Inheritance of Resistance to Loose and Covered Smut in Hybrids of Black Mesdag with Hull-Less, Silvermine, and Early Champion Oats

Abstract

The present paper is concerned with the results obtained in an investigation of the inheritance of resistance to loose (Ustilago Auenae (Pers.) Jens.) and covered (U. levis (K. & S.) Magn.) smut in hybrids of Black Mesdag with Hull-less, Silvermine, and Early Champion oats. The variety Black Mesdag has consistently shown complete resistance to these two races of the oat smuts. It has been grown along with the hybrids in all of the experiments and, as recorded in table I, 741 plants were inoculated with loose smut and 868 with the covered, no infected plants being observed in either series. This variety has also shown resistance to nearly all the races of both loose and covered smut. On the basis of extensive data, 9 distinct races of loose smut and 5 races of covered smut have been differentiated, and not one of these has successfully attacked Black Mesdag (Reed, 1929). It is, however, susceptible to a newly discovered race of covered smut (Reed, 1932C;Reed and Stanton, 1932), and this fact emphasizes the importance of using known races of smut in studies of the inheritance of resistance in oat hybrids.In contrast to Black Mesdag, the Hull-less, Silvermine, and Early Champion varieties are highly susceptible. They have been inoculated with the loose and covered smut and grown along with the hybrids each year, the data being recorded in table I. With the loose smut, Hull-less has given 95.2 per cent infection, Silvermine 72.3 per cent, and Early Champion 95.7 per cent. With the covered smut, Hull-less has given 73.5 per cent infection, Silvermine 74.2 per cent, and Early Champion 87.8 per cent. In one or more experiments, all of these varieties gave 100 per cent infection; in individual rows, however, a few normal plants occurred. The lowest percentage of infection obtained at any time with these varieties was 52.1 per cent. It is evident that these three varieties-e-Hull-less, Silvermine, and Early Champion-are highly susceptible to the Missouri races of loose and covered smut, and thus afford 1 Brooklyn Botanic Garden Contributions No. 66. Published, at the expense of the Brooklyn Botanic Garden, out of the order determined by the date of receipt of the manuscript.Special acknowledgments are due to Miss Margery H. Udell, Miss D. Elizabeth Marcy, and Mr. L. Gordon Utter for valuable assistance in carrying out the experimental details of these investigations.

Inheritance of Smut Resistance in Some Oat Hybrids

“…In many oat hybrids between resistant and susceptible varieties one factor for inheritance appears to be involved. Hybrids of the second, third, and fourth generations of Black Mesdag and Hull-less, Silvermine and Early Champion, inoculated with race 1 of either the loose or covered smut, indicate a single factor as the basis for the inheritance of smut resistance (Reed, 1925(Reed, , 1928(Reed, , 1934. Similar results were obtained with hybrids of Black Mesdag and Monarch Selection inoculated with the loose smut (Stanton, Reed and Coffman, 1934).…”