Identification of heterotic loci associated with grain yield and its components using two CSSL test populations in maize

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.

Overdominance is the major genetic basis of lint yield heterosis in interspecific hybrids between G. hirsutum and G. barbadense

“…Our speculation that ODO is associated with yield QTLs in cotton interspecific ILs was supported by a similar trend reported in various groups of traits in corn (Wang et al 2016), tomato (Semel et al 2006) and rice (Zhou et al 2012;Goff and Zhang 2013;Tao et al 2016). For example, Lu et al (2003) analysed four traits in two corn backcross populations.…”

Heterotic loci identified for maize kernel traits in two chromosome segment substitution line test populations

“…Many HL detected for grain yield and its components in a previous study 50 , as well as HL for kernel traits located on common chromosomal regions in the same test populations have been found on the same chromosomal region. For example, in the CSSLs × Xun9058 population, HL hlEL1a for ear length, hlEW1b for ear width, hlGY1a for grain yield, and hKW1a for kernel width were detected on umc1403-umc1397-bnlg182.…”

“…In a previous study, Wang et al . 50 identified 169 HL associated with grain yield and its five components using two test populations. Additionally, we identified several common HL of kernel-related traits over the same and overlapping introgression region lines.…”

“…Additionally, some single heterozygous CSSLs were also selfed, and 84 were selected from the BC 4 F 3 population. Finally, we achieved a population of 184 CSSLs with a single segment of donor parent Chang7-2 in the recipient parent lx9801 background 50 .…”

“…Heterotic genes usually have different genetic effects and phenotypes when heterozygosis with different alleles is observed 50 . We identified HL for kernel-related traits and compared the significance between single hybrids and the average value of two adjacent corresponding CK (hybrids Zheng58 × lx9801 or Xun9058 × lx9801).…”