Homoeologous Group-5 Chromosome Effects on the Ability of Durum and Bread Wheats to Produce Haploids

Abstract

Haploid plants have proved to be useful tools in basic cytogenetic studies. Maize-mediated chromosome elimination provides the method of choice for haploid production in disomic polyploids like wheat (Triticum aestivum L.). Different chromosomes may have varying effects on haploid production. Previously, we studied the effect of the substitution of bread wheat chromosome 5D for 5B on durum wheat's ability to produce haploids via hybridization with maize (Zea mays L.). In the present study, we have investigated the effects of all homoeologous group-5 chromosomes on induction of haploidy in both durum wheat [using the cultivar Langdon and its disomic substitution lines, 5D(5A) and 5D(5B)], and bread wheat (using the cultivar Chinese Spring and its nullisomic-tetrasomic lines, N5A-T5D, N5D-T5A, N5A-T5B, N5B-T5A, N5B-T5D, and N5D-T5B). All these materials were crossed with maize, using the techniques standardized earlier. Although the overall production of haploids was low, the durum disomic substitution 5D(5B) gave a higher yield of haploid plantlets compared with 5D(5A). Among the nullitetras, N5B-T5D and N5B-T5A were the best producers of haploid plantlets, but N5B-T5D was better of these two (χ2 = 5.4297; p = 0.0198). Thus, among these cytogenetic stocks, tetrasomy for chromosome 5D combined with nullisomy for 5B seemed to increase the production of haploids. It would appear that chromosome 5D of bread wheat has genes for haploidy induction and further research along these lines may unravel any such haploidy-inducing genetic mechanism(s).