| 1) Use of qualitative scale for monitoring rust resistant/susceptible
genotypes. 2) Small population size. This warrants for testing the F3 progeny for rust resistance. The digenic ratios viz 11:5, 13:3, 9:7, 15:1 suggested threshold effect, epistasis, complementary or duplicate gene action respectively. So, for breeding for resistance to rusts, such types of interactions must be kept in view. According to avirulence/virulence formulae, the comperative study involving three cultures suggested the tentative presence of genes Lr2, Lr3, Lr10, Lr12, Lr14, Lr15, Lr17, Lr18, Lr21, Lr23, LrB, LrEG and Lr20 in parent WC 313 and Fortylaya. Precise nature of genes involved in rust resistance can be worked out by crossing the parents possessing different sets of resistance genes. Such an information will enable a wheat breeder to evolve varieties with multigenic or monogenic back ground stable for their reaction against wheat rust. References GUPTA, A.K & R.G. SAINI 1981. Some genotypes of Puccinia recondita isolated from Indian leaf rust races. Cereal Rust Bull. 9: 46-48. JOSHI, L.M. 1978. Diseases. Wheat Research in India 1966-1967. Edt, P.L. Jaiswal, S.N. Tata and R.S. Gupta. I.C.A.R. Publication. pp. 126-151. STAKMAN, E.C., D.M. STEWART & W.Q. LOEGERING 1962. Identification of physiologic races of Puccinia graminis var. tritici. USDA-ARSE 617 Revised 53p. VAN DER PLANK, J.E. 1968. Disease resistance in plants. Academic Press, New York, London. |
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