubrinum
2. Tolerant/Resistant to slow decline ( Meloidogyne incognita)
Pournami (Variety), Acc. No. 4163, 4175, 1090, 334 (Cultivated), Acc. No. 3219, 3286, 3287, 3311 (wild) (Radopholus similes) Acc. No. 820, 3141, 3200, 3283, 3291, 3299 (wild), HP 305
(Hybrid) 3. Tolerant/Resistant to ‘pollu’
(Longitarsus nigripennis) Acc. No. 816, 841, 1084, 1114, 2070 (cultivar); P. barberi, P.
Chaba, P. hymenophyllum, P. longum
4. Adaptable to high elevation HP 34, HP 105, HP 812, HP 728, Coll.1041*; HP 105 & HP 813
5. Tolerant to drought KS 51, KS 69, KS 114; Panniyur-5, Acc. No. 4216, 4226, 1343, 1368, 1226
6. Medicinal value P. longum, P.mullesua, P. betle, P.chaba 7. High quality
Essential oil
Oleoresin
Piperine
Balankotta, Kottanadan, Kumbhakodi, Acc. No. 41, 43, 49, Culture - 5128
Kottanadan, Kumbhakodi, Acc. No. 41, 164
Kottanadan, Kumbhakodi, Acc. No.41, 164
8. Ornamental value P. crocatum, P. magnificum
Mathew et al. (1999) studied the genotypic and phenotypic coefficient of variations, genotypic and phenotypic correlation and heritability in respect of 14 quantitative characters in 50 cultivars of black pepper and suggested little influence of the environment on them. Ravindran et al., (1992) studied the inheritance of shoot tip colour in black pepper and suggested that two pairs of genes having complementary action control the shoot tip colour in black pepper.
Positive and significant relationship between biomass production and economic yield was established for all the cultivars studied (Mathai and Nair, 1990). Higher photosynthates and efficient translocation of synthesized sugars are important for higher yield, which in turn depends on leaf area. The efficient dry matter partitioning capacity of high yielding cultivars was strongly influenced by their total biomass production. To attain high economic yield in black pepper, the laterals should have high biomass production. Panniur-1 having more laterals, spikes and berries, higher mean berry weight, higher rate of photosynthesis and translocation, produced higher yield than the rest of cultivars (Aravindakshan and Krishnamurthy 1969, Mathai, 1986).
Crop improvement
In the effort to raise production and productivity of spices, primary importance was given for evolving high yielding varieties with good quality attributes. Evaluation and selection within the germplasm has led to the isolation of many elite varieties. Most of these varieties were evolved
by clonal selections from germplasm, while a few are from seedling selection and very few are due to recombination breeding (Edison et al., 1991, Ravindran and Johny, 2000).
Pepper is propagated by seeds as well as by cuttings. The asexual method of propagation has great advantage in breeding programmes for developing superior genotype. The important goals of crop improvement are higher yield, improvement in quality, higher levels of essential oil, piperine and oleoresin; resistance to foot rot disease caused by Phytophthora capsici, resistance to nematodes, Radopholus similis and Meloidogyne incognita, resistance to insect pests especially the pollu beetle (Longitarsus nigripennis), resistance to drought, shade tolerance, responsive low inputs, suitable for for high elevations and mixed cropping. (Ravindran et al 2000).
Black pepper has good variability for various agronomic and quality attributes but variability is limited for resistance to biotic and a biotic stresses. Various methods of breeding like clonal selection, hybridization, open pollinated progeny selection, and mutation and polyploidy have been employed in improving black pepper. More emphasis is given to convergent breeding programmes of various spice crops to develop high quality lines and resistant line to biotic and abiotic stresses, in addition to higher yield. A large number of inter cultivar hybrids, open pollinated seedling progenies and accessions in germplasm are being evaluated for this purpose.
Biotechnological approaches are also being used mainly for developing pathogen resistance. So far 12 black pepper varieties were released for cultivation in India. Of these only two are hybrids while others are of clonal selections from germplasm or from open pollinated progenies. PLD 2 is a high quality variety suitable for industrial extraction of oils and oleoresins, while Pournami is tolerant to root knot nematode. Panniyur 1 has bold berries while Panniyur 5 is suitable for mixed cropping. The improved varieties released in black pepper along with its salient features are given in Table 4.
Table 4: Released black pepper varieties and their characteristics
Quality attributes (%)
Variety Av.
Yield- dry
(kg/ha)
Driage
(%) Piperine Oleoresin Essential oil
Remarks
Panniyur 1 (Hybrid between Uthirankotta x Cheriyakaniya kadan)
1242 35.3 5.3 11.8 3.5 Spikes are long with large berries high in oleoresin. Early bearing, performs well under open situations. Suitable to all pepper growing regions. Not suited to heavily shaded areas.
Panniyur 2 (Open pollinated progeny of Balankotta )
2570 35.7 6.6 10.9 3.4 Shade tolerant, rich in oleoresin and piperine. Suited to all pepper growing tracts of Kerala.
Panniyur 3 (Hybrid between Uthirankotta x Cheriyakaniya kadan)
1953 27.8 5.2 12.7 3.1 Vigorous and late maturing, suitable for all pepper growing region, performs well under open situation. Long spikes &
bold berries.
Panniyur 4 (Clonal selection from Kuthiravally)
1277 34.7 4.4 9.2 2.1 Stable yielder, performs well under adverse condition including partial shade.
Panniyur 5 (Open pollinated progeny of Perumkodi )
1098 35.7 5.3 12.3 3.8 This is a shade tolerant long spiked variety better suited for mixed cropping in coconut/
arecanut gardens. Tolerant to nursery diseases.
PLD –2 (Selection from Kottanadan)
2475 - 3.3 15.5 3.5 High oleoresin line
recommended for Trivandrum and Quilon districts of Kerala.
Subhakara (Selection from Karimunda)
2352 35.5 3.4 12.4 6.0 Adaptable to all pepper growing tracts. High quality line with high oleoresin and essential oil.
Sreekara (Selection from
Karimunda)
2677 35.0 5.1 13.0 7.0 Adaptable to all pepper growing tracts. High quality line with high oleoresin and essential oil.
Panchami (Selection from Aimpiriyan)
2828 34.0 4.7 12.5 3.4 Late maturing variety with excellent fruit set.
Pournami (Selection from
Germplasm)
2333 31.0 4.1 13.8 3.4 High yielding variety, tolerant to root knot nematode. Suited to all pepper growing regions of Kerala.
Panniyur 6 (Clonal selection from Karimunda)
2127 33.0 4.9 8.3 1.3 Steady and stable yielder
tolerant to drought and adverse climatic conditions. Suitable for open condition as well as partial shade
Panniyur 7 (Open pollinated progeny of Kalluvally)
1410 33.6 5.6 10.6 1.5 Vigorous, hardy and a regular bearer, long spike, high piperine tolerates adverse climatic condition suitable open and shaded conditions.
Malaysia and Indonesia have research programmes on black pepper. Malaysia has developed two important varieties. The variety Semongok Perak was developed by clonal selection and Semongok Emas by hybridization followed by back crossing. The latter is tolerant to Phytophthora foot rot disease. In Indonesia two selections – Natar 1 and Natar 2 have been evolved. In Madagascar selections Sel IV.1 and Sel IV.2 have been developed from cultivars introduced from Indonesia (Ravindran et al., 2006).
Selection
The selection programmes attempted in black pepper are selection from within germplasm (inter- cultivar selection), within a cultivar (intra cultivar selection ), and selection in segregating open
pollinated or selfed progenies. An elite plant once identified by any of these methods can form the basis of a new variety, which can be multiplied vegetatively and subsequently released after evaluation for yield and quality traits.
Selection was carried out in the most popular cultivar of Kerala- Karimunda. Out of 216 elite plants evaluated for yield and quality and two lines under the name Sreekara and Subhakara were identified and released for cultivation (Ratnambal et al, 1990). They have high yield potential of 12,000 kg/ha and 12, 640 kg/ha, respectively and are rich in essential oil (Fig 2 ).
Panniyur-4, a clonal selection from cv. Kuthiravally and Panniyur-6, a clonal selection from local cv. Karimunda were released from Pepper Research Station, Panniyur (KAU) under AICRP on Spices, while PLD-2 is a selection from cv. Kottanadan by the Central Plantation Crops Research Institute, Research Centre, Palode.
Selection from Germplasm: Panchami and Pournami are the improved varieties developed through selection from germplasm. Panchami is a selection of Aimpiriyan with high yield and good quality and high fruit set, while Pournami was tolerant to root knot nematode – Meloidogyne incognita. These two cultivars have good yield attributing characters. Panchami has medium long spikes (11.2-cm mean), high spiking intensity (77 spikes/100 nodes), high percentage of hermaphrodite flowers (91.5%) and high fruit set (82%). The spikes have the typical 5-rowed arrangement of fruits and the twisted nature of the spike. It is a late maturing type, fruits mature for harvesting in about 8-9 months after flowering (Ravindran et al., 1992 b,c ). Pournami was selected based on its good yield potential and tolerance to root knot nematodes.
Coll. 1041, a germplasm accession is found very promising in the experimental trials conducted at Valparai, at high elevation and this is also field tolerant to foot rot disease. This line was recommended for release recently for cultivation under the name “IISR Thevam”. It is suitable for high altitude areas of South India (upto 3000 ft. MSL).
Fig. 2: Subhakara a high yielding high quality selection from cv. Karimunda
Selection from Open Pollinated Progenies: Pepper, being heterozygous segregation is always expected in the open pollinated (OP) and selfed progenies. Because of the geitonogamous mode of pollination, the open pollinated progenies are comparable to selfed offsprings. Thus, there is a fair chance to locate useful genotypes in open pollinated progenies. Ibrahim et al. (1986) reported comparative genetic variability within the open pollinated progenies of a few varieties of black pepper.
At the Pepper research Station, Panniyur, three varieties namely Panniyur-2, 5 and 7 were developed through selection from OP progenies of cvs. Balankotta, Perumkodi and Kalluvally, respectively. Panniyur 2 with a yield potential of 2570 kg dry pepper / ha and Panniyur-5, 1098 kg dry pepper / ha have high (35.7%) dry recovery. Panniyur-2 gives pepper of high quality with 6.6 % piperine and 10.9 % oleoresin and 3.4%oil. Panniyur-2 and 5 have good yield, medium long spike (12.3 and 13.1 cm), high bisexual flowers (97 and 96%), fruit set (74 and 87%), number of fruits/spike (74 and 103), fruit volume (120 and 104 cc/1000 fruits) and higher fruit weight (127 and 110g/1000 fruits). Panniyur-7 is characterized by long spikes and high piperine content.IISR- Shakti, a high yielding variety tolerant to Phytophthora was selected (P24) from open pollinated progeny of Perambramundi.
Hybridization
Wide variability exists among the cultivars of black pepper for yield and quality attributes.
Hybridization in pepper mainly exploit the inter cultivar variability. For hybridization, cultivars are taken as parental units and crossings are done among them. Genetic improvement through hybridization generally involves selection of parents, hybridization and selection of superior genotypes.
Inter-cultivar Hybridization: Information on the breeding value, general or specific combining ability of pepper cultivars is not available for selection of parental combinations. In the absence of such information the available gene pool is used at random for inter-cultivar hybridization with parents selected based on ossessing one or few good characters.
Fig. 3: Panniyur 1 the most popular black pepper hybrid
Evaluation of progenies of many crosses at the Pepper Research Station, Panniyur led to the development of Panniyur-1 (Fig 3) which is a selection of a cross between cv. Uthirancotta and Cheriyakanikkadan. A second variety, Panniyur-3, was also developed from the cross involving the same parents.
At IISR, a large number of crosses involving many cultivars were made and the progenies tested for yield in preliminary trials. The promising F1 plants were multiplied and planted for comparative yield evaluation. Among them three lines (HP-34, HP-105, HP-813) having good
yield and adaptability for higher elevation have been identified and are in advanced stages of evaluation. HP 813 (Cholamundi X Panniyur-1) and HP 105 (Narayakodi X Neelamundi) were released under the names “IISR Malabar Excel” and “IISR Girimunda”, respectively.
Apart from these, a large number of inter-cultivar hybrids are under different stages of testing for yield and resistance to Phytophthora. Of the hybrids a few have shown high yield as well as tolerance to Phytophthora.
Inter-specific Hybridization: In an attempt to bring resistance genes from wild relatives to cultivated types interspecific hybrids between P. nigrum x P. attenuatum and P. nigrum x P.
barberi was successfully developed (Sasikumar et al. 1999). The hybrids exhibited distinct morphological and anatomical features but are not useful.
Polyploidy breeding
A natural triploid (2n (3x) =78), Vadakkan bearing large leaves; very bold fruits with low fruit set was identified by IISR from the germplasm. The progenies of this cultivar exhibited wide morphological variations and varying chromosome numbers (cytotypes) (2n=52-104), however, none of these chromosomal variants have any horticulturally useful traits (Nair et al., 1993). An induced tetraploid (2n=104) was developed by treating the seeds of Panniyur-1 with 0.05%
colchicine (Nair and Ravindran, 1992). This tetraploid has larger and thicker leaves but the growth was slower than the diploid parents, and is difficult to establish in the field. A tetraploid variant having an extra bold fruits from Panniyur 1, was also reported by Ibrahim et al. (1987).
Mutation breeding
Attempts were made using gamma rays as source of irradiation. Apart from seeds, rooted cuttings were also irradiated and raised. Irulappan et al. (1982) and Ravindran et al. (1986) used 1-4 kr gamma rays for inducing variability in Karimunda, Panniyur 1, Kuthiravally, Kalluvally (Pulpally), Kalluvally (Malabar), Thommankodi and Aimpiriyan. Irradiation adversely affected the germination of seeds. As the dose increased, germination was delayed. The M1 population expressed morphological abnormalities such as chlorophyll changes, twinning of seedlings and rosette leaves. Chandy et al. (1980) did not observe any mutants in the M1 by treating vegetative buds with EMS and further generations were not studied. Programmes using ionizing radiations for generation of variability for selection of improved genotypes are in progress in Sri Lanka and Malaysia with some encouraging results.
Biotechnological Approaches
Micropropagation: Micropropagation has superiority over conventional method of propagation.
It has high rate of multiplication and provide disease free plants. Methods for micropropagation of black pepper were reported using various explants from both mature and juvenile tissues (Broome and Zimmerman 1978, Mathew and Rao 1984, Philip et al. 1992, Nazeem et al. 1993, 2004, Nirmal Babu et al. 2007). Multiple shoots can be induced using BA (N6- benzyl adenine) in the culture medium either alone or in combination with auxins (Fig 4). These shoots could be easily rooted using growth regulator free basal medium and hardened by transferring into polybags/ cups containing garden soil, perlite/ retted coir pith and sand in equal proportions and kept in humid chamber for 20-30 days. Phenolics and endogenous bacterial contamination
severely hamper establishment of black pepper cultures (Chua 1981, Raj Mohan 1985, Fitchet 1988). Treating the explants with fungicides prior to routine sterilisation followed by frequent transfer to fresh medium, use of activated charcoal and antibiotics in the culture media was suggested in reducing phenolic interference and systematic contamination . A commercially viable protocol for large scale in vitro multiplication of black pepper was reported by Nazeem et al (2004).
Fig 4 Micropropagation of black pepper and flowering of TC plants in field
Protocols were standardized for micropropagation of other economically and medicinally important species of Piper viz. Piper longum and P.chaba, P. betle, endangered P. barberi and P. colubrinum (Nirmal Babu et al, 2005). Preliminary field performance of micropropagated plantlets of piper species indicated that they are at par with clonally propagated plants (Nirmal Babu et al 2003).
Field evaluation of Tissue culture propagated pepper: Large scale field evaluation of tissue culture (TC) plants of Black pepper in about 100 ha in all Pepper growing states of India involving Department of Biotechnology, Spices Board, Kerala Agricultural University and Indian Institute of Spices Research (in case of black pepper and cardamom) indicated that the tissue cultured plants are superior to conventional propagules in field performance. In addition they also have better field establishment and early flowering (Fig 4) in the case of black pepper.
(Nazeem et al, 2004, Nirmal Babu et al. 2007). The tissue cultured plants are superior to conventional propagules in field establishment, plant height, internodal length, number of laterals per unit area, number of spikes for unit area, fruit set, mean yield, dry weight, oil content, oleoresin contents etc (Nazeem et al ,2004). Morphological characters coupled with RAPD and ISSR profiling has indicated genetic fidelity among micropropagated plants of Black pepper.
Plant regeneration from callus cultures: Efficient plant regeneration protocol is essential for genetic manipulation of any crop species. Plant regeneration was reported in black pepper from shoot tip and leaf with or without intervening callus phase (Nirmal Babu et al 1997; Nazeem et al 1993, Bhat et al, 1995). Shaji et al (1997) reported variability among genotypes for callus induction and plant regeneration in Black pepper (Fig 5 A, B). Joseph et al (1997) reported cyclic somatic embryogenesis from zygotic embryos, while Nair (2001) and Nair and Gupta (2003, 2005) reported similar results from the integument tissues. This cyclic somatic embryogenesis from maternal tissues like integuments has tremendous potential for automated
micropropagation. These systems are useful for transgenic experiments for transfer of Phytophthora resistance.
Plants were regenerated from leaf and stem explants of other related species of black pepper like Piper longum, P. betle, P. chaba, P. attenuatum and P. colubrinum through both direct and indirect organogenesis (Bhat et al. 1992, 1995, Nirmal Babu et al. 1997, Sarasan et al. 1993, Rema et al. 1995, Madhusudhanan and Rahiman, 1997). Johri et al. (1996) reported regeneration of betel vine through somatic embryogenesis.
Somaclonal variation and in vitro selection for Phytophthora foot rot tolerance: Attempts on induction of variability on somaclones for tolerance to Phytophthora foot rot resistance by Shylaja et al.(1994) and Nazeem et al. (1996) resulted in identification of tolerant somaclones through in vitro selection of calli as well as somaclones using crude culture filtrate and toxic metabolite isolated from Phytophthora capsici.
Synthetic seeds: Artificial or ‘synthetic seeds’ is ideal for low cost plant movement, propagation, conservation and exchange of germplasm. Synthetic seeds are developed by encapsulating in vitro developed small shoot buds in 3% calcium alginate in black pepper. These Synthetic seeds could be stored up to 9 months in sterile water with over 80 % viability (Sajina et al. 1997).
Protoplast culture and development of protoclones: The ‘protoplast’ is a naked cell which is suitable for a variety of manipulations that are not normally possible with intact cells and hence protoplast is an important tool for parasexual modification of genetic content of cells (Vasil and Vasil 1980). Successful isolation and culture of protoplasts were reported in P.nigrum (Sim et al.
1995). Shaji et al. (1998) reported high frequency isolation of viable protoplasts from in vitro
C B
A
Fig 5 Development of transgenics in Black pepper A. Plant regeneration from leaf tissues, B. regeneration of somatic embryos from leaf tissues and C. regeneration transgenics from Agrobacterium treated cultures containing stress resistance gene Osmotin.
derived leaves of both P.nigrum and P.colubrinum. Microcallus formation was observed after 2 months in P.nigrum and 1 month in P.colubrinum. Plant regeneration was observed only in P.colubrinum.
Genetic transformation: Preliminary reports are available on Agrobacterium mediated gene transfer in P. nigrum (Sasikumar and Veluthambi 1994, 1996 a, b). They obtained primary transformants for kanamycin resistance in the cotyledons using Agrobacterium tumefaciens binary vector strains LBA 4404 and EHA 105. Sim et al. (1995) reports Agrobacterium mediated transfer of GUS to black pepper. Trials are in progress at IISR to transform black pepper leaf tissues using Agrobacterium tumefaciens strain EHA containing gene for osmotin, a PR protein known to induce Phytophthora resistance (Fig 5 C).
About 100 putative transgenics were regenerated from the selection medium. PCR testing indicted the presence of osmotin gene in five of them (Nirmal Babu et al 2005).
Molecular characterization and development of mapping population: In recent times there is increased emphasis in molecular markers for characterization of the genotypes, genetic fingerprinting, in identification and cloning of important genes, marker assisted selection and in understanding of inter relationships at molecular level.
Molecular markers like RAPD, AFLP and ISSR polymorphism was used for assessment of genetic variability in black pepper and characterize important cultivars, varieties and related species of black pepper to develop finger prints and to study the inter relationships (Pradeep Kumar et al., 2001, 2003, Babu et al 2003, Ganga et al 2004, Nazeem et al 2005, Keshavachandran et al, 2005, Sreedevi et al (2005)). The study indicated that the intra species divergence in certain species is some times more than that of inter species divergence. This may be due to fact both vegetative as well as sexual reproduction is in operation in most of piper with one of them being dominant and the higher divergence is reflective of sexual reproduction being dominant factor in population build up. Piper nigrum in the wild is cross pollinated and hence, the progenies are expected to carry high levels of heterozygosity (Pradeepkumar et al 2003).
Selection for high yield from heterogeneous seed derived populations led to selection of forms much different from the parents.
A mapping population was developed for preparation of genetic map of black pepper (Nirmal Babu et al., 2003). Johnson et al (2005) used male parent-specific RAPD markers for identification of hybrids in black pepper (Piper nigrum L.). Johnson et al (2003) reported ISSR- PCR is a valuable tool for genetic diversity analysis in spices. Ajith (1997) Ajith et al (1997) used RAPD markers to estimate genetic fidelity of micropropagated Piper longum. Banerjee et al. (1999) reported male sex associated RAPD markers in Piper longum. Anjali et al (2004) studied genetic diversity amongst landraces of a dioecious and vegetatively propagated Piper betle - betelvine using molecular markers. One putative RAPD marker was found to be associated with Phytophthora resistance in black pepper and the marker was converted in to SCAR.
Isolation of R gene candidates: Preliminary work on isolation of genes responsible for agronomically important characters, especially for biotic and a biotic stresses was done. A few
putative genomic and cDNA fragments associated with resistance related genes are isolated.
Research work on isolation, cloning and validation of full length genes is in progress (IISR 2005). Johnson et al (2005) reported a method for isolation and reverse transcription of high quality RNA from Piper species. In an attempt to isolate resistance genes in black pepper, molecular cloning of a cDNA fragment encoding the defense related protein β-1,3-glucanase in black pepper (P. nigrum L.) and methyl glutaryl CoA reductase in Piper colubrinum was reported (Girija et al 2005a , b). Bhat et al (2005) reported isolation and sequencing of CMV coat protein gene infecting black pepper. Bioprospecting of novel genes from spices is attempted and the presence of pea lectin genes and tomato protease inhibitor genes was identified using heterologus probes in black pepper.
Future
With the knowledge gained so far the future breeding strategies in black pepper must focus on convergent breeding to bring together the various yield and quality attributes distributed in different cultivars through well planned crossing programme. This can be supplemented by marker based selection to reduce breeding time. With respect to disease and pest resistance mobilization of genes from related taxa and species is a good option involving identification, isolation and genetic transformation if necessary. Spices being what they are form a gold mine for mining of important genes responsible for various industrial, pharmaceutical and medical processes. Industrial production of useful secondary metabolites, flavour and colouring compounds is another area of interest where the compounds are high value in nature.
Cardamom
Cardamom (Elettaria cardamomum Maton) acclaimed as the 'Queen of Spices' is the true cardamom (Fig 6) belonging to the family Zingiberaceae under the natural order Scitaminae. It is one of the most important and highly priced spices. Cardamom is commonly cultivated beneath evergreen forest trees of Western Ghats of South India mainly in Kerala, Karnataka and Tamil Nadu. It is a shade loving plant thriving well in elevations up to 600-1200m above MSL under an average annual rainfall of 1500-4000mm and temperature range of 10-350C. Humid tropical climate and soil rich in organic matter is ideal for cardamom cultivation.
Fig 6. A cardamom clump in bloom and fruit set
Area, Production and Trade
India has been the world's largest producer of cardamom until 1979-80. Now Guatemala emerged as world's premier producer and exporter of cardamom accounting for about 90 per cent of the global trade. Unlike in India, where cardamom is grown largely as a small holder crop it is grown on plantation scale in Guatemala. No realistic estimates are available for total area and production of cardamom in the world. In 2004- 2005 cardamom was grown in 655780 ha in India and production was 10190 tonnes of which 650 tonnes was exported.
The major consumers of cardamom are India, Saudi Arabia, other Arab countries, Europe and Japan. At present, India is the second largest consumer of cardamom in the world after Saudi Arabia. According to Spices Board, the domestic consumption of cardamom in India was 9,500 tonnes in 2000 and 12,500 in 2005.
Origin and distribution
India is considered the native home of Elettaria cardamomum though the major centre of diversity for the genus is the Sarawak (Malaysia) and Borneo region, from where eight species have been listed (Sakai and Nagamasi, 2001). Natural population’s cardamom now exists only in the evergreen forests of Western Ghats. In India, genus Elettaria is represented only by one species (E. cardamomum).
Botany and Systematics
Cardamom (Elettaria cardamomum Maton) belongs to the order Scitaminae under the family zingiberaceae. The genus Elettaria consists of seven species distributed in India, Sri Lanka, Malaysia and Indonesia of these only E. cardamomum is with economic importance (Holttum 1950, Willis 1967).
Cardamom is a herbaceous perennial (2-5 m in height) with underground (subterranean) rhizomes and aerial leafy stems (tillers) made of leaf sheaths (Fig 7). Studies on vegetative growth indicated that suckers continue their growth for a period of about 18 months from the time of emergence (Madhusoodanan et al. 2002). The development of reproductive buds (panicles) takes place in about 10 to 12 months (Krishnamurthy et. al., 1989). Inflorescence is a long panicle arising from the underground stem, but comes up above the soil. The linear growth of panicles extends over a period of about seven months. The growth habit of the panicles and the shape as well as the size of the capsules varies in different cultivated varieties/types of cardamom. Flowers are arranged in clusters (known as cincinni) subtended by scale leaves.
Flowers are bisexual, bracts linear, oblong and persistent, sepals 3, petals 3, unequal, lip longer with violet tinge carpels 3, style 1, ovary - trilocular, axile placentation, ovules-numerous in each carpel. Normally flowering in cardamom could be seen throughout the year on panicles produced during the current as well as in previous year (Fig 7). The peak flowering is spread over a period of six months from May to October. The time required to reach full bloom stage from flower/bud initiation ranges from 26 to 34 days and capsule development takes about 110 to 120 days from the full bloom stage (Parameswar and Venugopal, 1974).
In general maximum number of flowers open during early hours of the day 3.30 – 8.00 AM immediately followed by the anthesis. The dehiscence of anthers took place immediately followed by anthesis with maximum pollen bursting between 5.30 - 6.30 AM (Pattanshetti and
Prasad, 1972, KAU, 2001). The pollen grains were round and mostly found in single, measured on an average 87.6 µ in diameter. Though apparently 85.2 % of the pollen grains appeared fertile, germination tests showed that the maximum of 70.1% germination in artificial media containing 20 per cent sucrose and 1 per cent agar solution. Studies on the viability of the pollen grains indicated only 6.5% viability after 2 hours of storage and 0 % after 6-8 hours of storage (Pattanshetti and Prasad, 1972). However cardamom pollen can be stored successfully in liquid nitrogen (Geetha 2002).
Fig 7: A field view of cardamom plantation
The most significant component of cardamom, as spice, is the volatile oil with its characteristic aroma, described generally as camphory, sweet, and aromatic spicy. This is due the presence of 1, 8 cineole, d- -terphenol, terpinyl acetate, limonene, sabinene and borneol (Guenther 1950).
The dominance of 1, 8- cineole and -terpinyl and linalyl acetates, in the composition, make the cardamom oil unique (Lewis et al 1966; Salzer 1975; Wijeskera and Jayawardena, 1978).
Pollination
Cardamom has bisexual flowers, self compatible but cross-pollination is moe common. Apis cerana and Apis dorsata are the predominant pollinators (Fig 8). Cardamom flowers remain in bloom for 15-18 hours and stigma receptivity and pollen viability were reported to be maximum during morning hours between 8 AM and 10 AM. Pollination during this time gives about 72%
fruit set. Thereafter, the stigma receptivity decreased gradually resulting in the minimum fruit set of 24%. The active foraging of bees is seen in the morning hours of the day resulting higher fruit set in cardamom.
Fig 8: Bee pollination in Cardamom
The extent of fruit set recorded in different months indicated that there was high percentage of fruit set (50 to 59 per cent) during June, July, August and September because of humid atmosphere that prevailed during this period. However, during the dry season from December to March, there was practically very little fruit set (Parameswar, 1973, Parvathi et al., 1993, Belavadi et al. 1997, 1998, 2000).
Cytology
The somatic chromosome number of cardamom is reported to be 2n = 48 (Gregory, 1936;
Sharma and Bhattacharya, 1959). Chakravarti (1948) reported 2n = 52. Variations in chromosome numbers were observed in Mysore and Malabar varieties of cardamom indicted that aneuploidy as well as structural alterations in the chromosome have contributed to the varietal differentiation (Chandrasekar and Sampath Kumar, 1986). Earlier workers have reported that cardamom is of amphidiploid origin from wild species, which are probably extinct. Allied genera such as Globa, Balbifera, Phoemaria, Amomum sp. and Alpinia spp also possess 2n=48 and are considered to be evolved from a common basic number, X=12.
Collection and Conservation
The genetic resource of cardamom is being eroded rapidly with the changes in habitat of the Western Ghats and needs systematic exploration and collection of germplasm. A good collection of cardamom is maintained at IISR, Indian cardamom Research Institute, Myladumpara and various centres of All India Co ordinated Research Project on Spices (Table 1). Cardamom being a vegetatively propagated crop, germplasm is presently maintained in clonal repositories in the field which is labour intensive and exposed to hazards such as outbreak of pests, diseases and drought. Field repositories of cardamom are also vulnerable to diseases such as ‘katte’ and rhizome rot resulting in considerable loss. Therefore, in vitro conservation of germplasm, in addition to field gene banks, would provide safety of germplasm collections.
Nirmal Babu et. al., (1999) and Geetha (2002) reported a method of inducing slow growth on half-strength Ms medium without growth regulators, supplemented with 15 g/L each of sucrose and mannitol in screw-capped culture tubes and incubation at 22±2oC with photoperiod of 12 h light/12 h dark and a light intensity of 2500 lux. Cultures maintained under these conditions can be conserved for one year without subculture. Conserved plantlets multiplied normally and were planted with high percentage of establishment and normal growth.
Long term storage by means of cryopreservation using liquid nitrogen at - 196oC:
Cryopreservation of cardamom seeds and encapsulated, vitrified shoot tips in liquid nitrogen has been reported by Chaudhary and Chandel (1995, Ravindran et al 2004).
Genetic Resources and Cultivar Diversity
Based on the adaptability, nature of the panicle, shape and size of fruits, the cultivated cardamom is grouped into three botanical varieties viz. Malabar, Mysore and Vazhukka (Sastri, 1952). The characteristic features of these varieties are given in Table 5.
Table 5 Characteristic features of the three varieties of cardamom
Characters var. Malabar var. Mysore var.Vazhukka
Adaptability Lower altitudes 600-900 m MSL
Higher altitudes 900- 1200 m MSL
Wide range Areas of cultivation Karnataka Kerala and parts of
Tamil Nadu
Kerala
Plant growth Medium Robust Robust
Panicles Prostrate Erect Semi erect
Capsules Round or oblong Bold,elongated Round to oblong
Leaf petiole Short Long Long
Capsule colour at maturity
Pale/golden/yellow Green Green
Characterization and evaluation
Cardamom germplasm exhibits rich genetic diversity for various agronomic, yield and quality attributing characters. A detailed descriptor was published by IPGRI for characterization and documentation of cardamom germplasm (IPGRI, 1994). Prasath et al (2001) reported high variability for panicle length and yield per plant. Variations have also been reported in important characters like, branching of inflorescence, fruit (capsule) size, shape, leaf and plant pubescence, retention of green colour etc. (Madhusoodanan et al., 1994).
Cardamom is valued for its volatile oil which varies from 6.5 to 10.5 per cent. The major chemical constituents which impart sweet flavour to the oil are terpinyl acetate, linalyl acetate, linalool etc. ‘Mysore’ type possesses more terpinyl acetate compared to ‘malabar’ while the later possesses more 1, 8-cineole which impart harsh camphory note to the oil (Sarathkumara et al., 1985). Rich variability exists in cardamom with regard to essential oil content and the quantity of 1,8-cineole and alpha-terperyl acetate. Evaluation of germplasm has also led to the identification of two accessions (Acc.221 and Acc.218), which contain 7.8 % essential oil. Its oil has high concentration of aroma bearing constituents such as alpha terpinyl and linalyl acetates and low concentration of 1, 8-cineole (Zachariah et al, 1998). The Mysore genotype, PR-107 was found superior in quality because of high content of esters, such as alpha terpinyl acetate, geranyl acetate and linalyl acetate (Raj et. al. 2000). Seventeen accessions resistant to mosaic (katte virus) disease were identified among 134 disease escapes collected from hot spots (Venugopal, 1999).
Crop Improvement
The main focus of Cardamom breeding in addition to high yield are resistance to biotic stress viz., viral diseases such as ‘katte’ and ‘kokke kandu’ and fungal diseases such as rhizome rot, clump rot and capsule rot; drought tolerance; plants with bold capsules with more number of seeds/fruit; Higher percentage of capsule dry recovery (>22%), higher percentage of essential oils, α -terpenyl acetate which is responsible for the aroma and flavour and varieties with wide adaptability.
Cardamom breeding depends on selections from germplasm and from open pollinated progenies of popular cultivars. Twelve high yielding varieties of cardamom were released for cultivation (Table 6). IISR Vijetha is katte virus tolerant line while IISR Avinash and ICRI 4 are relatively
tolerant to rhizome rot. PV 1 has long and bold capsules. The variety CCS 1 has compact growth habit and is suitable for high density planting. (Fig.9). Hybridization between NKE, RR, extra bold and Multibranch types are in progress with an aim to evolve desirable types.
B A
C D
Fig 9 Important released varieties of Cardamom, A. CCS I a high yielding short plant type, B. Green Gold the most sought after farmer’s selection of cardamom, C. IISR Avinash a rhizome rot resistant variety, D. IISR Vijetha a katte resistant variety
Clonal selection
All the existing improved varieties have been evolved by selection for desirable characters such as higher yield and superior capsule characters. Selection in cardamom is based on both qualitative and quantitative characters from preliminary, comparative yield trial and multilocation trials to confirm the superiority of the selected clone.
Hybridization
Intervarietal hybridization was made between identified superior cultivars for deriving lines with high yield, ‘katte’ resistance and drought tolerance. On farm trials of these varieties are in progress (Madhusoodanan et al.,1999).The promising lines from these trials are given in Table 7.
Table 6: Released varieties of cardamom with yield and quality characteristics
Sl.
No.
Variety Source Yield
(kg/ha)
Essentia l oil %
1,8 cineole
%
α - Terpeny l acetate
%
Capsule shape
Areas recommended for cultivation 1. IISR
Coorg Suvasini
IISR, CRC
Appangala 409 8.7 42 37 Oblong Kodagu&Hass
an districts of Karnataka
2. PV-1 KAU,
Pampadump ara
260 6.8 33 46 Long All cardamom
tracts of Kerala &
Karnataka 3. Mudigere
1 UAS,
Bangalore 275 8.0 36 42 Oval Malnad region
of Karnataka 4. Mudigere
2 UAS,
Bangalore 476 8.0 45 38 Round Traditional
cardamom growing Tracts of hill zones of Karnataka 5. ICRI-1 ICRI,
Myladumpar a
325 8.3 29 38 Round South Idukki
zone of Kerala 6. ICRI-2 ICRI,
Myladumpar a
375 9.0 29 36 Oblong Vandanmettu
&
Nelliampathi zones of Kerela 7. ICRI-3 ICRI,
Myladumpar a
439 6.6 54 24 Oblong Hill zones of
Karnataka 8. ICRI-4 ICRI,
Thadiyanku disai
455 6.4 -- -- Globose Lower Pulneys
in Tamil Nadu 9. IISR
Avinash
IISR, CRC, Appangala
847 6.7 30.4 34.6 Oblong Rhizome rot
infested areas 10. IISR
Vijetha 1 IISR, CRC,
Appangala 643 7.9 44.9 23.4 Oblong Moderate to
high shaded mosaic infested areas
11. PV-2 KAU,
Pampadump ara
982 10.45 -- -- Long Cardamom hill
reserves of Kerala 12 Njallani
Green Gold
Farmers
Selection 1600 -- -- -- bold All cardamom
growing regions Source: Advances in Spices Research, Agrobios, Jodhpur.
Table 7: Promising cardamom hybridization derived lines evolved at ICRI, Myladumpara Hybrid combinations Projected yield (kg/ha)
MCC 16 x MCC 40 610 MCC 61 x MCC 40 675 MCC 21 x MCC 16 650 MCC 21 x MCC 40 870 MCC 16 x MCC 61 800
