Wx-1基因变异和优质HMW-GS组合对中筋小麦品质的影响

高分子量谷蛋白亚基(HMW-GS)和Wx蛋白是两个影响小麦理化品质和制成品品质的重要因素。为研究HMW-GS和Wx基因变异对小麦理化品质、面条感官评分和质构特性的影响,以镇麦9号和扬糯麦1号为亲本的2个高代系为试验材料,研究了优质HMW-GS 5+10及Wx基因缺失对小麦理化品质及面条加工品质的效应。结果表明,品系1与品系2的湿面筋含量和SDS沉淀值与镇麦9号相近,但显著好于扬糯麦1号。相较于镇麦9号,品系1与品系2的直链淀粉含量分别降低了1.5%和2.5%,其峰值黏度和稀懈值均显著高于镇麦9号,膨胀势也高于镇麦9号。5+10亚基显著提高了面条质构参数中的硬度和咀嚼性,而Wx基因缺失显著提高了面条的软硬度评分和光滑性评分。综合来看,具有5+10亚基和 Wx-D1缺失型的品系2具有较高的SDS沉淀值、面团形成时间和稳定时间、较低的直链淀粉含量、较高的峰值黏度、稀懈值和膨胀势,蛋白质和淀粉综合品质表现较好。品系2面条总评分最高,显著高于镇麦9号和扬糯麦1号,其主要体现在适中的面条软硬度和较好的光滑性。推测Wx基因缺失和优质HMW-GS聚合可显著提高小麦淀粉品质和蛋白质品质,有效改善面条的蒸煮品质和感官评分。

Effects of Wx-1 Allelic Variations and HMW-GS on Quality Improvement of Medium-Gluten Wheat

High-molecular-weight glutenin subunits(HMW-GS) and waxy proteins(Wx proteins) are major contributors to wheat flour quality and end-use quality. To evaluate the effect of HMW-GS and Wx proteins on physicochemical quality of medium-gluten wheat and properties of cooked Chinese white salted noodles and screen desirable lines for making high quality noodles, this study focused on two homozygous wheat lines derived from a bread wheat cv. Zhengmai 9(1/7+9/5+10, AABBDD) and a waxy wheat cv. Yangnuomai 1(1/7+9/2+12, aabbdd), and the effect of 5+10 subunits and Wx gene deficiencies on protein properties, starch characteristics and noodle quality were clarified. The results indicated that the protein quality of line 1 and line 2 was similar to that of Zhengmai 9, and better than that of Yangnuomai 1. Amylose content in line 1 and line 2 reduced 1.5% and 2.5%,respectively,comparing to that in Zhengmai 9. Line 1 and line 2 with Wx-A1 and Wx-D1 deficiency, respectively, especially the latter, exhibited higher peak viscosity, breakdown and swelling power of flour than Zhengmai 9. The results indicated that 5+10 subunits could significantly increase hardness and chewiness of TPA parameters, while single Wx gene deficiency significantly improved firmness score and smoothness score of cooked noodles. In general, line 2 with 5+10 subunits and Wx-D1 gene deficiency had strong gluten quality, better starch properties and higher sensory score. Consequently, it is an effective way to improve protein and starch quality of medium-gluten wheat by making use of the variation of Wx gene and HMW-GS.