Submitted to: Journal of Heredity
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 14, 2000
Publication Date: January 15, 2001
Citation: Dogramaci-Altunte, M., Peterson, T.S., Jauhar, P.P. 2001. Anther culture-derived regenerants of durum wheat and their cytological characterization. Journal of Heredity 92:56-64. Interpretive Summary: Anther culture is proving increasingly useful in wheat improvement both as a source of haploids (plants with half the chromosome number) as well as new genetic variation. We studied the anther-culture ability of ten durum wheat cultivars, using three different growth conditions, and four different culture media. From a total of 86400 anthers cultured from the 10 cultivars, we obtained 324 plants, 248 green and 76 albino (without the green pigment). Green plant regeneration was influenced significantly by genotype (the cultivar) and its growth condition, as well as by genotype growth condition interactions. The regenerants showed genetic variation (gametoclonal/somaclonal variation) and we identified the factors contributing to this variation. Numerical and structural alterations of chromosomes (rod-like structures that carry the genes for various traits) were the main factors in generating gametoclonal/somaclonal variation, which in some cases may be exploited in wheat breeding. Durum wheat has two genomes (sets of chromosomes), A and B, contributed by its two progenitors. We found that there was a preferential multiplication of the B-genome chromosomes. We made several other interesting observations, which are of basic interest in research as well as in applied plant breeding.
Technical Abstract: Anther culture is being increasingly used in cereal crop improvement both as source of haploids and new genetic variation. We studied the androgenetic ability of ten cultivars of durum wheat, using three different growth conditions, and four media. From a total of 86,400 anthers cultured, 324 plants were obtained, 248 green and 76 albino. Genotypes, growth conditions, and media significantly affected anther response and callus production; interactions were also significant. Green plant regeneration was influenced significantly by genotype and growth condition, as well as by genotype growth condition interactions. Albino plant regeneration was affected significantly only by growth condition. Regenerants showed gametoclonal/somaclonal variation. Chromosome numbers of the regenerants ranged from 14 to 70. All 76 haploid plantlets (2n=2x=14; AB) were albinos. Chromosome number in the green plantlets ranged from 28 to 70. Chromosome number also varied in regenerants originating from the same callus. Both intergenomic and intragenomic multivalents were observed. An interesting feature was the preferential multiplication of B-genome chromosomes, which formed multivalents. We observed several chromosomal abnormalities, which seemed to increase with the level of polyploidy. Translocations, dicentric chromosomes, chromatid exchanges, and Robertsonian translocations involving the A- and B-genome chromosomes were observed. Centric and acentric fragments, and telocentrics were observed. Chromosome multiplication and structural aberrations induced during culture may constitute the bases of gametoclonal and somaclonal variations.