Diallel analysis and inbreeding depression in agronomic and technological traits of cotton genotypes

Luiz Paulo De Carvalho,Leonardo Lopes Bhering,Josiane Isabela Da Silva Rodrigues,Francisco José Correia Farias,Paulo Eduardo Teodoro

doi:10.1590/1678-4499.2017336

Abstract

ABSTRACT Cotton provides about 90% of the world textile fiber, and is one of the crops of greater industrial relevance. The objectives of this study were to estimate the inbreeding depressionand the genetic effects involved in the control of the agronomic andfiber quality traits in F1 and F2 generations and to identify promising hybrids for obtaining superior cotton genotypes. Two cultivars of upland cotton and two moco (Brazilian endemic) cotton were crossed using a half-diallel scheme. The following traits were evaluated: percentage of fibers and weight of one boll, fiber length, fiber uniformity, short fiber index, fiber strength, and micronaire index. The additive genetic effects are predominant in the evaluated agronomic and fiber quality traits. Cultivar FM 966 is the most suitable parent to compose crossing blocks for the improvement of cotton agronomic and fiber quality traits. The hybrids FM 966 × CNPA 7MH and FM 966 × BRS 286 are the most promising for obtaining segregating populations aiming to select superior genotypes. Inbreeding depression is more pronounced in the agronomic traits than in the fiber quality traits.

Highlights

Cotton (Gossypium hirsutum L.) provides about 90% of the world textile fiber, and is one of the crops of greater industrial relevance
The diallel scheme is a genetic design developed by Griffing (1956) that enables the breeder to know information regarding the behavior of the parents between each other, denominated general combining ability (GCA), which is attributed to genes with additive effects; and specific combining ability (SCA), which is attributed to non-additive effects of their hybrid combinations
There were significant differences among the twelve treatments for all traits, except for UNIF and short fiber index (SFI) (Table 1). These results indicate the presence of genetic variability between treatments, and the possibility of selecting superior genotypes with the advance of segregating generations

Summary

Introduction

Cotton (Gossypium hirsutum L.) provides about 90% of the world textile fiber, and is one of the crops of greater industrial relevance. It is cultivated in more than 30 million hectares, in more than 90 countries in the temperate, subtropical and tropical region in the world (Panni et al 2012). The main objective of breeders is to develop cotton cultivars with high yield and quality of fiber for processing in the textile industry. The efficient choice of the parents and the selection of the best hybrid combinations increase the chances of obtaining a successful breeding program (Queiroz et al 2017). The diallel scheme is a genetic design developed by Griffing (1956) that enables the breeder to know information regarding the behavior of the parents between each other, denominated general combining ability (GCA), which is attributed to genes with additive effects; and specific combining ability (SCA), which is attributed to non-additive effects of their hybrid combinations

Objectives

Methods

Results

Conclusion