QTL Mapping For Agronomic Traits In Wheat

Many significant agronomic traits of wheat are quantitative traits. These traits are controlled by multiple genes and influenced by environment condition. The chromosomal loci of these genes are quantitative trait loci (QTLs). In this study, 153 families of DH population direved from wheat cross combination'Jinghua 1 / Xiaobaidong mai'were used as mapping population. SSR,EST-SSR and AFLP-SCAR primers were employed as molecular markers. Agronomic data of plant height, spike length, number of spikelets per spike, fertile spikelets per spike, one-thousand-grain weight, grain number per spike, grain hardness,awn characters were collected. Genetic analysis was conducted using composite interval mapping by WinQTLCart software. The main results were as follows:1. To analyze polymorphisms of Jinghua 1 and Xiaobaidongmai, totally 1602 pairs of SSR primers,EST-SSR primers and AFLP-SCAR primers were employed as molecular markers. 370 pairs of polymorphous markers were obtained, Polymorphism ratio of three kinds of molecular markers were 25.9%,13.8%,22.2%.2. 339 of 370 polymorphic primers amplified clear and stable DNA bands of 367 loci in DH. The data of 367 loci of 153 DH lines were analyzed by genetic software QGAstation1.0. A genetic linkage map of 4478.4 cM was constructed. Total 277 loci were distributed in 34 linkage groups of 21 chromosomes of wheat. The average distance between markers was 16.1 cM. 8 SSR markers, 17 EST-SSR markers and 14 AFLP-SCAR markers were located in this map.3. The data of plant height, spike length, number of spikelets per spike, fertile spikelets per spike, one-thousand-grain weight, grain number per spike, grain hardness, awn characters of'Jinghua 1/ Xiaobaidongmai'DH lines were collected. Normal distribution of 8 agronomic traits were determined. The results showed that this population can be considered to be an ideal material for further constructing genetic map and QTLmapping.4. 9 QTLs of number of spikelets per spike were located on 1B,2D,4A,5A,5B,7B by composite interval mapping analysis of WinQTLCart software. The major QTLs were located on chromosome 1B,2D,4A and 7B, the interval markers were between Xwmc367-Barc80, Xgwm259-Xwmc367, Xgwm382-Xgdm87, Barc78- Xgwm160, Xwmc500-Cfa2040, accounting 18.97%,18.99%,22.14%,23.37%,26.94% of the phenotypic variance. These works will do great help to fine mapping for QTL, map-based cloning of these genes, and maker-assisted selection.