2. Gene for unreduced eggs.


A recessive gene has been found which produces haploid male gametophytes but on the female side gives chiefly egg cells with an unreduced number of chromosomes. Ears from the homozygous plants appear highly sterile with a few plump (diploid) seed scattered among the numerous shriveled (triploid) kernels. Classification of segre­gating families is easy and good ratios are obtained in backcross and F2 progenies. The limited studies of megasporogenesis which have been made indicate that the first meiotic division is normal; production of diploid eggs presumably arises at either the second meiotic divi­sion or during the development of the female gametophyte. Genetic studies, using linked genes in a heterozygous condition, of the con­stitution of the diploid eggs are underway. This gene promises to

be valuable for the study of crossing over.