Selection gain and interrelations between agronomic traits in wheat F5 genotypes

ABSTRACT This work aimed to estimate the variance components and genetic parameters, the selection gain, and the cause and effect relationships among traits in order to identify important traits for direct and indirect selection of wheat (Triticum aestivum L.) lines. Three strategies were used to obtain selection gains: direct and indirect selection, an index based on “ranks,” and the Smith and Hazel index. In the 2017 crop season in Brazil, 420 wheat lines from the F5 generation were conducted in families with intercalary controls. High heritability of spike weight, number of kernels, and total kernel weight resulted in the best direct selection gains. The selection of plants with a high number of tillers resulted in grain yield improvement. The use of selection indexes is important in advanced wheat lines; they promote genetic gains distributed among agronomic traits.

摘要 本研究旨在估算方差组分与遗传参数、选择增益以及性状间的因果关系，以期筛选出可用于普通小麦（Triticum aestivum L.）品系直接选择与间接选择的重要性状。本研究采用三种策略获取选择增益：直接选择与间接选择、基于"秩值"的选择指数以及史密斯-黑兹尔选择指数（Smith and Hazel index）。2017年巴西种植季中，420个F5代小麦品系以间隔种植对照的方式组建家系开展田间试验。穗重、每穗粒数以及籽粒总重均具有较高遗传力，可实现最优的直接选择增益。筛选分蘖数较多的植株可提升籽粒产量。在高级代小麦品系选育中应用选择指数至关重要，可促使农艺性状间均衡实现遗传增益。