RICE SCIENCE ›› 2007, Vol. 14 ›› Issue (2): 78-84 .

• Research Paper • Previous Articles     Next Articles

A Comparative Study of SSR Diversity in Chinese Major Rice Varieties Planted in 1950s and in the Recent Ten Years (1995-2004)

YUAN Xiao-ping, WEI Xing-hua, HUA Lei, YU Han-yong, WANG Yi-ping, XU Qun, TANG Sheng-xiang   

  1. State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou 310006, China
  • Received:2007-03-01 Online:2007-06-28 Published:2007-06-28
  • Contact: WEI Xing-hua
  • Supported by:
    the State Key Basic Research and Development Plan of China(Grant No. 2004CB117201) and the Key Research Project for International Cooperation of Zhejiang Province (Grant No. 2006C24012).

Abstract: Forty pairs of SSR markers were used to compare the genetic diversity changes in 151 Chinese major rice varieties planted in 1950s and in the recent ten years. Of 40 SSR loci, 39 were found to be polymorphic while one locus (RM479) monomorphic. A total of 213 alleles were identified from the 39 polymorphic loci. The average number of alleles per locus (Na) was of 5.5, ranging from 2 to 11. Nei’s gene diversity index (He) varied drastically among loci from 0.309 at RM174 to 0.869 at RM418, with an average value of 0.649. There existed significant difference in SSR allelic diversity between indica and japonica subspecies, and indica had more variation than japonica both in Na and He. By comparison with the genetic changes in Na and He, it was revealed that the varieties planted in 1950s had more alleles and higher He than those in the recent ten years both for indica and japonica rices. The difference between two subspecies for Na was significant in a tendency over time (indica: z = 2.677, P = 0.007; japonica: z = 3.441, P = 0.001), but not significant for He (indica: z = 1.471, P = 0.141; japonica: z = 1.932, P = 0.053). Analysis of molecular variance (AMOVA) indicated that there existed significant difference (P < 0.05) in genetic variation between the two periods, of which more genetic variation was contributed by indica (Fst = 0.050) and japonica (Fst = 0.082) subsets. Using locus-by-locus AMOVA procedure, significant genetic differentiations were observed in 13 loci (RM21, RM128, RM147, RM169, RM190, RM221, RM231, RM251, RM253, RM317, RM341, RM418, and RM478) for indica varieties and 11 loci (RM101, RM135, RM152, RM159, RM169, RM190, RM251, RM253, RM311, RM418, and RM478) for japonica ones between the two periods. It was found some alleles had been lost in current major rice varieties as comparing with those in 1950s. Therefore, it should be necessary to exploit more alien elite genetic resources for extension of genetic background in current rice breeding program.

Key words: rice (Oryza sativa), major varieties, simple sequence repeats, genetic diversity, analysis of molecular variance