No abstract

Verticillium wilt caused by race 2 of Verticillium dahliae is common in proportions) was about 5.7 ms per gram of, soil. In five other fields, California on tomato cultivars with the Ve gene for resistance to race 1. however, in which the numbers of race 2 ms were determined, a linear About 47% of 124 isolates of V. dahliae taken directly from tomato field correlation was observed between numbers of race 2 ms (0.0 to 2.0 ms/g of 'soils were race 2; the remaining isolates were either race 1 (43%) or soil) and DI (0 to 100%) when data were plotted arithmetically after nonpathogenic on tomato (about 10%). In contrast, isolates from diseased conversion of DI %to loge (1/ 1-DI) (slope = 2.Oand r =0.877). The line for tomato plants (race I resistant cultivars) from the same fields were the same data plotted on a logio-loge-logio scale had a slope of 1.0(or 1.57 predominantly race 2 (about 86% of 153 tested). Race I was more virulent if assumed to be nonlinear and transformed to logio before regression than race 2 on cultivars lacking the Ve gene for resistance (susceptible). analysis) instead of 0.66, as predicted by Baker et al (10) for abstract Average virulence of race 2 isolates was lower on cultivars with the Ve gene mathematical Model II. Thus, the models and equivalent interpretations than on susceptible cultivars. Incidence of Verticillium wilt (DI) on race I for slopes of lines in arithmetic, logio-logio and log0o-log,-0ogio plots appear resistant cultivars was essentially 100% in 46 fields where soil inoculum to be of questionable validity. density (ID) of total microsclerotia (ms) (race 1 and 2 in undetermined

No abstract

No abstract

No abstract