Mapping QTL controlling maize deep-seeding tolerance-related traits and confirmation of a major QTL for mesocotyl length

Abstract

Deep-seeding tolerant seeds can emerge from deep soil where the moisture is suitable for seed germination. Breeding deep-seeding tolerant cultivars is becoming increasingly important in arid and semi-arid regions. To dissect the quantitative trait loci (QTL) controlling deep-seeding tolerance traits, we selected a tolerant maize inbred line 3681-4 and crossed it with the elite inbred line-X178 to generate an F(2) population and the derivative F(2:3) families. A molecular linkage map composed of 179 molecular markers was constructed, and 25 QTL were detected including 10 QTL for sowing at 10 cm depth and 15 QTL for sowing at 20 cm depth. The QTL analysis results confirmed that deep-seeding tolerance was mainly caused by mesocotyl elongation and also revealed considerable overlap among QTL for different traits. To confirm a major QTL on chromosome 10 for mesocotyl length measured at 20 cm depth, we selected and self-pollinated a BC(3)F(2) plant that was heterozygous at the markers around the target QTL and homozygous at other QTL to generate a BC(3)F(3) population. We found that this QTL explained more phenotypic variance in the BC(3)F(3) population than that in the F(2) population, which laid the foundation for fine mapping and NIL (near-isogenic line) construction.

Quantitative Trait Locus Analysis for Deep-Sowing Germination Ability in the Maize IBM Syn10 DH Population

“…Furthermore, total 11 clusters were found across both growing conditions and overlapping QTL loci were consistent with significant correlations between different germination-related traits (Supplementary Table 3). Similar results were obtained in previous studies (Tommasini et al, 2008; Zhao et al, 2010; Zhang et al, 2012). …”

“…In contrast, one QTL for mesocotyl length ( qSGML6-1 ) was found to locate near the centromere of chromosome 6 under the standard-germination condition. Recent studies at two sowing depths of 10 and 20 cm revealed 25 QTL for four traits including mesocotyl length, coleoptile length, seedling length, and germination rate in two parents of X178 and 3681-4 (Zhang et al, 2012). However, no QTL was found on chromosome 5 or 9, contrary to our findings.…”

“…Although several QTL for deep-sowing tolerance-related traits in maize have been identified (Zhang et al, 2012), questions regarding their effects remain unresolved owing to the utilization of low density of molecular markers and limited population sizes. Recent advances in next-generation sequencing technologies provide an effective platform for detection of high-quality single nucleotide polymorphism (SNP) markers for genotyping of mapping populations (Varshney et al, 2009; Wang et al, 2015; Raihan et al, 2016).…”

Mapping and characterization of quantitative trait loci for mesocotyl elongation in rice (Oryza sativa L.)

“…These results clearly demonstrated the existence of QTLs controlling mesocotyl elongation on chromosomes 1 and 3. Previous studies identified a QTL for mesocotyl length in a putatively homeologous location on the long arm of maize chomosome 3 (Troyer [1997]; Zhang et al [2012]). Troyer ([1997]) found three regions on chromosome 3, 6 and 9 related to mesocotyl elongation using translocation tester stocks.…”

“…Troyer ([1997]) found three regions on chromosome 3, 6 and 9 related to mesocotyl elongation using translocation tester stocks. Three QTLs for mesocotyl length were commonly detected on chromosome 1, 3 and 10 under two different sowing depth conditions in maize (Zhang et al [2012]). While the resolution of the maize QTL was low, the positional correspondence raises the possibility that this locus may be involved in controlling mesocotyl length in both rice and maize (Wei et al [2007]; Soderlund et al [2011]http://www.symapdb.org).…”