Quantitative Trait Loci Mapping of Maize Yield and Its Components Under Different Water Treatments at Flowering Time

Abstract

Drought or water stress is a serious agronomic problem resulting in maize (Zea mays L.) yield loss throughout the world. Breeding hybrids with drought tolerance is one important approach for solving this problem. However, lower efficiency and a longer period of breeding hybrids are disadvantages of traditional breeding programs. It is generally recognized that applying molecular marker techniques to traditional breeding programs could improve the efficiency of the breeding of drought-tolerant maize. To provide useful information for use in studies of maize drought tolerance, the mapping and tagging of quantitative trait loci (QTL) for yield and its components were performed in the present study on the basis of the principle of a mixed linear model. Two hundred and twenty-one recombinant inbred lines (RIL) of Yuyu 22 were grown under both well-watered and water-stressed conditions. In the former treatment group, plants were well irrigated, whereas those in the latter treatment group were stressed at flowering time. Ten plants of each genotype were grown in a row that was 3.00 m × 0.67 m (length × width). The results show that a few of the QTL were the same (one additive QTL for ear length, two additive QTL and one pair of epistatic QTL for kernel number per row, one additive QTL for kernel weight per plant), whereas most of other QTL were different between the two different water treatment groups. It may be that genetic expression differs under the two different water conditions. Furthermore, differences in the additive and epistatic QTL among the traits under water-stressed conditions indicate that genetic expression also differs from trait to trait. Major and minor QTL were detected for the traits, except for kernel number per row, under water-stressed conditions. Thus, the genetic mechanism of drought tolerance in maize is complex because the additive and epistatic QTL exist at the same time and the major and minor QTL all contribute to phenotype under water-stressed conditions. In particular, epidemic QTL under water-stressed conditions suggest that it is important to investigate the drought tolerance of maize from a genetic viewpoint.

The ZmASR1 Protein Influences Branched-Chain Amino Acid Biosynthesis and Maintains Kernel Yield in Maize under Water-Limited Conditions

“…These results were unexpected based on our previous PQL study, which did not reveal any QTL for maize yield and its component in the vicinity of the ZmASR1 chromosomal region (de Vienne et al, 1999;Jeanneau et al, 2002). Nevertheless, it may be pointed out that recently identified QTLs for ear length under waterstressed conditions (Lu et al, 2006) and female flowering time (Marino et al, 2009) are centered on the ZmASR1 locus. The finding that ZmASR1-OE plants demonstrated significant improvements in ear leaf area and shoot biomass yield, as well as increases in leaf dry weight and total chlorophyll content, implies that these improvements in vegetative productivity translated into improvements in reproductive performance and kernel yield.…”

Identification of a major quantitative trait locus for ear size induced by space flight in sweet corn

“…Many studies have identified QTL for traits relating to increased ear size in maize (Berke and Rocheford, 1995;Veldboom and Lee, 1996;Austin and Lee, 1996;Graham et al, 1997;Ajmone-Marsan et al, 2001;Lima et al, 2006;Yan et al, 2006;Sabadin et al, 2008;Lu et al, 2006Lu et al, , 2011. A total of 45 ED, 36 CD, 25 KD, and 27 KRN QTL were retrieved, but no QTL for ear size traits was found at bin 9.03 of chromosome 9 by conducting a QTL search for these traits in the Maize Genetics and Genomics Database (www.maizegdb.org).…”

“…Many studies have focused on the genetic characteristics and molecular mechanisms that affect yield, and many quantitative trait loci (QTL) for yieldrelated traits have been identified (Berke and Rocheford, 1995;Austin and Lee, 1996;Graham et al, 1997;Ajmone-Marsan et al, 2001;Lima et al, 2006;Yan et al, 2006;Sabadin et al, 2008;Lu et al, 2006Lu et al, , 2011. Because most of these QTL are minor QTL, it is difficult to utilize them for pyramiding favorable alleles.…”

Detection of quantitative trait loci (qtl) associated with yield and yield component traits in sorghum [Sorghum bicolor (L.) Moench] sown early and late planting dates

“…QTL analysis has been used to detect genomic regions and QTL associated with grain yield and its component for some other crop species (Lu et al, 1997;Lu et al, 2006;Liu et al, 2008;Xue et al, 2010). In sorghum, QTL associated with yield and yield component traits have been reported recently (Shehzad & Okuno, 2015).…”