The Inheritance of Resistance of Oat Hybrids to Loose Smut

Abstract

The study of the inheritance of disease resistance constitutes a problem of great economic and scientific interest and numerous investigators have contributed towards its elucidation in various groups of diseases. The present paper is concerned with studies on the inheritance of resistance to the loose smut of oats, Ustilago Avenae (Pers.) Jens., in a hybrid between a very susceptible variety, Avena nuda L. var. inermis (S.N. 30), and a very resistant one, A. sativa L. var. Black Mesdag (S.N. 70). Although the results here described relate to a single cross, investigations are in progress on additional ones between the same parents, as well as crosses involving other varieties. A few results on oat smut inheritance have previously been recorded. Wakabayashi (18) has pubiished some data on the behavior of the progeny of a cross between Red Rustproof and Black Tartarian to Ustilago levis (K. & S.) Magn., the former being resistant and the latter susceptible to the smut. No smut was observed among the F1 and F2 plants. In the F3 generation, however, twelve families out of a total of ninety-five were observed to contain a few infected individuals. Barney (1) has recorded more extensive data on three different oat crosses. One cross involved two very resistant varieties, Fulghum and Black Mesdag; a second cross was between the resistant Burt and the susceptible Swedish Select; and the third cross was between two susceptible varieties, Turkish Rustproof and Golden Rain. Barney interpreted his results on the basis that resistance in the first cross depended upon three different factors, in the second upon two, and in the third upon only one. Reed and Stanton (16) have described their results with a cross between