Evaluation of Cold Tolerance at Seedling Stage of Oryza sativa L. Germplasm Resources from 14 Asian Countries

PurposeTo select cold-tolerant rice varieties.

Method187 cultivated rice (Oryza sativa L.) germplasm resources from 14 Asian countries were taken as research objects. According to population relationship of intraspecies group and geographical location, they were roughly divided into 4 parallel groups. The three-leaf stage seedlings were treated at 4 ℃ for 24, 36, 48 and 60 h, respectively, and the yellow leaf rate was counted after the period and the cold tolerance level was identified.

ResultAccording to the percentage of yellow leaf rate, the five cold tolerance grades of rice could be accurately identified. O. sativa ssp. japonica had better cold tolerance than O. sativa ssp. indica. The 11 strong cold-tolerant varieties were mainly distributed in high latitude or high altitude regions. The results showed that the leaf yellow rate had good diversity at 24 h and 36 h at 4 ℃, which were suitable for the whole genome-wide association analysis. The difference in cold tolerance between varieties is determined not only by genetic factors, but also by their geographical distribution and local planting strategy.

ConclusionA total of 11 low-temperature resistant rice cultivars were screened in different treatment groups, which could provide reference for genetic improvement and molecular breeding of cold-tolerant germplasm resources.