Identifying quantitative trait loci and determining closely related stalk traits for rind penetrometer resistance in a high-oil maize population

Abstract

Stalk lodging in maize causes annual yield losses between 5 and 20% worldwide. Many studies have indicated that maize stalk strength significantly negatively correlates with lodging observed in the field. Rind penetrometer resistance (RPR) measurements can be used to effectively evaluate maize stalk strength, but little is known about the genetic basis of this parameter. The objective of this study was to explore a genetic model and detect quantitative trait loci (QTL) of RPR and determine relationships between RPR and other stalk traits, especially cell wall chemical components. RPR is quantitative trait in nature, and both additive and non-additive effects may be important to consider for the improvement of RPR. Nine additive-effect QTLs covering nine chromosomes, except chromosome 5, and one pair of epistatic QTLs were detected for RPR. CeSA11 involved in cellulose synthesis and colorless2 involved in lignin synthesis were identified as possible candidate genes for RPR. Internode diameter (InD), fresh weight of internode (FreW), dry weight of internode (DryW), fresh weight and dry weight as well as cell wall components per unit volume significantly positively correlated with RPR. The internode water content (InW) significantly negatively correlated with RPR. Notably, these traits significantly correlated with RPR, and the QTLs of these traits co-localized with those of RPR. The corresponding results obtained from correlation analysis and QTL mapping suggested the presence of pleitropism or linkage between genes and indicated that these different approaches may be used for cross authentication of relationships between different traits.

Genetic architecture of rind penetrometer resistance in two maize recombinant inbred line populations

“…The broad-sense heritability of RPR in maize, estimated in two previous studies as well as our study, reached over 90% in some segregating populations [2,17]. The high broad-sense heritability reflects the accuracy and feasibility of the method used to quantify RPR in these studies.…”

“…Among these QTL, only the largest-effect QTL, qRPR3-1 , was also identified in two previous studies by Flint-Garcia et al [2] and Hu et al [17]; qRPR3-2 and qRPR6-2 were also detected in the Flint-Garcia et al study and were found to explain 6.7% and 13.8% of the phenotypic variation, respectively [2]. Our study revealed that a few large-effect QTL, together with some minor-effect QTL, provide most of the genetic basis of RPR, consistent with previous studies [2,17,18]. Together with this study, a total of 69 RPR-associated QTL have been identified in 33 segregating populations.…”

“…The majority of these QTL explained <15% of the phenotypic variation in RPR. An additional nine individual QTL and one more pair of epistatic interactions were detected in a recombinant inbred line (RIL) population crossed with a high-oil inbred line and B73, which account for another 1.15–12.43% of the phenotypic variation [17]. Recently, 18 QTL and 141 significant associations for RPR were identified using a nested association mapping panel containing 4,536 lines and 174 intermated B73 × Mo17 RILs.…”

“…Recently, 18 QTL and 141 significant associations for RPR were identified using a nested association mapping panel containing 4,536 lines and 174 intermated B73 × Mo17 RILs. Only 10 QTL were shared between two populations or two studies, reflecting the complex nature of stalk lodging [2,17,18]. …”

Spring barley stand structure as an indicator of lodging risk

“…Although the content of cellulose or lignin is related to stem rigidity (Taylor et al, 1999;Jones et al, 2001), the relationship between cellulose or lignin content and lodging resistance has not been clear. Stalk strength in previous work with maize significantly negatively correlates with lodging observed in the field (Hu et al, 2012). Application of abundant nitrogen at the ripening stage increases the accumulation of carbohydrates in stems and improves lodging resistance, but it also reduces cellulose content (Matsuzaki et al, 1972).…”