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

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 02A81-1were 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.