Genetic Variances in a Synthetic Variety of Maize Estimated by Two Mating Designs1
- J. C. Sentz2
Genetic parameters for a synthetic variety of maize (Zea mays L.) were estimated from Design I (D-I) Design II (D-11) matings. Corn borer and stalk rot resistance selection in derivation of lines had no effect upon mean yield or other traits in the D-II reconstituted population.
Additive variance was significant with both designs and of primary importance for all traits. Dominance variance contributed 45% of the genetic variance for yield, but was relatively unimportant for other traits. Greater additive variance estimates with D-II indicate some epistasis may exist for height and days to tassel. However, additive estimates were less with D-II for yield, ear moisture, and ear diameter.
Genotype-environment interactions were important for yield and ear moisture, but no consistent rdationships with their respective genetic components were obtained. In the absence of first-order genotype interactions with years and locations, I pooled the interaction mean squares for D-I analysis.
D-I was less sensitive than D-II for estimating genetic variances, particularly dominance variance. Although variance estimates were not large, expected yield increase with half-sib progeny selection was 6.1 to 8.6%.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
Copyright © . .