Screening Cucumber Plant Introduction Accession Lines for Resistance against Cucumber Strain of Papaya ringspot virus (PRSV)

Cucumber is a popular fruit vegetable widely cultivated in Odukpani and Akamkpa local government areas of Cross River State, Nigeria, supplying the consumption needs of the nearby metropolitan Calabar City dwellers. However, its cultivation is threatened by infection by Papaya ringspot virus watermelon strain (PRSV-W). This study provides the result of screen house evaluation of USDA Plant Introduction (PI) accessions lines of cucumber for resistance to a Nigerian cucumber strain of PRSV-W. The response of the lines showed a spectrum of reactions to the virus strain from the extremely susceptible ones, that could not withstand the virus infection to the immune that were uninfected by the virus. Out of the 187 accession lines screened, 22 immune lines (PI 391570, PI 419010, PI 419017, PI 432873, PI 432877, PI 432878, PI 432895, PI 489752, PI 137845, PI 211979, PI 211984, PI 605924, PI 606010, PI 227207, PI 390253, PI 223437, PI 118279, PI 422200, PI 525152, PI 406473, PI 390952 and PI 357867) were identified. Besides, 17 others (PI 118807, PI 163217, PI 165509, PI 175121, PI 177364, PI 179263, PI 212985, PI 215589, PI 217644, PI 220791, PI 234517, PI 249562, PI 267746, PI 271326, PI 344384, PI 358813 and PI 358814) showed high tolerant and eight others were moderately tolerant to the virus. The remaining 140 PI lines were very susceptible to the virus. The identification of completely immune and highly tolerant PI accession cucumber lines in this study points the availability at the USDA germ plasm collections of potential materials that could be included in breeding programs to develop high resistant varieties of cucumber to PRSV-W.