Gametocidal chromosomes and their induction of chromosome mutations in wheat

Abstract

Certain alien chromosomes have been found to be preferentially transmitted in wheat. They are derived from differnt species of Aegilops, a genus related to wheat (Triticum). Such chromosomes ensure their own selective retention in wheat by causing sterility in gametes not carrying them, hence they are termed gametocidal chromosomes. There are at least three types of the gametocidal chromosomes that have different mode of gametocidal action and homoeology. The gametocidal chromosomes in the same homoeologous group (group 2, 3, or 4) have the same gametocidal action. Some of the gametocidal chromosomes induce chromosome mutations in either gametophytes or zygotes of common wheat with specific genotypes. The chromosome mutations preferentially occur in gametophytes without the gametocidal chromosome or in the zygotes when the gametocidal chromosome is delivered by the pollen. Chromosome mapping using induced deletions is under way.