Genetic Variance, Heritability and Number of Effective Genes for Spike Characters in Castor (Ricinus communis L.)

Abstract

Adequate information on genetic variance and nature of gene actions for yield component characters are very crucial for a successful breeding programme. In this study, genetic variance, heritability and number of effective genes were estimated for Some Spike Characters in Castor. Bi-parental crosses were made among six castor lines at the National Cereals Research Institute (NCRI), Badeggi, Nigeria. Forty five (45) plant samples of parents and F1, 120 F2 and 60 BC1 and BC2 of the three crosses were evaluated for estimation of the genetic variance, heritability and number of effective genes for the traits studied. The results revealed significant variability among the generations for the genetic analysis. The results showed that the magnitude of the environmental variance for all the traits in all the crosses was lesser than both additive and dominance variances except for the number of capsules per raceme in the Cross II. High heritability (h2> 60%), high magnitude of additive variance compared to dominance, high genetic advance (GA > 20%) were observed for total raceme length in all the crosses. Predominant dominance variance, low heritability and moderate average genetic advance (17.69%) were recorded in the crosses for the seed yield per plant. Number of capsules per raceme (CPR) was controlled by 4.47 to 20.96 genes among the crosses. Seed weight (SW) was controlled by a range of 3.13 to 25.16 effective genes. For seed yield (SY), a range from 27.50 to 52.29 effective genes was observed. These findings provide a guide on choice of selection procedures for the improvement of the traits studied.