Inheritance of glaucousness in wheat

It was found that all genetic variants for glaucousness over the wholeplant involved genes on the chromosomes of group 2. Of three recessivenonglaucous lines which arose spontaneously in Chinese Spring background,all were found to be due to deletion or mutation of the gene for glaucousnesson chromosome 2B.Another recessively nonglaucous line which arose in the backcrossing ofthe inhibitor gene of C.W.S. 5075 into Chinese Spring background was foundto have undergone a large terminal deletion of the short arm of chromosome2B.Chromosome 2D in Chinese Spring was found to bear a weaker gene homoeologousto that on chromosome 2B. It was found that chromosomes 2A bears no geneaffecting glaucousness.Two dominant ethyl methanesulfonate induced nonglaucous mutants were identifiedas alleles of the inhibitor gene on chromosome 2B.The variety Mentana was found to have no fully effective group-2 genes forglaucousness. The recessive gene for nonglaucousness on chromosome 2B ofMentana was mapped as lying between 33 and 50 map units from the centromere.A linkage stu~ gave no recombinants between the Mentana gene and theinhibitor gene from 5075, giving a maximum distance of 8 map units betweenthem. There is a strong case for thinking that both genes are alleles ofthe Chinese Spring gene for glaucousness.Genes capable of interacting to modi~ the dominance relationship of the2D inhibitor were found in the ABD XIII background Poso. It was found thatan extra dose of chromosome 2B could interact with the genes of ABD XIIIto give the same effect as the Poso genotype. Modifier genes in the backgroundsof Poso and 5075 also interacted to alter the dominance of the 2Binhibitor.Group 3 chromosomes were found to bear genes specifically for glaucousnessof the peduncle. Chromosome 3A bears the most effective gene, chromosome3B a less effective one and chromosome 3D apparently bears a null allele.Both Poso and Mentana were found to have genes which could substitute forthe chromosome 3A gene of Chinese Spring