Evaluation Of Four Molecular Markers Associated With Pre-Harvest Sprouting Tolerance And Sreening PHS Tolerant Cultivars In Chinese Wheats

Pre-harvest sprouting (PHS) is the premature germination of wheat seeds so that the embryo starts growing while still on the head in the field. This occurs when wet conditions delay harvest. PHS has a high economic cost in reducing the grain yield and quality of the seed and end-products. Wheat production in Anhui Province covers two ecological regions, namely Yellow-Huai Facultative Winter Wheat Region (YHFWWR) and Middle-Lower Yangtze Valley Winter Wheat Region (MLYVWWR). PHS occurs frequently and severely in this area. In recent years, resulted from the food processing and commercial concerns, white wheat is in predominant. However, white varieties are more likely to exhibit PHS than red under similar environmental conditions. Accordingly, breeding PHS resistant white wheat cultivars is one of the most important objectives in wheat breeding.In this study, four markers associating with PHS resistance (Vp1B3, Xgwm155, Xgwm269 and Xbarc170) were adopted to screen 97 Chinese wheat landraces and main varieties (or lines) from YHFWWR and MLYVWWR. The objectives of the study were to assess the efficiency of using these markers to select high PHS resistance wheat genotypes. Results showed:1. The germination index (GI) of 77 white cultivars was 68.6% on average, ranging from 1.9% to 99.3%. The GI of 20 red cultivars was 35.6% on average, ranging from 10.4% to 92.8%.2. Maker Vp1B3 was used to test all 97 wheat cultivars (or lines) resulting in three polymorphic bands as Vp1Ba, Vp1Bb and Vp1Bc, respectively. Vp1Ba marker was associated with wild type (PHS sensitive) and Vp1Bb and Vp1Bc were associated with resistant mutant type. Nineteen genotypes (including 16 white cultivars and 3 red cultivars) showed Vp1Ba genotype (with 652 bp amplicant). Four cultivars showed Vp1Bb genotype (with 845 bp amplicant) and 74 cultivars (including 58 white cultivars and 16 red cultivars) showed Vp1Bc genotype (with 569 bp amplicant).3. Marker Xgwm155 gave four polymorphic bands among the tested wheat genotypes, with C-type band was associated with PHS resistance. Marker Xgwm269 gave two polymorphic bands, with A-type band was associated with PHS resistance. Marker Xbarc170 gave five polymorphic bands, with C-type band was associated with PHS resistance.4. Statistical analysis showed that the difference of GI value between Vp1Ba and Vp1Bc wheat genotypes was not significant. However, the difference of GI value between Vp1Ba/Vp1Bc and Vp1Bb genotypes was significant (F=7.277, P<0.0035). For each of the other three molecular markers, no significant difference was found in GI value among all wheat genotypes.