| Development of monosomic lines in durum wheat*
R.R. HANCHINAL and J.V. GOUND University of Agricultural sciences Dharwad Campus-580005, Karnatak state, India The cultivated species of wheat, Triticum durum (n=14:AABB) and T. aestivum (n=21:AABBDD) behave meiotically as true allopolyploids, with regular bivalent formation inspite of intergenomic pairing ability that exists between homeologous chromosomes. This meiotic behaviour which confers the tetraploid and hexaploid wheats a great cytological stability and high fertility is controlled by one or more genes which inhibit pairing of homeology chromosomes (OKAMOTO 1957; RILEY 1958; 1960; RILEY & CHAPMAN 1958). Genetic analysis in polyploid wheats have been difficult due to duplication or triplication of genes and aneuploidy (SEARS 1954) has become one of the best tools in genetic and cytogenetic analysis of polyploid wheats. Attempts to obtain monosomics in tetraploid wheats have not been successful since such individuals are very weak and sterile having a low transmission ability of the monsomic condition (MOCHIZUKI 1968 a, b). The present investigation deals with the possibilities of isolating monosomic lines in durum wheat cv Bijaga Yellow by chromosome conversent method. Material and Methods To obtain monosomic lines in T. durum cv 'Bijaga Yellow', the first fourteen monosomic lines of Pb C 591 (Monosomic for A- or B-genomes) were crossed to Bijaga Yellow. In F1 generation, the majority of the populations were of two types i.e. plants with 34 chromosomes (13"+8') which are monopentaploids and the second type being the plants with 35 chromosomes (14"+7') which are eupentaploids. In F1 generation the plants with 34 chromosomes were selected and back crossed to Bijaga Yellow. In first back cross generation, plants with 13"+2' were selected and were again back crossed to Bijaga Yellow to get monosomic plants of the donor parent. In second back cross generation the plants with only 13"+1, were selected and back crossed to Bijaga Yellow to raise BC3 generation. During the course of back crossing the chromosomes of the D-genome were eliminated. |
| * Part of the Ph. D. thesis submitted by the senior author to the University of Agricultural Sciences, Bangalore, India. |
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