| Stem rust resistance in accessions of Triticum timopheevi
and three Triticum aestivum lines with resistance from timopheevi
R.N. SAWHNEY and L.B. GOEL Division of Genetics, Indian Agricultural Research Institute, New Delhi-110012, India Triticum timopheevi (ZHUK.) ZHUK., a tatraploid wheat (2n=28) has been known as a vital and diverse soruce of resistance to a number of common bread wheat pathogens. The tetraploid wheats are also believed to carry a more valuable resistance to rusts (WATSON & LUIG, 1968). However, there are limited successful attempts in transferring disease resistance from T. timopheevi to bread wheat. Studies on accessions of T. timopheevi and T. aestivum stocks having genes derived from T. timopheevi indicate the presence of more than three distinct designated genes for low reaction to Puccinia graminis tritici, when tested with three North American cultures at the University of Missouri (U.S.A.) and four Australian cultures at the University of Sydney (MCINTOSH and GYARFAS, 1971). An assessment of a number of timopheevi accessions for genetic diversity in resistance to Indian stem rust strains is presented in this communication. Fifteen accessions of T. timopheevi and three T. aestivum stocks with genes for resistance, derived from T. timopheevi supplied by Dr. R.A. MCINTOSH, University of Sydney, Australia, and being maintained at the Division of Genetics, Indian Agricultural Research Institute, New Delhi, were tested in the seedling stage with 14 strains of stem rust pathogen (Puccinia graminis tritici (pers.) ERIKS and HENN.) viz., 17, 21, 21A-1, 24, 34, 40, 42, 117, 117-A, 122, 184, 194, 222 and 295. The infection types produced on these lines were recorded following (STAKMAN & LEVINE, 1922). The data obtained are presented in Table 1. The important conclusions drawn were : 1. CI 11651 (SrTt1& SrTt2) was observed resistant to all the Indian strains of stem rust. The resistance of CI 11651 to race 40 to which both SrTt1 and SrTr2 were found susceptible indicates the possibility of some additional factor in CI 11651. This observation is supported by MCINTOSH & GYARFAS (1971) who have also reproted some additional factor in this line when tested with a few selected North American and Australian cultures of stem rust. 2. The pattern of infection produced on PI 119442. PI 288033 and PI 326318 was identical suggesting the probable presence of same gene(s) for resistance to Indian stem rust strains although the source of these lines is different. 3. A number of T. timopheevi lines (PI 119442, PI 221421, PI 272523, PI 272530, PI 286073, PI 288038, PI 297030, PI 306557, PI 326318 and CI 11651) were resistant to race 21 that happens to be most prevalent race in the major wheat growing areas in India. The exploitation of these sources could be useful both in protecting the crop from the most prevalent race and in transference to diversity for resistance to stem rust. |
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