Abstract:

【Objective】 The tolerance of some rice varieties and O.rufipogon in Gaozhou to aluminum was studied. The experimental varieties of Al-tolerant and Al-sensitive ones were distinguished and Al-tolerant accessions of O.rufipogon in Gaozhou were also screened out. The materials for mapping the genes related to Al-tolerance of O.rufipogon in Gaozhou were tested. 【Method】 In this study, seedling roots of varieties and O.rufipogon accessions or regenerative roots from tillerings of O.rufipogon were treated in 0.5 mmol?L-1 CaCl2 solution with 50 μmol?L-1 Al3+ for 1 d, the relative root elongation (RRE) was used as a parameter to evaluate the aluminum tolerance. 【Result】 Relative root elongation (RRE) of 17 rice varieties were significantly affected by genotypes, Al3+ contents and treatment time (P＜0.0001). Nipponbare, L202, Liaojing944, and 88B were Al-tolerant varieties. It is the reliable method to evaluate Al-tolerances of different genotypes in rice with the parameter RRE of seedlings which growing in 0.5 mmol?L-1 CaCl2 solution with 50 μmol?L-1 Al3+ for 1d. Besides, RRE values of 69 accessions of O.rufipogon in Gaozhou were significantly different (P＜0.0001), 55 accessions were Al-tolerant with RRE≥0.50. Compared with Nipponbare, an Al-tolerant control variety, RRE values of 37 accessions were larger than that of Nipponbare (RRE＝0.6198) and the largest RRE was 1.8730 of GZW020. Analyzing RRE values of regenerative roots from tillerings of 17 accessions of O.rufipogon in Gaozhou, it showed that 13 accessions were Al-tolerant with RRE≥0.50. Meanwhile, the correlation between RRE value of seedlings and RRE value of tillerings of the same accession was significant (R= 0.76012, P=0.0041). It is considered that some accessions of O.rufipogon in Gaozhou contain Al-tolerant genes. Furthermore, Al-tolerance was detected in 2 lines in BC3F2 generation between Huajingxian74, an Al-sensitive variety, and GZW087, one of the Al-tolerant accessions of O.rufipogon in Gaozhou. This indicates that Al-tolerance in GZW087 could be transferred into the backcross generations. 【Conclusion】 Al-tolerance is significantly different among rice varieties. There are abundant Al-tolerance accessions in O.rufipogon in Gaozhou. It has layed an important material foundations for Al-tolerance gene mapping and innovation of rice germplasms in future.

Key words: Oryza sativa L., O.rufipogon, Al-tolerance, relative root elongation