Identification of groundnut genotypes resistant to bacterial wilt in Vietnam

Abstract

Two hundred and ten germplasm and breeding lines and landraces of groundnut were screened for resistance to the causal organism of bacterial wilt in preliminary field trials at infested locations in northern Vietnam during 1994-1995. Selected genotypes were further evaluated during the spring and autumn of 1995 and also during the 1996 spring season. Three genotypes (ICG 8666, ICG 5273, and Gie Nhoquan) were identified as resistant at several locations; these also showed a markedly lower incidence of bacterial wilt than the susceptive cultivars Sen Nghe An and ICG 3704 in greenhouse inoculation tests with several isolates of the bacterial wilt pathogen, Pseudomonas solanacearum. Of the four isolates (QO, HT1, HTR4, and HB) of the pathogen tested, HT1 induced much higher levels of wilt in ICG 5273 than the other isolates. Four breeding lines (ICGVs 87157, 87206, 87242, and 93188) showed moderate to high levels of field resistance, but gave erratic results in greenhouse inoculation tests. The characteristic features of identified sources of resistance are described, and the importance of their utilization in resistance breeding is discussed.