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颗粒结合型淀粉合成酶Ⅰ(GBSSI,Waxy蛋白)是小麦胚乳中直链淀粉合成的关键酶。小麦基因组中存在3个Waxy基因(Wx-A1、Wx-B1、Wx-D1)。在白火麦中Wx-D1位点的突变(Wx-D1b)引起Wx-D蛋白的缺失,导致直链淀粉含量下降,其面粉表现出部分糯性。与目前生产上推广品种相比,白火麦的农艺性状较差,产量非常低。为了培育农艺性状优良的部分糯性小麦,我们将白火麦与具有优良农艺性状的小麦品种PH85-16、济南17和烟农15(轮回亲本)分别进行杂交,后代分别与相应的三个轮回亲本回交五代,在每代中均选择农艺性状与轮回亲本相近并含有Wx-D1b的后代。在第六代自交后选择具有Wx-D1b的纯合体,选出的单株连续自交三代。获得了六个农艺性状与轮回亲本相似的品系,它们均携带纯合的Wx-D1b位点。研究表明采用回交的方法并结合基于Wx基因序列的分子标记技术,是培育优良部分糯性小麦的一种非常有效的方法。本研究培育出的部分糯性小麦品系可以直接用于大田生产。
Particle bound starch synthase Ⅰ (GBSSI, Waxy protein) is the key enzyme in amylose synthesis in wheat endosperm. Three Waxy genes (Wx-A1, Wx-B1, Wx-D1) exist in the wheat genome. Mutation (Wx-D1b) in the Wx-D1 locus in the white firewheel caused a loss of the Wx-D protein resulting in a decrease in the amylose content of which the flour showed partial waxiness. Compared with the current production of the promotion of varieties, white fire wheat agronomic traits worse, the yield is very low. In order to cultivate part of waxy wheat with good agronomic traits, we crossed the white wheat with wheat cultivars PH85-16, Jinan17 and Yannong15 (reincarnated parents) with excellent agronomic traits respectively. The offspring were crossed with the corresponding three recurrent parents Five generations were backcrossing, and offspring with agronomic traits similar to the recurrent parent and containing Wx-D1b were selected in each generation. In the sixth generation of self-selection with the Wx-D1b homozygotes, the selected plant selfing for three generations of continuous. Six lines with similar agronomic traits and recurrent parents were obtained, all of which carried homozygous Wx-D1b loci. Studies have shown that the use of backcrossing methods combined with molecular markers based on the Wx gene sequence is a very effective way to cultivate good part of waxy wheat. Some of the waxy wheat cultivars developed in this study can be directly used for field production.