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Resistance

Transgressive Segregation of Length of Latent Period in Crosses Between Slow Leaf-Rusting Wheat Cultivars. Tae Soo Lee, Former graduate student, Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN 47907; Gregory Shaner, professor, Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN 47907. Phytopathology 75:643-647. Accepted for publication 11 December 1984. Copyright 1985 The American Phytopathological Society. DOI: 10.1094/Phyto-75-643.

Six slow-rusting wheat cultivars were intercrossed to determine whether each cultivar possessed unique genes for long latent period during infection by Puccinia recondita. All crosses showed transgressive segregation. Within some transgressively segregating F₂ populations, some plants had latent periods shorter than either parent and as short as that of the fast-rusting cultivar Morocco. Other F₂ plants had latent periods longer than either parent and as long as that of the very slow-rusting cultivar CI 13227. These results indicate that most of the genes conditioning long latent period in these six cultivars differ from each other and that they show additive effects. Wheats with very long latent periods can be obtained by making crosses among different slow-rusting wheat cultivars.