Epistasis for Vegetative and Reproductive Traits in Peanut
- Hari D. Upadhyaya and
- Shyam Nigam
Most genetic models assume absence of epistasis while estimating components of genetic variation. However, epistasis when present introduces bias. These biased estimates affect the progress in a breeding program since they influence the choice of breeding methodology. The objectives of this study were to determine the significance of epistasis in the inheritance of pod yield and related traits in 15 peanut (Arachis hypogaea L.) cultigens, and to estimate the additive and dominance variances for the traits not influenced by epistasis. Two cultigens and their F1 hybrid were each crossed to 15 cultigens from 13 countries, representing three botanical groups. The experiment was conducted in the 1992-1993 post-rainy and 1993 rainy environments at the ICRISAT Asia Center, Patancheru, India. The deviations were analyzed to detect epistasis of 11 traits. Epistasis affected the expression of eight traits in both environments. Environments interacted more strongly with epistatic gene actions than with additive or dominance gene actions. Expression of epistasis was influenced by genotypes and environments, indicating the need for more genotypes and environments for effective detection of epistasis. Evidence for additive genetic variance and lower levels of partial dominance for canopy breadth and additive and dominance variances and complete dominance for shelling outturn was obtained in the post-rainy environment.
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