小麦粒重基因TaCwi-A1功能标记CWI22、CWI21的验证及应用

Validation and Application of Function Markers CWI22 and CWI21 of TaCwi-A1 Gene Related to Wheat Kernel Weight

【目的】验证已开发的TaCwi-A1功能标记CWI22、CWI21检测小麦千粒重的可靠性,为分子标记辅助选择提供参考信息。同时用该标记检测新疆小麦品种资源,探讨TaCwi-A1等位变异类型及分布频率。【方法】首先以110份新疆冬小麦品种资源为材料,用CWI22、CWI21检测TaCwi-A1基因型,并利用SKCS测定千粒重,比较TaCwi-A1a、TaCwi-A1b基因型品种间千粒重的差异。再以1 241份新疆小麦品种资源为材料,对TaCwi-A1基因型进行分子标记检测。【结果】在110份新疆冬小麦品种资源中,有46份材料能够用CWI22扩增出402 bp的目的片段,说明含有TaCwi-A1a;有64份材料能够用CWI21扩增出404 bp的目的片段,说明含有TaCwi-A1b;并且TaCwi-A1a基因型品种(系)的千粒重(43.5 g)显著高于TaCwi-A1b(40.9 g)(P<0.05)。1 241份新疆小麦品种资源中,TaCwi-A1a的分布频率为62.6%,TaCwi-A1b为37.4%。其中,冬小麦中TaCwi-A1a的分布频率为63.0%,TaCwi-A1b为37.0%;春小麦中TaCwi-A1a的分布频率为61.7%,TaCwi-A1b为38.3%,并且TaCwi-A1a在不同类型冬、春小麦品种资源中的分布频率大小顺序均为国外品种(系)>国内品种(系)>自育品系>审定品种>地方品种;新疆小麦审定品种中,冬小麦TaCwi-A1a的分布频率为40.0%,TaCwi-A1b为60.0%,春小麦TaCwi-A1a的分布频率为68.6%,TaCwi-A1b为31.4%。在1990年以前、1991—2000年、2001年以后3个阶段的审定品种中,TaCwi-A1a和TaCwi-A1b的分布频率分别为11.1%和88.9%、50.0%和50.0%、69.2%和30.8%。【结论】TaCwi-A1的分子标记CWI22、CWI21能够较好地区分小麦千粒重的大小,可用于粒重的分子标记辅助选择。在新疆小麦品种资源中,TaCwi-A1a有较高的分布频率。其中,冬小麦品种资源中的分布频率略高于春小麦品种资源,引进品种(系)高于自育品种(系),自育品种(系)高于地方品种。在地方品种和自育品种(系)中,TaCwi-A1a在春小麦中的分布频率明显高于冬小麦,说明新疆冬、春小麦育种对粒重的选择存在一定的差异;但总体都有较强的选择压力,使TaCwi-A1a在审定品种中的分布频率逐渐提高。

[Objective] In order to provide some information for molecular marker assisted selection, the function markers CWI22 and CWI21 of TaCwi-A1 gene related to wheat kemel weight were validated. The allelic frequencies at TaCwi-A1 locus were detected by those markers in Xinjiang wheat germplasm. [Method] The 110 Xinjiang winter wheat varieties were genotyped with CWI22 and CWI21, and the difference in thousand kernel weight （TKW） among varieties with TaCwi-Ala and TaCwi-Alb were analyzed. The allelic variations at TaCwi-A1 locus were detected by CWI22 and CWI21 in a total of 1 241 Xinjiang wheat germplasms. [Result] In the 110 Xinjiang winter wheat varieties, a 402-bp fragment could be amplified by CWI22 in 46 varieties, which means they had genotype of TaCwi-Ala, a 404-bp fragment could be amplified by CWI21 in 64 varieties, which means they had genotype of TaCwi-Alb. And the TKW of varieties with TaCwi-Ala （43.5 g） was significantly higher than that with TaCwi-Alb （40.9 g） （P〈0.05）. In the 1 241 Xinjiang wheat germplasms, the frequencies of TaCwi-Ala and TaCwi-Alb were 62.6% and 37.4% in all germplasms, 63.0% and 37.0% in winter wheats varieties, 61.7% and 38.3% in spring wheat varieties, respectively. In different types of varieties of both winter and spring wheat germplasm, the frequency of TaCwi-A l a was in order of exotic varieties （lines）〉 domestic varieties （lines）〉breeding varieties （lines）〉released varieties〉landraces. In Xinjiang released varieties, the frequencies of TaCwi-Ala and TaCwi-Alb were 40.0% and 60.0% in winter wheats, 68.6% and 31.4% in spring wheats, respectively. In three stages of before 1990, 1991 to 2000, and after 2001, the frequencies of TaCwi-Ala and TaCwi-Alb were 11.1% and 88.9%, 50.0% and 50.0%, 69.2% and 30.8%, respectively. [Conclusion] The markers CWI22 and CWI21 of TaCwi-A1 gene can efficiently distinguish the differences of wheat TKW, which can be used for marker assisted selection of kernel weight （KW）. In Xinjiang wheat germplasm, TaCwi-Ala gene has a high frequency. And the frequency of TaCwi-Ala gene in winter wheat germplasm is a little higher than spring wheat germplasm, introduced varieties （lines） is higher than breeding varieties （lines）, breeding varieties （lines） is higher than landraces. In both landraces and breeding varieties （lines）, the frequencies of TaCwi-Ala gene in spring wheat varieties are higher than winter wheat varieties, which means that the breeding selection of KW in winter and spring wheat are different in Xinjiang, but there had high selection pressure in all, which makes the frequency of TaCwi-Ala gene in released varieties increase.