Abstract
BackgroundMaize (Zea Mays L.) is one of the most important cereal crops worldwide and provides food for billions of people. Stalk lodging can greatly undermine the standability of maize plants and therefore decrease crop yields. Rind penetrometer resistance is an effective and reliable method for evaluating maize stalk strength, which is highly correlated with stalk lodging resistance. In this study, two recombinant inbred line populations were constructed from crosses between the H127R and Chang7-2 lines, and between the B73 and By804 lines. We genotyped these two populations and their parents using 3,072 single nucleotide polymorphism markers and performed phenotypic assessment of rind penetrometer resistance in multiple environments to dissect the genetic architecture of rind penetrometer resistance in maize.ResultsBased on two linkage maps of 1,397.1 and 1,600.4 cM with average interval of 1.7 and 2.1 cM between adjacent makers, respectively, seven quantitative trait loci (QTL) for rind penetrometer resistance were detected in the two recombinant inbred line populations. These QTL were distributed in seven genomic regions, and each accounted for 4.4–18.9% of the rind penetrometer resistance variation. The QTL with the largest effect on rind penetrometer resistance, qRPR3-1, was located on chromosome 3 with the flanking markers PZE-103123325 and SYN23245. This locus was further narrowed down to a 3.1-Mb interval by haplotype analysis using high-density markers in the target region. Within this interval, four genes associated with the biosynthesis of cell wall components were considered as potential candidate genes for the rind penetrometer resistance effect.ConclusionsThe inheritance of rind penetrometer resistance is rather complex. A few large-effect quantitative trait loci, together with a several minor-effect QTL, contributed to the phenotypic variation in rind penetrometer resistance in the two recombinant inbred line populations that were examined. A potential approach for improving stalk strength and crop yields in commercial maize lines may be to introgress favorable alleles of the locus that was found to have the largest effect on rind penetrometer resistance (qRPR3-1).
Highlights
Maize (Zea Mays L.) is one of the most important cereal crops worldwide and provides food for billions of people
Increased rind penetrometer resistance (RPR) shows a high correlation with stalk-lodging resistance [11,12,13,14,15] and this method has been widely applied in estimating stalk lodging resistance potential in maize [2,16,17,18] and in breeding maize hybrids that are highly resistant to stalk lodging [1,11,12,19,20]
Phenotypic variation in RPR Significant difference in RPR was observed between the H127R and Chang7-2 parental lines, whereas no significant difference was observed between the B73 and By804 lines (Table 1)
Summary
Maize (Zea Mays L.) is one of the most important cereal crops worldwide and provides food for billions of people. Rind penetrometer resistance is an effective and reliable method for evaluating maize stalk strength, which is highly correlated with stalk lodging resistance. Rind thickness and crushing strength have been useful in increasing lodging resistance in maize as they have shown a strong relationship with stalk lodging [7,9]. These two methods are not ideal because they require the destruction of maize stalk. Increased RPR shows a high correlation with stalk-lodging resistance [11,12,13,14,15] and this method has been widely applied in estimating stalk lodging resistance potential in maize [2,16,17,18] and in breeding maize hybrids that are highly resistant to stalk lodging [1,11,12,19,20]
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