QTL Analysis of End-Use Quality in a Mapping Population from Texas Wheat

Abstract

Wheat (Triticum aestivum L.) breeders strive to develop high-yielding varieties with outstanding end-use quality attributes and tolerance to biotic and abiotic stresses. Wheat end-use quality, particularly bread making, is influenced by both genetic and environmental factors. The objective of this study is to map and tag quantitative trait loci (QTL) linked to important end-use quality attributes. A population of 179 F5:7 recombinant lines (RIL) was derived from the cross ‘TAM 111’/TX05A001822. In 2017 and 2018, agronomical traits (heading date, plant height and grain yield) were measured in three different environments (Chillicothe, Dumas, McGregor) in TX. Additionally, quality traits including single kernel characteristics, such as kernel hardness and diameter; flour yield; protein content quantified Near Infra-red (NIR), and dough mixing properties, including midline peak time, midline peak height and width, were measured for Chillicothe environment in 2017 and Dumas and College Station environments in 2018. Genotyping-by-sequencing of 179 RILs and the two parents was conducted using Ion Torrent Proton sequencer and produced a set of 2,658 single nucleotide polymorphisms (SNPs). Through aligning the SNP flanking sequences with IWGSC RefSeq 1.0, the physical position of all SNPs was determined and they covered 20 chromosomes of wheat genome. A high-density genetic linkage map consisting of 35 linkage groups was constructed using JoinMap 4.0. Genetic regions associated with end-use quality traits were detected through inclusive composite interval mapping using QTL IciMapping 4.1. Sixteen QTL on the wheat chromosomes 1B, 1D, 4A, 5A, 5B, and 6D were identified, including seven consistent QTL that appeared in more than one environment or analyses and one pleiotropic QTL that affect four different traits. One major QTL for end-use quality traits related to dough quality was located on chromosome 1D at 411 Mb that is close to Glu-D1 and 419 Mb (at 77cM) whereas QTL for plant height showed a wide distribution along the chromosomes 4A, 5A, 5B, and 6D. In conclusion, identified those QTL in the current study could be useful and beneficial in marker assisted selection of the current germplasm for end-use quality trait improvement in a wheat breeding program.