The 4e-Ms System Of Producing Hybrid Wheat

A cytogenetic method for producing hybrid seed using a nuclear gene for male sterility and an alien chromosome to obtain a pollination control system has been proposed in bread wheat (Triticum aestivum L.). Our objective was to transfer the alien chromosome 4E to the monogenic recessive male-sterile mutant Lanzhou (LZ), and then to establish an efficient cytogenetic system of maintaining the male sterility of the LZ mutant. After crossing the 4E disomic addition line 81529 (2n = 44) as male to LZ [2n = 42(msms) = 421, we obtained the 4E monosomic addition line [2n = 43(msms)] in the F-3 generation that had light-blue seed color. The line was homozygous for the malesterile gene (msms) of the host wheat and also had good self-fertility. The self-fertilized seeds segregated into 64.3% white (nonblue) with genotype 2n = 42(msms), 32.1% light blue with genotype 2n = 43(msms) and 3.6% deep blue with genotype 2n = 44(msms) grains. All plants grown from the white grains were completely male sterile. All plants grown from the light-blue grains had good self-fertility whose progeny seeds segregated into white, light-blue, and deep-blue grains again in succeeding generations. All plants grown from the deep-blue grains were self-fertile and retained their deep-blue color in the succeeding generations. When white grain male-sterile lines were crossed using any cultivar as the male parent, the hybrid plants had male fertility restored. And, this is the basis for the 4E-ms system of producing hybrid wheat.