Division of Genetics, Indian Agricultural Research Institute, Delhi-12
Considering grain yield and response to nitrogen levels as measures of fitness, the question of hybrids vs. varieties in grain sorghum is examined in relation to the environmental conditions and some of the available findings on fitness of heterozygotes and homozygotes in self-fertilized species. The performance with respect to grain yields and response to nitrogen levels of a commercial sorghum hybrid CSH-1 and an improved variety 413 indicated that the hybrid and the variety were comparable in both respects.
Further, in more favourable environments, as reflected by higher mean yields, the variety was superior while in locations where the yield levels are generally low, obviously on account of moisture stress and other unfavourable environmental conditions, the commercial hybrid CSH-1 was superior. Capitalizing on heterozygote advantage is, therefore, expected not only to provide the genetic means to raise the low yields of some of the rainfed tracts but could also stabilize production levels.
