| Results and Discussion Slow rusting will help in preventing the production of new virulences and thus remain effective longer period of time. With this objective nine varieties of T. aestivum were tested for the slow rusting mechanism against leaf rust of wheat under artificial epiphytotic conditions. Severity with type of reaction and average coefficient of infection of leaf rust varied among the varieties studied (Table 1). Varieties CC-464, DWR-39, HD 2189, and DWR-16 have shown slow rate of rust development with the terminal severity 5 MR, 5 MR, 30 MS and 30S respectively (Figure 2). varieties NI 5439, Lal Bahadur, Kalyan Sona and Sonalika have shown fast rate of rust development with the terminal severity 100S, 100S, 80S and 70S respectively (Figure 1). Thousand grain weight and net plot yield is given in Table 2. Slow rate of rust development may be due to longer latent period, decrease in size of pustules and production of less number of pustules on leaf surface. Similar type of observation was noticed by OHM & SHANER (1976) in wheat varieties against P. recondita f.sp. tritici. Yield levels (net plot yield and 1000 grain weight) differed greately among the varieties used for the study. The studies indicated that slow rusting promising varieties of wheat could be grown wherever the leaf rust occurs regularly. These varieties do offer the field resistance. The Senior author is grateful to the Indian Coucil of Agricultural Research, Krishi Bhavan, New Delhi, for providing the Junior Fellowship under Human Resource Development Programme throughout the period of investigation. References HOOKER, A.L. 1967. The genetics and expression of resistance in plants to rusts of the genus Puccinia. Ann. Rev. Phytopath., 5: 163-182. JOSHI, L.M., K.D. SRIVASTAVA, and K. RAMANUJAM, 1975. An analysis of brown rust epidemics of 1971-72 and 1972-73 (Abstr.) Indian Phytopath., 28: 138. LOEGERING, W.D., 1959. Method for recording cereal rust data, USDA, International Spring Wheat Nursery. OHM, H.W. & G.E. SHANER, 1976. The components of slow leaf rusting at different growth stages in wheat. Phytopathology. 66: 1356-1360. ROMIG, R.W. 1957. Stomatal exclusion of leaf rust of wheat. Ph.D. Thesis, Purdue University. SINGH, D.V. 1985. Modern concept of management of wheat diseases. Modern Techniques and Concept of Wheat Diseases Management, 1985. WILCOXSON, R.D. 1986. Slow rusting of cereals Problems and Progress of Wheat Pathologen in South Asia, Malhotra Publishing House p. 333-344. |
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