2. HORTICULTURAL SCIENCES
2.2 FRUIT CROPS .1 Mango
2.2.6 Production Technologies of Fruit Crops .1 Mango
Rootstock research and canopy management: Three semi-vigorous mango varieties (Pusa Arunima, Pusa Surya and Amrapali) were evaluated on five polyemebryonic rootstocks (K-2, K-3, K-5, Kurakkan and Olour) for various horticultural traits. Extremely dwarf trees of Pusa Arunima (41.05 and 43.34%) lower than Olour and K-3) were found on K-2 rootstock. Both
Semi-quantitative PCR of C-repeat binding factors (CBF1 and CBF2) under cold stress in papaya genotypes
K-2 and K-3 reduced the plant height in Pusa Surya by 37.19 and 18.60%, respectively than Olour. Significantly lower tree volume of Pusa Surya was found on K-2 and K-5 rootstock. Olour, K-2 and K-5 reduced tree volume in Amrapali. In Pusa Arunima, higher fruiting density (8.59 fruits /m3 canopy volume) was found on K-2 rootstocks followed by K-5. In Amrapali, trees on K-2 and had the higher fruiting density (6.28 and 7.11 fruits /m3canopy volume), respectively. In Pusa Arunima, the heaviest fruit (192.05 g) was found on K-3 rootstock.
Rootstock did not affect fruit quality. Significantly highest fruit weight in Pusa Surya was recorded on K-2 rootstock (269.73 g) followed by Kurakkan (245.66 g). It had higher pulp and stone ratio (5.85:1) on K-2 rootstock, while Pusa Surya on Kurakkan had the highest acidity (0.49%). In Amrapali, heaviest fruits were produced on K-3 rootstock followed by Kurakkan rootstock.
However, significantly higher pulp acidity (0.25%) and ascorbic acid content (28.07%) in Amrapali were recorded on Olour and K-5 rootstocks, respectively.
Similarly, growth, yield and fruit quality parameters of two commercial vigorous mango cultivars (Mallika and Dushehari) were assessed on three polyembryonic rootstocks, i.e. K-5, Kurakkan and Olour. Mallika was found taller on K-5 and Olour rootstocks. Dushehari on Olour was found vigorous followed by Kurakkan.
Olour and Kurakkan rootstocks exhibited highest yield efficiency on Olour, along with heaviest fruits but there was not much influence on pulp content, pulp and stone ratio, TSS and titratatble acid content. Higher pulp and stone ratio and pulp acidity in Dushehari was noticed on Kurakkan rootstock.
2.2.6.2 Citrus
Effect of different rootstocks on growth and quality parameters Kinnow mandarin: Eight-year-old Kinnow mandarin raised on different rootstocks was evaluated with respect to their growth, fruit yield and quality.
Rootstock imparted significant influence on plant height and canopy volume and it was recorded maximum on Jatti khatti rootstock (4.12 m; 25.52 m3) followed by rough lemon (3.55 m; 20.31 m3) and Karna khatta (3.00 m; 18.78 m3). Fruiting density and yield efficiency was recorded high on Jatti khatti rootstock
(28.04 m3; 6.91) followed by sour orange (16.29 m3; 3.86). Fruit weight (250.66 g) was recorded maximum on Jatti khatti rootstock followed by rough lemon (238.32 g) and Karna khatta (225.00 g). The juice recovery percentage was however, recorded maximum (56.00, 50.00, and 47.31%) on sour orange, Rangpur lime and Jatti khatti rootstocks, while minimum (32.38%) was recorded Carrizo citrange rootstock. Similarly, TSS was recorded maximum in Kinnow budded on Rangpur lime and Jatti khatti rootstocks (13.22°Brix). The average number of fruits/plant was recorded maximum on Jatti khatti (290) followed by rough lemon (257) and Troyer citrange (235), while it was minimum on Carrizo citrange rootstock (120).
2.2.6.3 Grapefruit
The tree growth of grapefruit cvs Marsh Seedless and Redblush was significantly influenced when budded on eight rootstocks. The trees of Marsh Seedless were more vigorous (220.32m3) on sour orange rootstock. In Redblush, highest canopy volume (175.65 m3) was recorded on RLC-4 rootstock. The highest fruit yield in Marsh Seedless (23.13 kg/tree) and Redblush (42.13 kg /tree) was contributed by Billikichli and RLC- 4 rootstocks, respectively. The fruits of Marsh Seedless had the lowest peel thickness (3.81 mm) on Jatti khatti and sour orange rootstocks. The highest juice content (50.20%) was on RLC-4 rootstock followed by sour orange and rough lemon, while in Redblush had the highest juice content (50.40%) on Billikichli rootstock.
Juice TSS was higher in Redblush followed by Marsh Seedless.
2.2.6.4 Sweet orange
The tree vigour of two newly released sweet orange cultivars, namely, Pusa Sharad and Pusa Round were significantly influenced due to different rootstocks. Rootstock RLC-7 was most vigorous rootstock, having canopy volume of 50.03 and 44.89 m3, respectively, while it was lowest in Pusa Sharad on Yama Mikan and Pusa Round on C-35 rootstocks. The highest number of fruits per tree basis in Pusa Sharad (138.33) was recorded on RLC-6. All the fruit quality parameters were significantly influenced by both the rootstocks. RLC-6 and RLC-7 for Pusa Sharad; and Soh
Sarkar and RLC-7 for Pusa Round proved effective for producing larger size fruits. Except Jatti khatti for Pusa Sharad, all the rootstocks were found to produce fruits with low peel thickness in both the cultivars. The highest juice content (47.75%) in Pusa Sharad and Pusa Round (42.64%) were recorded on X-639 followed by Yama Mikan rootstocks. Pusa Sharad (9.17°B) and Pusa Round (9.20°B) had higher TSS on Jatti khatti and Yama Mikan rootstocks, respectively.
Developing soil nutrient profile of Darjeeling mandarin orchards: Soil samples were collected from different blocks of Kalimpong district in West Bengal. The pH ranged from 5.50 to 4.60, EC from 0.28 to 0.10, OC from 2.20 to 0.78%, N from 585.30 to 115.80 kg/ha, available phosphorus from 80 to 25 kg/ha, K ranged 285.00 to 90.00 kg/ha, B ranged from 0.97 to 0.11 ppm, Fe from 0.20 to 0.262 ppm, S from 0.07 to 0.35 ppm, Zn 0.10 to 0.11 ppm, Mn 11.19 to 6.00 ppm, and Cu 0.99 to 0.36 ppm. Interpretation of data would help in analyzing the decline in nutrient status in Darjeeling mandarin orchards.
Identifying causes of decline in Darjeeling mandarin:
The study was undertaken with the objectives to assess reasons for decline in mandarin orchards by perceiving constraints of the growers. Ranking was given based on the severity of decline, the study shows that lack of quality planting material for re-plantation was ranked I and increased incidence of disease specifically viral diseases like CTV and bacterial disease like Citrus Greening was ranked II. These were the major reasons for citrus decline.
2.2.6.5 Grape
Two elicitors, viz., methyl jasmonate (MeJA) and benzothiadiazole (BTH) were used to improve the bioactive compounds in the cv. Pusa Navrang.
Higher concentration of methyl jasmonate (10 and 15 mM) elicited better accumulation of total phenolics, total flavonoids, total monomeric anthocyanins and antioxidant (DPPH, FRAP and CUPRAC assays) activities. Similarly, application of 0.4 mM BTH at veraison stage as well as 3 day after it improved the
berry qualities. However, quality parameters like total soluble solids, titratable acidity, pH and ascorbic acid contents along with the morpho-physical bunch properties of grape were least affected.
In an another study, bio-regulators & micronutrient namely, ethephon, abscisic acid and boric acid improved berry quality in grape genotypes, namely, Flame Seedless, Pusa Aditi and Pusa Swarnika.
Ethephon at 400 ppm followed by ABA (200 ppm) were found effective for ‘Flame Seedless’ improving berry colour and quality, while boric acid (0.4%) for Pusa Swarnika and ethephon (300 ppm) for Pusa Aditi were most effective.
Effect of rootstocks on wine grape production:
Grape cv. Syrah grafted on seven inter-specific grape rootstocks, namely, SO4, 110R, P1103, 140Ru, P1103, Fercal, 3309C and 41B were studied for their stionic influence. Syrah on P1103 produced berries having the earliest maturity, significantly longer bunches (length
& width; 14.17 and 8.90 cm) as well as the highest yield (9.26 kg vine-1). This rootstock also resulted in the maximum total phenols (158.43 mg 100 ml-1 GAE) and total flavonoids (83.5 mg 100 ml-1 QE) in berries, while rootstock 110 R induced the highest quantity of total phenols (298.60 mg 100 g-1 GAE) and flavonoids (14.48 mg g-1 QE) in leaves with very dense trichome, thus, imparting biotic stress resistance. This rootstock also produced the highest berry TSS (22.260Brix) and total monomeric anthocyanins (406 mg 100 g -1) with low acidity (0.40%).
2.2.6.6 Kinnow
Kinnow mandarin exhibits poor flavedo-colour at harvest in National Capital Region. The efficacy of different concentrations and timings of spray of inhibitors of gibberellin biosynthesis such as prohexadione calcium (Pro-Ca) was investigated.
Pro-Ca at 300 ppm resulted in decreased hue angle and increased fruit colour index and total carotenoids (38.3 mg kg⁻¹) in the flavedo, besides, fruit quality traits like TSS (10.120B), titratable acidity (0.79%) and ascorbic acid content (21.22 mg/100 g). The maximum
carotenoids content in juice (310 µg/100 ml) and peel (688 µg/100 ml) were recorded due to 300 ppm Pro-Ca.
Guava canopy management: Eight commercially prominent guava varieties from different growing regions, viz. Hisar Safeda, Thai Guava, Allahabad Safeda, Sardar (L-49), Lalit, Punjab Pink, Pant Prabhat and Shweta have been established at close spacings of 3x3 m and 4 x 4 m to standardize ideal plant canopy for intensive production. The canopy volume was recorded maximum in Punjab Pink and minimum in Thai Guava in 4 x 4 and 3 x 3 m spacings. Flowering was earliest in Shweta followed by Lalit and Allahabad Safeda. Maximum number of flowers/branch was recorded in Punjab Pink (37) followed by Shweta (33) and Sardar (27). The highest number of fruits was recorded in Punjab Pink (156.67 and 148.00) in 4x4 and 3 x 3 m spacings, respectively. Fruit weight was highest in Thai Guava followed by Pant Prabhat.