Research overview: Implications of research findings for
secondary traits. Segregation analyses were conducted on F2 populations to determine the resistance to susceptibility phenotypic ratios.
Significant findings were made in the participatory rural appraisal and the participatory variety selection studies with small-scale farmers and buyers, the evaluation of pigeonpea genotypes, the development of a new wilt screening technique and the inheritance studies on Fusarium wilt resistance. The findings include the following:
a) Farmers perceived Fusarium wilt as the most prevalent and devastative disease of pigeonpea and yet very little was being done to manage it.
b) Pigeonpea production is constrained by many factors such as poor soil fertility, flower abortion, poor weather conditions, lack of certified seed for improved cultivars, insect pests, and diseases.
c) Most local pigeonpea landraces were susceptible to Fusarium wilt and yet they accounted for more than 80% of the total pigeonpea production in the country.
d) Local landraces were preferred by farmers, despite the release of Fusarium wilt resistant varieties, because of taste (flavour) and fast cooking time which are lacking in the released varieties.
e) The local landraces were, however, mostly late maturing, low yielding with few seeds per pod.
f) Farmers and buyers were able to select ten promising pigeonpea landraces with desirable traits through participatory variety selection. These lines were used as parents in the breeding programme to develop Fusarium wilt resistant lines with farmer- and consumer preferred traits.
g) During genotype evaluation, some local landraces were identified with inherent resistance to wilt, high yielding ability, and early maturity. AP10, a local landrace, gave an outstanding performance. It is high yielding, Fusarium wilt resistant, large-seeded, and early maturing. It is highly preferred by farmers and consumers because of these traits.
h) The infested seed inoculation technique development is effective in screening pigeonpea germplasm for resistance to wilt. Wheat grains showed to be the best medium for multiplying F. udum and for easy inoculation compared to
sorghum and finger millet. The pathogen can be preserved in double sterile distilled water, PDA slants, or silica gel for more than 2.5 years.
i) Significant negative GCA effects for wilt resistance, days to 50% flowering and plant height were identified in the local landraces as were positive GCA effects for seed per pod, and number of secondary branches.
j) Significant negative SCA effects were also identified for wilt resistance and days to 50% flowering.
k) Inheritance studies showed that resistance to wilt was dominant over susceptibility in most F1 crosses. Most F1 crosses were resistant to Fusarium wilt which was due to both additive and non-additive gene effects.
l) The Chi-square analyses gave 3:1, 13:3, 15:1 and 9:7 (resistant: susceptible) segregation ratios, except for a few crosses which could not be fitted into any known segregation ratio at F2 generation.
The implications of these findings, with regard to the management of Fusarium wilt and breeding for yield and yield components in pigeonpea, are far-reaching. Firstly, it would be easy to convince farmers to deploy new approaches to managing Fusarium wilt in their fields because they are aware of the disease and its damaging effects. Such approaches would include the use of resistant varieties, the use of certified seed, rotation, physically removing diseased plants and intercropping pigeonpea with crops non-host to F. udum, for example, sorghum. This would be aimed at reducing inoculum in the soil to below threshold levels.
The many pigeonpea production problems call for a multidisciplinary approach towards helping farmers to improve pigeonpea production. Scientists from different disciplines should work together and address farmers’ problems.
There is a need to breed for Fusarium wilt resistant varieties with farmer- and consumer- preferred traits. The fact that local landraces account for a high percentage of pigeonpea production is a positive indicator that any variety with farmer-preferred traits would have a high adoption rate. Therefore, the continued involvement of farmers in the whole crop improvement programme is very important.
The fact that farmers and traders prefer local landraces is a “wake up call” for pigeonpea breeders not to ignore consumers’ demands in the breeding programme. Some traits that may not be related to yield, such as taste/flavour and cooking time, play a vital role in the whole varietal adoption process. Breeders should appreciate the importance of involving farmers in the whole breeding programme from variety selection to selection for desirable traits in the filial generations for additional reasons. The involvement of farmers or consumers in the variety selection process empowers them and gives them a sense of recognition, responsibility, and ownership for the varieties to be developed. Farmers look forward to the upcoming varieties because they feel they are part of the process.
Farmers also prefer high yielding and early maturing varieties. The breeding process should concentrate on selecting for such factors as early flowering, optimum branches per plant, more seeds per pod, and large-seed size in pigeonpea lines.
The results of the evaluation of local landraces for wilt, yield and other traits showed the existing potential in the local germplasm for the selection of potential landraces with desirable traits for genetic improvement. The farmers’ selection of promising landraces is an assurance of a high adoption rate of the resultant cultivars after incorporating the missing traits.
The answers to farmers’ problems mostly lie within reach, only that farmers do not know how to find solutions. This is evidenced by the outstanding performance of AP10. It is a local landrace with many desired attributes that farmers prefer, such as early maturity, large-seeds, high yield and Fusarium wilt resistance. This is a lesson to breeders as well, that they should first exploit the available resources before introducing foreign materials or make crosses between landraces with imported germplasm with desirable traits such as Fusarium wilt resistance.
Screening of pigeonpea and filial generations can be enhanced through the use of a newly developed screening technique which uses locally available materials.
Preservation, multiplication and inoculation of the isolates can easily be done even in resource-strapped laboratories. The isolate can be preserved at room temperature in double sterilised distilled water. Wheat, sorghum and finger millet are crops that are grown in most African countries and their availability is guaranteed. The quantification of