VIEW ARTICLE

Ecology and Epidemiology

Temperature and Host Effects on Latent and Infectious Periods and on Urediniospore Production of Puccinia recondita f. sp. tritici. J. R. Tomerlin, Formerly agricultural research technician, U.S. Department of Agriculture, Agricultural Research Service, Department of Plant Pathology, Kansas State University, Manhattan 66506, Present address: USDA-ARS, Plant Genetics and Germplasm Institute, Field Crops Laboratory, Beltsville Agricultural Research Center, Beltsville, MD 20705; M. G. Eversmeyer(2), C. L. Kramer(3), and L. E. Browder(4). (2)(4)Research plant pathologists, USDA-ARS, Department of Plant Pathology, Kansas State University, Manhattan 66506; (3)Professor, Division of Biology, Kansas State University, Manhattan 66506. Phytopathology 73:414-419. Accepted for publication 10 September 1982. This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 1983. DOI: 10.1094/Phyto-73-414.

Effects of temperature and host growth stage on development of Puccinia recondita f. sp. tritici culture UN02-64A on the wheat cultivar Thatcher (TC) and near-isogenic lines LR16(TC) and LR18(TC) were determined. Latent and infectious periods were lower on seedlings and flag leaves at higher than at lower temperatures. Generally, latent and infectious periods were shorter on seedlings than on adult plants. Cumulative urediniospore production per uredinium 14 days postinoculation (PI) on seedlings of TC and LR18(TC) was lower at lower temperatures in the 21.1- 29.4 C range. No marked effect of temperature occurred over this range on LR16(TC) seedlings. Cumulative urediniospore production per uredinium 14 days PI was depressed at temperatures below 21.1 C, particularly on LR18(TC). Total sporulation on LR16(TC) seedlings was slightly depressed at temperatures above 21.1 C, whereas total sporulation on TC seedlings was slightly stimulated at 23.9 and 26.7 C. Total sporulation on LR18(TC) seedlings was lower at 21.1 than at 29.4 C and much lower at 15.6 and 18.3 C. Total sporulation on TC inoculated at either heading or anthesis was lower at higher temperatures in the 21.1- 29.4 C temperature range. This response was not as marked on LR16(TC) or LR18(TC). Cumulative sporulation 14 days PI was greater on seedlings than on adult plants, but infectious period was longer on flag leaves, so total sporulation on adult plants was generally greater than on seedlings. Higher temperatures resulted in shorter latent and infectious periods, indicating that at higher temperatures, a leaf rust epidemic could proceed quickly, but that each generation would be shorter lived than at lower temperatures.