Heritability Estimates for Seed Yield and Its Components in Cynodon Dactylon Var. Dactylon (L.) Pers.

Abstract

Seed yield is a major trait targeted for improvement in bermudagrass [Cynodon dactylon var. dactylon (L.) Pers.] breeding programs because of the increased interest in seed-propagated cultivars.  Understanding the nature of genetic variation for seed yield and its components in bermudagrass would aid development of seed-propagated bermudagrass cultivars. The objective of this study was to estimate the genetic component of variation and narrow-sense heritability for seed yield and its two major components, inflorescences prolificacy and seed set percentage in bermudagrass. Twenty-five half-sib families and their respective clonal parents were evaluated at two Oklahoma locations, Perkins and Stillwater in 2012 and 2013. Half-sib families were different for seed yield, inflorescences prolificacy and seed set percentage, indicating the expression of additive genes in controlling these traits. Family × location effects were observed for seed set percentage and seed yield.  All three traits showed family × year interaction effects. There was a significant family × location × year interaction in inflorescences prolificacy and seed set percentage. Narrow-sense heritability estimates for seed yield was 0.18 based on variance component analysis among half-sib families and ranged from 0.26 to 0.68 based on parent-offspring regressions, indicating a complex genetics of seed yield. Heritability estimates were moderate (0.30-0.55) for inflorescences prolificacy and moderate to relatively high (0.41-0.78) for seed set percentage. These results indicate that sufficient magnitudes of additive genetic variation for seed set percentage and inflorescence prolificacy permit positive response to selection and conventional progeny-based genotypic evaluation is necessary for seed yield improvement.