| Study of allied species of Triticum against
Indian cultures of leaf rust races. L.B. GOEL and R.N. SAWHNEY Division of Genetics Indian Agricultural Research Institute New Delhi-110012, India Variability in genes for resistance is essential for the success of breeding resistant cultivars. The variation and parallel evolution in the wheat rust pathogen, in particular, demand continued effort in search of new resistances and in this direction study of allied species for their effectiveness against the local virulences in the country offer rich dividends. The use of rust resistance from allied species of Triticum goes back to 1930, when McFadden developed Hope and H44 from the cross Yaroslov Emmer (T. turgidum dicoccum group) x Marquis. These varieties were responsible for the largest rust free situation (1938-49) in the United States. SHANDS (1941) could transfer successfully the stem rust, leaf rust and powdery mildew and other disease resistant properties of T. timopheevi to common wrheat. A number of T. timopheevi lines and a few T. aestivum lines having derived their resistance from T. timopheevi were studied for their resistance to Indian cultures of stem rust races (SAWHNEY and GOEL, 1980). In this communication, we report the resistance of a number of Triticum species of tetraploid group against Indian cultures of leaf rust (Puccinia recondita f. sp. tritici) races. Seven species of Triticum viz., T. compactum var. fitosodi, T. dicoccum var. rufum, T. carthlicum var. faligirresum, T. polonicum var. gorskyis, T. turgidum var. lusitanicum. T. timopheevi var. typicum and T. timopheevi var. viticulosum, maintained at the Indian Agricultural Research Institute, were tested against the Indian cultures of leaf rust races viz., 10, 11, 12, 17, 20, 63, 77, 77A, 104, 107, 108, 162 and 162A at the seedling stage in the green house at a temperature ranging 8C-22C. The results are presented in Table 1. The important conclusions drawn were: (1) T. timopheevi var. typicum and T. timopheevi var. viticulosum were found resistant to all the cultures of Indian leaf rust races used. Complete effectivness of both the varieties of T. timpoheevi against all the races, however, provides no information on the relationship of resistance in the two lines. (2) Variation for resistance in the three species, T. compactum var. fitosodi, T. dicoccum var. rufum and T. carthlicum var. fuligirresum to different race or group of races suggests that the leaf rust resistance in these three sources is different. (3) T. polonicum var. gorskyis and T. turgidum var. lusitanicum were observed completely ineffective against the races tested and thus have no value for breeding resistance to leaf rust. High degree of resistance in T. timopheevi lines to stem rust (SAWHNEY and GOEL,1980) and to leaf rust reported in the present study suggests that T. timopheevi lines could be an excellent source for imparting high degree of resistance against Indian races of stem and leaf rust pathogen. Resistance from other allied species at (2) above could be useful as diverse source of resistance against the race or group of races to which these were found effective. Literature Cited SAWHNEY, R.N. and GOEL, L.B. 1980. Stem rust resistance in accessions of Triticum timopheevi and three Triticum aestivum lines with resistance from timopheevi. Wheat Inf. Serv., 50: 46-48. SHANDS, R.G. 1941.Disease resistance of Triticum timopheevi transferred to common winter wheat. Agron. J., 36: 709-712. |