Diversity for Resistance to Leaf Rust in Triticum aestivum. Shiwani , Department of Genetics, Punjab Agricultural University, Ludhiana, India 141004. R. G. Saini, Department of Genetics, Punjab Agricultural University, Ludhiana, India 141004. Plant Dis. 77:359-363. Accepted for publication 4 August 1992. Copyright 1993 The American Phytopathological Society. DOI: 10.1094/PD-77-0359.

Multipathotype tests were conducted on 37 selected Indian and international cultivars of wheat (Triticum aestivum) against leaf rust (Puccinia recondita f. sp. tritici) race 77 and its three pathotypes: 77A, 77-1, and 77-2. On the basis of infection types at seedling and adult-plant stages, these cultivars could be classified into 22 distinct groups. These groups seem to carry diverse, undescribed adult-plant resistance (APR) genes. Some of these APR genes exhibit race specificity and can be identified using appropriate races at different developmental stages. Gene Lr10 is postulated in 10 wheats. Cultivars Girija, HD2135, HD2270, HI977, HUW234, Hybrid 65, and UP262 appear to possess Lr23. A resistance gene similar to that in TcLr3ka is suggested to confer APR in CPAN1676. Cultivar Tobari 66 seems to have Lr34 and LrT3. Because a majority of cultivars were resistant to pathotype 77A and/or 77-1+77-2 in field tests, some may be potential sources of effective and diverse APR factors which, in combination with each other or with known Lr genes, may impart durable resistance to leaf rust.