Genetic Association between Yield and Fiber Strength in Upland Cotton1

Abstract

Genetic variances anl correlations were measured on the segregating progeny of a cross between two upland cotton (Gossypium hirsutum L.) cultivars. One cultivar (‘TH‐149‐8‐5’) had high lint yield and high fiber strength, whereas the other parental cultivar (‘Lankart 57’) had low lint yield and low fiber strength. Previous studies of genetic correlations between lint yield and fiber strength in upland cotton have shown that there is a negative association between these two traits. However, in the previous studies, high yield and high fiber strength were introduced from opposite parents in the cross. The present study was undertaken to determine if alteration of this relationship between parental means would change the observed genetic association in the progeny population. Eighty‐nine progeny families, generated by selling individual F2 plants, were evaluated in two replicates in each of three environments for lint yield, several yield components, and fiber quality indices. Population means were generally intermediate to the parental means, and significant genetic variance was found for each trait. Genotypic correlations generally agreed in both sign and magnitude with past estimates. The genotypic correlations between lint yield and the fiber quality traits were generally negative. Both 2.5% span length and fiber strength (T1) were negatively correlated with yield (both −0.36). Significance of the correlations and the expected gain from selection were discussed.