Development of male lines

Abstract

2.6. Development of male lines: It is simultaneous to the development of varieties in castor. The main objectives were to develop early or medium duration (150 days), short to medium tall, high oil, high seed yield and diverse inbreds with resistance to wilt complex and insect pests. Crossing programme between pistillate x male, male x male, pistillate x germplasm and male x germplasm accessions was done either in single, double, triple or back cross followed by pedigree method of selection. Two major gaps were identified during the course of the research work and rectified by taking suitable corrective measures. • Introduced a systematic planning for male line development: A common set of crosses were used to develop both female and male lines leading to the lack of genetic diversity between parental lines. Special emphasis is now laid in selection of parents for crossing programme, pedigree of the parents and enhancing diversity through diallel and multiple crossing programme. • Developed selection criteria for male lines: Emphasis on wilt resistance alone led to the gradual loss of yield contributing genes. Simultaneous selection for high seed yield, yield components and wilt resistance is practiced now. • Selection for male lines was done as a part of varietal breeding programme leading to the development of male lines with high pistillate expression. Seed setting in seed production plots was low either due to the insufficient pollen or poor pollen shedding as observed in DCS-9, male line of DCH-177. Introduced the selection criteria for selection of male lines like the number of whorls of male flowers on the spike, pollen shedding, viability etc.