Partial Dominance, Overdominance and Epistasis as the Genetic Basis of Heterosis in Upland Cotton (Gossypium hirsutum L.)

Abstract

Determination of genetic basis of heterosis may promote hybrid production in Upland cotton (Gossypium hirsutum L.). This study was designed to explore the genetic mechanism of heterosis for yield and yield components in F2: 3 and F2: 4 populations derived from a hybrid ‘Xinza No. 1’. Replicated yield field trials of the progenies were conducted in 2008 and 2009. Phenotypic data analyses indicated overdominance in F1 for yield and yield components. Additive and dominance effects at single-locus level and digenic epistatic interactions at two-locus level were analyzed by 421 marker loci spanning 3814 cM of the genome. A total of 38 and 49 QTLs controlling yield and yield components were identified in F2: 3 and F2: 4 populations, respectively. Analyses of these QTLs indicated that the effects of partial dominance and overdominance contributed to heterosis in Upland cotton simultaneously. Most of the QTLs showed partial dominance whereas 13 QTLs showing overdominance in F2:3 population, and 19 QTLs showed overdominance in F2:4. Among them, 21 QTLs were common in both F2: 3 and F2: 4 populations. A large number of two-locus interactions for yield and yield components were detected in both generations. AA (additive × additive) epistasis accounted for majority portion of epistatic effects. Thirty three complementary two-locus homozygotes (11/22 and 22/11) were the best genotypes for AA interactions in terms of bolls per plant. Genotypes of double homozygotes, 11/22, 22/11 and 22/22, performed best for AD/DA interactions, while genotype of 11/12 performed best for DD interactions. These results indicated that (1) partial dominance and overdominance effects at single-locus level and (2) epistasis at two-locus level elucidated the genetic basis of heterosis in Upland cotton.

Using yield quantitative trait locus targeted SSR markers to study the relationship between genetic distance and yield heterosis in upland cotton (Gossypium hirsutum)

“…The results in this study showed that hybrid performance was much superior to that of the parental inbred lines even in different environments. These findings are in line with those of previous reports (Liang, Shang, Wang, & Hua, ; Rauf, Khan, & Nazir, ; Zhu et al, ). However, the intraspecific hybrids in the present study showed variation in the degree of heterosis for all traits in different environments.…”

Mapping QTLs for drought tolerance in an F2:3 population from an inter-specific cross between Gossypium tomentosum and Gossypium hirsutum

“…Previous studies have implicated an OD genetic effect in playing an important role in the genetic control of heterosis in rice and QTLs with OD genetic effects have been reported to be common in the rice genome (Zhuang et al, 2001). Analyses of QTLs for yield and yield components in cotton indicated that the effects of PD and OD simultaneously contributed to heterosis in upland cotton (Liang et al, 2015). Hence, QTLs with PD and OD effects may play an important role in the development of drought tolerant hybrid cotton varieties that are tolerant to drought stress through conventional and male sterility methods.…”

QTL and genetic analysis controlling fiber quality traits using paternal backcross population in Upland Cotton

“…It is very important to detect novel QTLs and to validate the reported QTLs using diverse populations. In our previous study, serial genetic analyses were performed in multiple segregating populations including F 2 , F 2: 3 , RIL and BC/M population derived from the hybrid ‘Xinza 1’ across multiple years and various locations (Liang et al 2013; Liang et al 2015; Shang et al 2015, 2016a,b,c,d; Ma et al 2017, 2018a, 2019). In previous study, 111 quantitative trait loci (QTLs) were detected for fiber quality using four populations derived from RIL (XZ) and backcross (XZV) hybrids (Shang et al 2016d).…”