Comparative Genetic Analysis of Lint Yield and Fiber Quality among Single, Three‐way, and Double Crosses in Upland Cotton

Abstract

Appropriate crossing systems for genetic improvement of quantitative traits are critical in cotton breeding. Determination of genetic variance for lint yield and fiber quality in three different crossing schemes (single cross [SC], three‐way cross [TWC], and double cross [DC]) of upland cotton (Gossypium histutum L.) will help breeders decide which crossing scheme to use in hybrid production and pure‐line development. This study was designed to compare agronomic performance and fiber quality among SCs, TWCs, and DCs and determine genetic variance for evaluated traits in the three crossing systems. A balanced set of 10 F2 hybrid populations from each crossing system was planted with their five parents in 2013, 2014, and 2015. There were no significant differences for lint yield and fiber properties between SC and the other two crossing systems. When genetic variance components were expressed as proportions of the total phenotypic variances (VP), there were mainly dominance (VD) and environmental variances (VE) for lint yield in F2 hybrids of all three crossing systems. The predominance of VD for lint yield suggests that selection would be more successful in later generations than in early generations among lines derived from SCs, TWCs, and DCs. The proportion of dominance (VD/VP) and additive genetic variances (VA/VP) for yield components was greater in TWCs and DCs than in SCs. Midparent heterosis (MPH) of lint yield in TWCs increased compared with SCs. Results indicate that TWCs may be used to enhance heterosis in hybrids, and TWCs and DCs may be used in pure‐line development to increase yield potential of upland cotton cultivars.