Date of this Version
Peltier, George L. (1923) A study of the environmental conditions influencing the development of stem rust in the absence of an alternate host. II. Infection studies with Puccinia graminis tritici form III and form IX (Research Bulletin: Bulletin of the Agricultural Experiment Station of Nebraska No. 25)
Stakman and Levine have shown that Puccinia graminis tritici (Pers.) Erikss. and Henn. consists of a number of biologic forms, which can be determined by their action on different varieties of Triticum species. To date 37 such biologic forms have been identified by them through the parasitic action on 12 differential hosts chosen from a large number of varieties of Triticum species. To determine whether these biologic forms remain constant in their behavior under various environmental conditions, a detailed study of the host-parasite relation was undertaken with 2 of these forms. At the same time an opportunity was afforded to determine the influence of environmental factors on the growth of the host plants and on infection and development of the disease. The various soil and air temperatures employed were held constant in all instances. The same soil moisture was maintained in all experiments where it was controlled. In all experiments the relative humidity was maintained between 95 and 100 per cent. Sunlight varied from day to day, but the total hours of sunshine was recorded for each experiment.