Application of Gamma Induced Mutation in Breeding Potato for Bacterial Wilt Disease Resistance

Abstract

Aims: Potato (Solanum tuberosum L.) production in Kenya has not been achieved in its full potential due to susceptibility of potato varieties to pest and diseases among others. Bacterial wilt, caused by Ralstonia solanacearum in potato is regarded as an important disease contributing to significant yield reduction. The disease is considered more difficult to control in field crop production using universal control measure due to pathogen’s properties as a soil-borne bacterium, broad host range and the genetic variation level within the strains. The objective was to screen potato mutants at M1V4 mutant populations for resistance against bacterial wilt using pathogenicity test. Study Design: The experimental design used was an alpha lattice with twenty three blocks each having seven plots with three replications each. Data were subjected to analysis of variance using SAS statistical package, version 9.1 and mean separation done using Duncan Multiple Range Test (DMRT) whenever there were significant differences. Place and Duration of Study: The study was carried out at Kenya Agricultural Livestock and Research Organization (KALRO), Kabete station for one season (December 2015 to April 2016) Methodology: One hundred and sixty three mutants developed from three commercial varieties (Asante 72, Mpya 43 and Sherekea 47) were evaluated. Results: The reactions of potato mutants to bacterial wilt varied from variety to variety and mutants to mutants. None of the Asante, Mpya and Sherekea mutants used was found to be resistant to bacterial wilt though Asante mutant populations showed better response. There was significant difference in some traits such as DTOW, AUDPC and PSTTN across the three potato mutant populations. Conclusion: The variation within the potato mutants and response to bacterial wilt resistance levels could be attributed to different dose rates and the reaction of each variety to the mutagen used. Since mutation is random its effects are enormous.