Abstract:

Seedling inoculation was carried out about 148 rice landraces, grown in two different periods in Hani’s terraced fields in Yuanyang County, Yunnan Province, including 72 ones that used to be grown during the 1970's (past-grown landraces) and 76 ones that had been grown during the past decade (current-grown landraces), using the two physiological races 007 and 017 that caused relatively high blast frequency in Yunnan rice production. For the race 007, the resistant proportion of the current-grown landraces (65.8%) was lower than that of the past-grown landraces (76.4%). And for the race 017, the resistant proportion of the current-grown landraces (52.6%) was also lower than that of the past-grown landraces (77.8%). In a word, the proportion of blast resistance of the current-grown landraces was lower than that of the past-grown landraces. The pathogenicity on the current-grown landraces of race 017 from the indica-japonica cross-regions was stronger than that of race 007 from the japonica regions, with the number of blast resistant varieties accounting for 52.6% and 65.8% of the total landraces respectively. Therefore, 5 landraces like ‘Laojingnuo’, ‘Zinuo’, ‘Changmaoxiang’, ‘Lengshuigu’ and ‘Yaduogu’ with sustaining blast resistance, which were identified same landraces from two different periods, for the same phenotypic traits and one-to-one correspondence relationship, which could be used for further research and breeding.