Diallel analysis of yield and days to first harvest of baby corn

Genetics of yield and days to first harvest in baby corn were studied in a 9x9 diallel cross. Combining ability analysis by Griffing's method indicated significance of both additive and non-additive effects. The relative importance of additive gene action and dominance gene action measured by ratio of 2V sub(g)/(2V sub(g)+V sub(s)) for yield and days to first harvest were 0.405 and 0.459, respectively. Reciprocal effects were not significant for either character. For Hayman's method of analysis the array values for Wr-Vr for yield and days to first harvest were homogeneous across parental arrays, indicating the lack of epistasis. Regression of Wr on Vr for yield and days to first harvest gave regression coefficients of 0.79 and 0.98, respectively. The regression coefficients were not significantly different from 1.0 but were significantly different from 0.0, confirming the Wr-Vr analysis. Estimates of genetic component of variation and genetic parameters for yield following Hayman's method showed significant additive (D) and dominant gene action (h sup(2)). Degree of dominance for yield as revealed by Wr/Vr graph was overdominance, while the average degree of dominance as calculated from (H1/D) sup 1/2 was within the range of incomplete dominance. The correlation between Wr+Vr and parental value, Yr, was negative for yield, indicating that the parent containing most increasing genes had the lowest value of Wr+Vr, and thus contained most dominant genes. Both additive and dominance gene actions are important for the genetic variation of days to first harvest. The degree of dominance for this character as revealed by the ratio (H1/D) sup(1/2) was 0.92 showed incomplete dominance, which confirmed the Wr/Vr graphical analysis. Correlation between Wr+Vr and parental value, Yr, was positive for days to first harvest, implying that the gene with increasing value was recessive (earliness was dominant to lateness). Estimation of the number of groups of gene, or number of loci exhibiting dominance suggeste that about 11 groups of genes controlling yield and about two groups of gene controlling days to first harvest. Narrow-sense heritabilities estimated for yield and days to first harvest were 0.28 and 0.56, respectively.