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United States Department of Agriculture

Agricultural Research Service

Title: Effects of Homoeologous Group-5 Chromosomes on the Ability of Durum Wheat and Bread Wheat to Produce Haploids

Authors
item Jauhar, Prem
item Rahman, Hamidur - BANGLADESH AG UNIV
item Rao, Marepalli - UNIV OF CINCINNATI

Submitted to: Journal of Crop Improvement
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 30, 2006
Publication Date: January 10, 2008
Citation: Jauhar, P.P., Rahman, H., Rao, M.B. 2008. Effects of homoeologous group-5 chromosomes on the ability of durum wheat and bread wheat to produce haploids. Journal of Crop Improvement. 21:1-11.

Interpretive Summary: Haploid plants with half the chromosome number are very useful in basic and applied research because they provide an easy method to produce pure, homozygous breeding lines. Efficient methods of producing haploids must, therefore, be found. Apart from improving hybridization procedures and embryo-culture techniques, cytogenetic means of enhancing haploid production should be explored. We showed earlier that substitution of bread wheat chromosome 5D for 5B confers on durum wheat greater ability to produce haploids via hybridization with maize. In this study, we have investigated the effects of other chromosomes (belonging to the same homoeologous group-5) on induction of haploidy in both durum wheat and bread wheat. Appropriate stocks, in which some chromosomes were deleted but replaced by related chromosomes in the same group, were obtained. All these materials were crossed with maize, using the techniques standardized earlier. The durum disomic substitution 5D(5B) line, in which bread wheat chromosome 5D was substituted for durum chromosome 5B, gave a higher yield of haploids compared to 5D(5A). Among the bread wheat stocks, the stock N5B-T5D (in which chromosome 5B was altogether missing, but chromosome 5D was present in 4 doses instead of the normal double dose) proved to be the best producer of haploids. Further research on these lines may unravel the haploidy-inducing genetic mechanism(s) helping to accelerate the production of haploids.

Technical Abstract: An efficient method of producing haploids is important so that they can be employed in basic and applied research. Apart from improved culture methods, cytogenetic means of enhancing haploid production should be explored. We showed earlier that substitution of bread wheat chromosome 5D for 5B confers on durum wheat greater ability to produce haploids via hybridization with maize. In this study, we investigated the effects of homoeologous group-5 chromosomes on induction of haploidy in both durum wheat (using disomic substitution lines, 5D(5A) and 5D(5B), and bread wheat (using 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. The durum disomic substitution 5D(5B) gave a higher yield of haploids compared to 5D(5A). Among the nulli-tetras, N5B-T5D and N5B-T5A were the best producers of haploid plantlets, but N5B-T5D was better of these two ('2 = 5.4297; p = 0.0198). Clearly, tetrasomy for chromosome 5D combined with nullisomy for 5B facilitates the production of haploids in Chinese Spring wheat. Further research along these lines may unravel the haploidy-inducing genetic mechanism(s) helping to accelerate the production of haploids.

Last Modified: 7/31/2014
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