Genetic Analysis of Primitive Cotton Germplasm Accessions

Abstract

The recent conversion of primitive cotton (Gossypium hirsutum L.) stocks to the day‐neutral flowering habit has effectively made these accessions readily available for direct use in plant breeding programs. Genetic analysis of these accessions would be useful in ascertaining parental material for improvement of specific traits. The objective of this study was to estimate genetic variances for 13 yield, fiber, and other agronomic traits in 79 accessions and 11 cultivars. A minimum norm quadratic unbiased estimation (MINQUE) method was used for estimating genetic variance components and an adjusted unbiased prediction method for predicting genetic effects. Additive × environment interaction variances were significant for lint yield and node of first fruiting branch. The additive variance components made relatively high contributions to the phenotypic variances for lint percentage and boll size. Additive variances were relatively low for other traits. Narrow‐sense heritabilities ranged from 8 to 50% for the traits studied. The proportion of accessions displaying significant, positive effects ranged from 12.7% for 50% span length to 30.4% for lint percentage and 2.5 span length. Positive additive effects for yield, lint percentage, and fiber traits except micronaire and negative effects for N1FB, NOMS, and plant height could be considered favorable effects. Although 16 of the primitive accessions showed significant positive additive effects for lint yield, only MDN‐74 and MDN‐101 could be predicted to produce stronger fiber, as well as higher lint yield and lint percentage. Results indicate that many primitive accessions may be used in crosses with commercial cultivars without serious loss of agronomic potential in the progeny.