SOME ASPECTS OF MONOSOMIC WHEAT BREEDING

Meiotic chromosome behavior was described for a group of monosomic plants, including representatives of the F1 and the first to seventh backcross generations. All plants were partially asynaptic. Rings-of-four were commonly seen in F1. and early backcross generations. Irregularities occurring among the progenies of monosomics were also described. These included monosomic plants which, through a process termed univalent-shift, were deficient for chromosomes other than those deficient in their respective monosomic parents. It was concluded that the irregular karyotypes occur as a consequence of partial asynapsis in the parent monosomics.