应用分子标记辅助选择甜糯双隐基因型玉米种质

Use of molecular marker-assisted selection(MAS)in corn breeding with double recessive sweet-waxy gene

为解决传统育种技术选育甜糯玉米自交系过程长、效率低的问题,以超甜玉米与糯玉米杂交组合的甜质S1家系为材料,利用与糯玉米隐性基因(w)x紧密连锁的3对SSR标记phio22、phio27和phio61进行辅助选择选育。结果表明,引物phio22的PCR扩增效果较好,在玉米苗期成功鉴定出含有双隐性纯合wxwxsh2sh2基因型的甜糯玉米单株9株,含WxWx显性纯合基因个体9个和含Wxwx杂合基因个体22个,从而在甜质S1家系早代实现了隐性纯合wxwx基因的分子标记辅助选择。对甜糯双隐基因型植株连续自交4代,获得一批优良甜糯双隐玉米自交系:糯集02A79×金银甜、柳糯5号×华珍-1和金银甜×宜糯02A81-1。利用这些自交系与当地优良的糯玉米自交系进行组配,获得产量、株型、抗性、品质优良的3个组合:(糯集02A79×金银甜)×玉美头601-1、(柳糯5号×华珍-1)×玉美头601-1和(金银甜×宜糯02A81-1)×玉美头601-1。因此,利用分子标记辅助选择技术可明显提高甜糯玉米育种效率,加快甜糯玉米自交系的育种进程。

The present study was conducted to resolve the problem of long and less efficient breeding period encountered during breeding of waxy-sweet corn inbred lines by conventional breeding techniques. The wxsh2 genotype S1 generation derived from sweet （sh2sh2） corn and waxy corn combinations were used as materials and identified with three pairs of SSR marker primers, viz., phio22, phio27 and phio61, which are closely linked with waxy recessive gene （wx）. The results showed that the amplified effect of primer phio22 was better and could identify 9 corn plants with wxwxsh2sh2 genotype, 9 individuals with WxWx gene and 22 individuals with Wxwx gene at seedling stage of corn. Therefore, the recessive pure gene wxwx could be identified by molecular marker-assisted selection （MAS） at early generation of sweet S1 line. Several good waxy--sweet （wxsh2） corn inbred lines viz., Nuoji 02A79×Jinyintian, Liunuo 5×Huazhen-1 and Jinyintian×Yinuo 02A81-1 were derived from the double recessive genotype sweet-waxy plants after continuous inbred for four generations. When these corn inbred lines were combined with good local waxy corn inbred lines, three combinations with high yield and better plant type, resistance and quality, viz., （Nuoji 02A79×Jinyintian）×Yumeitou 601-1, （Liunuo 5×Huazhen-1）× Yumeitou 601-1 and （Jinyintian×Yinuo 02A81-1 ） ×Yumeitou 601-1 were developed. So, applying MAS could improve the breeding efficiency of sweet-waxy corn and accelerate the breeding process of sweet-waxy corn inbred line.