Abstract
Heterosis has widely been used to increase grain yield and quality. In this study, the genetic basis of heterosis on grain yield and its main components in maize were examined over 2 years in two locations in two test populations constructed from a set of 184 chromosome segment substitution lines (CSSLs) and two inbred lines (Zheng58 and Xun9058). Of the 169 heterotic loci (HL) associated with grain yield and its five components identified in CSSL × Zheng58 and CSSL × Xun9058 test populations, only 25 HL were detected in both populations. The comparison of quantitative trait loci (QTLs) detected in the CSSL population with HL detected in the two test populations revealed that only 15.46% and 17.35% of the HL in the given populations respectively, shared the same chromosomal regions as that of the corresponding QTLs and showed dominant effects as well as pleiotropism with additive and dominant effects. In addition, most of the HL (74.23% and 74.49%) had overdominant effects. These results suggest that overdominance is the main contributor to the effects of heterosis on grain yield and its components in maize, and different HL are associated with heterosis for different traits in different hybrids.
Highlights
Genes[36,37,38,39] and gene dosages on heterosis[40,41,42] have been reported in previous studies
Heterotic loci (HL) associated with grain yield and its major components were studied in two test populations constructed from a chromosome segment substitution lines (CSSLs) population and two test inbred lines through comparison of each single test cross with its corresponding hybrid (CK)
The objectives of this study were (1) to detect the HL underlying grain yield and its components, (2) to compare the identified HL associated with grain yield and its components between different test populations, and (3) to analyse the genetic basis of heterosis for grain yield and its components in maize
Summary
Genes[36,37,38,39] and gene dosages on heterosis[40,41,42] have been reported in previous studies. Tang et al.[51] have reported that dominance effects of HL at the single-locus level as well as AD interactions play an important role in the genetic basis of heterosis for grain yield and its components in the maize hybrid Yuyu[22]. HL associated with grain yield and its major components were studied in two test populations constructed from a CSSL population and two test inbred lines through comparison of each single test cross with its corresponding hybrid (CK). The objectives of this study were (1) to detect the HL underlying grain yield and its components, (2) to compare the identified HL associated with grain yield and its components between different test populations, and (3) to analyse the genetic basis of heterosis for grain yield and its components in maize
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