MAPPING QUANTITATIVE TRAIT LOCI FOR GRAIN YIELD AND YIELD RELATED TRAITS IN A HEXAPLOID WINTER WHEAT DOUBLED HAPLOID POPULATION

Abstract

Improving wheat grain yield potential is imperative to match the increasing food demand associated with a fast growing population. Genetic and modeling approaches were employed to investigate the genetic basis and phenotype network regarding grain yield and yield related traits in a soft red winter wheat doubled haploid population. The population and two parents were evaluated in five year-location trials in the USA and genotyped by high throughput DNA markers including simple sequence repeat (SSR) and single nucleotide polymorphism (SNP). Bi-parental linkage mapping identified a number of QTLs for grain yield and yield related traits among which sixty were for grain yield components (GYLD, grain yield; SPSM, spikes per square meter; TGW, thousand grain weight; GPS, grains per spike; GWPS, grain weight per spike), seventy four were for plant architecture (PHT, plant height; FLL, flag leaf length; FLW, flag leaf width; FLA, flag leaf area; FLS, flag leaf shape or length/width ratio), and one hundred and nine were for spike morphology (SL, spike length; TSN, total spikelet number per spike; FSN, fertile spikelet number per spike; SSN, sterile spikelet number per spike; SC, spike compactness; GSP, grains per spikelet). In addition, structural equation modeling is described to construct a phenotype network. It revealed that GSP and FSN may mediate yield component compensation. Furthermore, doubled haploid lines DH96 and DH84 may have potential as new high-yielding cultivars for the Mid-Atlantic region.