Estimation of Mating System in Natural Oryza rufipogon Populations by SSR Markers
LI Xiao-xiang1,2; LIU Yong2, *;DUAN Yong-hong1 ; WANG Shu-hong1 ;ZHAN Qing-cai1 ;SUN Gui-hua1 ; GAO Li-zhi3, *
1Rice Research Institute, Hunan Academy of Agricultural Sciences, Changsha 410125, China; 2Graduate School of Central South University, Changsha 410083, China; 3Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650204, China; *Corresponding author, E-mail: firstname.lastname@example.org
Oryza rufipogon Griff．is the most important germplasm for rice improvement．Better understanding its mating system will provide useful information for further in situ conservation and management of O. rufipogon． By using SSR method，the genetic diversity and outcrossing rate of six natural O.rufipogon populations were estimated. The levels of genetic diversity varied among the populations, with the Nei′s diversity indices ranged from 0.3166 to 0.6075. There was a significant genetic differentiation (Fst=0.422) among the sampled populations. Two populations exhibited a heterozygosity excess, whereas the other four populations had a heterozygosity deficit. The O.rufipogon populations possessed a mixed type of mating system, although the outcrossing rate was variable among the populations. The multilocus outcrossing rate ranged from 15.1% to 418%，and the singlelocus outcrossing rate from 10.1% to 28.5%．There were significant differences between the multilocus outcrossing rate and the singlelocus outcrossing rate, and high values of correlation of paternity in the populations, indicating a considerable inbreeding existed in the populations. The correlation of paternity for the multilocus significantly differed from the correlation of paternity for the singlelocus, suggesting that there was a substructure occurred in each sampled population. Some measures for further improving insitu and exsitu conservation of O. rufipogon were also discussed.
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