AN UNUSUAL TRANSMISSION RATE OF THE DEFICIENT MALE GAMETE IN A SUBSTITUTION MONOSOMIC OF CHROMOSOME 3D IN WHEAT

Abstract

An unusual segregation of disomics, monosomics, and nullisomies (11, 38, and 51%, respectively, in summer and 11, 50, and 39%, respectively, in fall) was observed in the offspring of a substitution monosomic of chromosome 3D from Red Bobs into a hybrid of Rescue (Triticum aestivum L. emend Thell.) and Golden Ball (T. durum Desf.).Pollen with 20 and 21 chromosomes occurred in the frequency of 64 and 36%, respectively.The deficient male gametes effected fertilization in a frequency of 61%, that is, about the same frequency in which they occur, with two female parents, and in a frequency of 31% with two others, thereby showing the effect of stylar parent on the transmission of male gametes. The deficient female gametes are transmitted in a frequency of 76%. The 61% transmission of the deficiency on the male side and 76% on the female explain the unusual segregation in the summer crop.Monosomic plants selfed in the summer produced more nullisomics and fewer monosomics in their progeny than monosomics selfed in fall. The lower rate of functioning of the deficient male gamete in fall (about 51%) has been assumed to cause this difference.