QTL Mapping in Three Connected Populations Reveals a Set of Consensus Genomic Regions for Low Temperature Germination Ability in Zea mays L.

Abstract

Improving seed vigor in response to cold stress is an important breeding objective in maize that allows early sowing. Using two cold tolerant inbred lines 220 and P9-10 and two susceptible lines Y1518 and PH4CV, three connected F2:3 populations were generated for detecting quantitative trait locus (QTL) related to seed low-temperature germination ability. At 10°C, two germination traits (emergence rate and germination index) were collected from a sand bed and three seedling traits (seedling root length, shoot length, and total length) were extracted from paper rolls. Significant correlations were found among all traits in all populations. Via single-population analysis, 43 QTL were detected with explained phenotypic variance of 0.62%∼39.44%. Seventeen QTL explained more than 10% phenotypic variance; of them sixteen (94.12%) inherited favorable alleles from the tolerant lines. After constructing a consensus map, three meta-QTL (mQTL) were identified to include at least two initial QTL from different populations. mQTL1-1 included seven initial QTL for both germination and seedling traits; with three explaining more than 30% phenotypic variance. mQTL2-1 and mQTL9-1 covered two to three initial QTL. The favorable alleles of the QTL within these three mQTL regions were all inherited from the tolerant line 220 and P9-10. These results provided a basis for cloning of genes underlying the mQTL regions to uncover the molecular mechanisms of maize cold tolerance during germination.

Quantitative trait locus mapping for seed artificial aging traits using an F2:3 population and a recombinant inbred line population crossed from two highly related maize inbreds

“…Analysed by a 6K SNP chip, 345 SNPs were polymorphic between X178 and I178, which was far less than that between some other inbred pairs where the polymorphic SNPs were approximately 1,500 (Li et al., ). Moreover, most of the polymorphic markers between X178 and I178 were located on chromosome 7 and chromosome 10 (Figure ; Supporting Information Table S2).…”

Identification of candidate genes for low temperature tolerance during germination of maize using a genome-wide association study and RNA-sequencing

“…Under these conditions, seeds normally won't germinate and the growth of seedlings will stop [1]. Thus 10℃ has normally been chosen as the growth conditions for the identification and screen of proper maize germplasm [3,4,5]. In recent years, the occurrence of cold weather becomes more uncertain and low temperature weather occurs more frequently, especially during the germination period and early developmental stage of the seedlings.…”

“…In another study, 12 QTL controlling low-temperature germination rate and primary radicle length were detected on chromosomes 4, 5, 6, 7 and using 243 lines of the intermated B73×Mo17 (IBM) Syn4 recombinant inbred line (RIL) population [11]. Later work identified 43 QTL that explained 0.62%~39.44% of phenotypic variance for low temperature seed germination in maize using three connected F2:3 populations with inbred lines of two low temperature tolerant inbred lines 220 and P9-10 and two susceptible lines Y1518 and PH4CV [5]. Several SNPs associated with low temperature tolerance traits at the seedling and seed germination stages were detected using GWAS.…”

“…Because of environmental interaction effects, two methods of evaluation, both indoor and outdoor, were used and an improved technical system was established for present study. Many performance indicators have been applied to evaluate low temperature tolerance of maize germination, such as germination potential, germination rate, germination index, radicle length and germ length [5,14]. In order to eliminate genetic background differences, the ratio of relative values of low temperature to normal temperature for various traits is usually used as an indicator to measure the strength of low temperature resistance [3].…”

A Comparative Analysis of the Hybrid Maize (Zea mays L.) Seed Quality in China from 2013 to 2018

“…The raffinose family oligosaccharides play important roles in modulating maize seed vigor and seed longevity in storage [10]. Regarding the genetics of maize seed vigor-related traits, Jiang et al (2011) detected 10 QTLs controlling coleorhiza length, which were closely related to seed vigor [11], and Li et al [12] detected 43 QTLs related to seed low-temperature germination ability in two cold-tolerant inbred lines (220 and P9-10), two susceptible lines (Y1518 and PH4CV), and three connected F2:3 populations.…”