Life history parameters including longevity, developmental time, and reproduction were determined for whiteflies, Trialeurodes vaporariorum (Westwood), kept in clip‐on cages on susceptible parent, Lycopersicon esculentum, resistant parent, L. hirsutum glabratum, and intermediate breeding lines of tomato. Using the Lewontin triangular reproductive function, the intrinsic rate of increase (rm) was calculated for each genotype. This is an elegant tool for detecting resistance, as it incorporates all salient factors of life history. Comparing rm to the other parameters measured, selection criteria were chosen. Developmental time is not a suitable selection criterion as it varies very little even between the most susceptible and the most resistant genotypes. Additionally, developmental time of T. vaporariorum offspring was found to be highly significantly correlated to parental age on all tomato genotypes except L. hirsutum glabratum. Total reproduction, truncated population counts, and longevity appear good criteria for selection. This test, focusing on antibiotic factors, shows large differences between the resistant and susceptible parent genotypes, but much smaller differences between the breeding lines and the susceptible parent. Earlier screenings relying on a variety of tests appear to have maintained antixenotic rather than antibiotic properties in the breeding lines.

No abstract

PI 96983 was reported to be conditioned by a dominant gene Rsv virus: Classification based on virulence in resistant soybean cultivars. (5). Resistance to all seven SMV strains transferred from PI Phytopathology 69:467-470. 360.844 to the soybean line OX670 was shown to be conditioned by 3. Cho, E. E., and Goodman, R. M. 1982. Evaluation of resistance in a dominant gene Rsv2 (1). From this study, it was not possible to soybeans to soybean mosaic virus strains. Crop Sci. 22:1133-1136. determine if the genes conditioning SMV resistance in PI 483.084 4. Hunst, P. L., and Tolin, S. A. 1982. Isolation and comparison of two and PI 486.355 were different from Rsv2; however, when PI strains of soybean mosaic virus. Phytopathology 72:710-713. 360.844 plants were inoculated with isolate C14, all 20 inoculated 5. Kiihl, R. A. S., and Hartwig, E. E. 1979. Inheritance of reaction to soybean mosaic virus in soybeans. Crop Sci. 19:372-375. plants developed severe necrotic symptoms similar to the reaction 6. Koshimizu, Y., and lizuka, N. 1963. Studies on soybean virus diseases of PI 483.084. Therefore, resistance in PI 483.084 and PI 360.844 in Japan. Tohoku Nat. Agric. Exp. Stn. Bull. 27:1-103. was probably conditioned by the same gene, Rsv2, since reactions 7. Kwon, S. H., and Oh, J. H. 1980. Resistance to necrotic strain of SMV of PI 483.084 and PI 360.844 to all the seven SMV strains and in soybeans. Crop Sci. 20:403-404. isolate C14 were similar. Since the dominant gene in PI 486.355 8. Lim, S. M. 1982. A new source of resistance to SMV in soybeans. differs from the gene in P1483.084, it probably was at a third locus. (Abstr.) Phytopathology 72:943. Further study is needed to compare these genes by evaluating 9. Milbrath, G. M., and Soong, M. M. 1976. A local lesion assay for reactions of the F2 and testcross progeny plants to SMV strains, soybean mosaic virus using Phaseolus vulgaris L. cv. Top Crop.

No abstract

No abstract