ISHS Acta Horticulturae 521: XXV International Horticultural Congress, Part 11: Application of Biotechnology and Molecular Biology and Breeding - Gene Expression and Molecular Breeding, Genome Analysis.
GENE SOURCES OF POWDERY MILDEW RESISTANCE IN CUCUMBER |
| Authors: | M. Morishita, K. Sugiyama, T. Saito |
| Keywords: | cucumber, gene sources, powdery mildew, resistance |
| Abstract:
Most of the Japanese commercial varieties for plastic house cultivation are susceptible to powdery mildew caused by Sphaerotheca fuliginea between autumn and spring, while most of the present summer cucumber varieties have resistance to it. This study was carried out to find the cucumber gene sources which express resistance in plastic house cultivation between autumn and spring in Japan, and to analyze the inheritance of powdery mildew resistance. Three hundred accessions of cucumber were evaluated for powdery mildew resistance under two different temperature conditions, 26°C and 20°C, by using cotyledons and first true leaves. Forty-four accessions had a high level of powdery mildew resistance at 26°C, and 4 of these also showed a high level of powdery mildew resistance at the 20°C condition. PI197088–5, segregated from PI197088, showed the highest level of powdery mildew resistance in all the accessions tested here. In order to analyze the inheritance of powdery mildew resistance, PI197088-5 as a resistant parent and Sharp One as a susceptible parent were used. The mildew test of F1, F2, BC1 progenies by artificial inoculation were performed under 26°C and 20°C conditions, respectively. As a result it was thought that resistance to powdery mildew was controlled by two recessive genes, and plants with aabb show resistance under both 26°C and 20°C conditions and plants with aaBB or aaBb show resistance under 26°C condition and are susceptible under 20°C. From this study, the authors are convinced that PI197088–5 is a novel gene source for resistance to powdery mildew of plastic house cucumbers between autumn and spring in Japan. | |
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