Aneuploid analyses of hybrid necrosis and hybrid chlorosis in tetraploid wheats using the D genome chromosome substitution lines of durum wheat

Abstract

Chromosomal locations of the Ne1 gene, one of the two complementary genes for type 1 hybrid necrosis, and two complementary genes, Cs1 and Cs2, for type 2 hybrid chlorosis in tetraploid wheats were determined by aneuploid analyses employing the D genome chromosome substitution lines of 'Langdon' durum wheat. The Ne1 gene of 'Langdon' is located on chromosome 5B, whereas the Cs1 gene of Triticum dicoccum 'Hokudai' and the Cs2 gene of T. timopheevi are located on chromosomes 5A and 4G, respectively. Chromosomes 4B and 4G show almost complete functional compensation, though they rarely pair with each other, but chromosome 4D of T. aestivum 'Chinese Spring' has only half the ability of chromosome 4G in compensating for chromosome 4B on the fertilization ability of the male gamete. The results have demonstrated the usefulness of the D genome chromosome substitution lines of durum wheat for determining the chromosomes carrying major genes in tetraploid wheat. The results of these studies support the reallocation of chromosome 4A to the B genome.Key words: durum wheat, hybrid necrosis, hybrid chlorosis, aneuploid analyses, chromosome substitution lines.