Study of genetic variation of rice genotypes on the germination components and seedling growth in the drought stress condition

The present study was conducted to study genetic diversity in 26 rice genotypes (lRRl heat tolerant collection) in 2016 in Khuzestan Agricultural and Natural Resources Research Center as a factorial experiment based on a completely randomized design with three replications including 24 lines and 2 hybrids as the first factor and drought stress with PEG 6000 in 5 levels of zero (control), -0.3, -1.8, -3.3 and -4.8 Bar were performed as the second factor. The results of analysis of variance showed that there was a significant difference between drought levels, genotypes and their interaction in all traits at a probability level of one percent. The lowest indices of germination and seedling growth were observed at the level of -4.8 Bar. The highest positive and significant correlation (r = 0.90**) was obtained between shoot length and seedling length. In principal component analysis, the four first components accounted for 85% of the total diversity. Cluster analysis with Ward method included genotypes in three clusters. In the first cluster of lines 48, 15, 35, 44, 42, 20, 19, 5, 28, 10, 16, 4, 2, 55, 53, 31, 34, 36 and HB2 hybrid, in the second cluster of lines 25 and 23 and hybrid HB1 and in the third cluster were lines 40, 13, 41 and 21. According to the results of mean of comparison, biplot and cluster analysis of the second cluster genotypes in terms of germination rate, shoot length, root length, seedling length, seedling fresh weight, seedling dry weight, seedling Dry/wet weight ratio, seed vigor index are higher than the total average and therefore tolerate to drought. The selected genotypes can be considered in advancing breeding programs in the development of new rice cultivars with greater tolerance to drought stress.