| African Rice, behaving strong resistance, vigorous vegetative growth, weed-competitive and high light utilization efficiency compared with Asian rice, is an important germplasm resource. The new possibility of creat new rice varieties with high yield will be provided by introduction of beneficial traits related genes derived from African rice. Currently, there are little reports about the study and usage of African rice, because of the reproductive barrier between the two cultivated rice species and difficulty to creat primary segregating population. In this study, the African cultivated rice introgression line populations, constructed for many years, were used as experimental materials, and of which the corresponding parent fingerprints were constructed with SSR markers. Nine yield-related traits of introgression lines, such as plant height, panicle length, grain number per panicle, etc., were measured, which combined with AFLP markers to process the correlation analysis between traits and molecular markers. The main results are as follows:1. Thirteen pairs of polymorphic SSR markers were selected from 118 pairs of primers, which amplified 89 polymorphic DNA fragments among 54 rice materals, including African rice, Asian rice and NERICA rice. PIC value range is among 0.2683-0.8624, with an average of 0.6629, indicating that the 13 pairs of SSR markers obtained are widely distributed, and have rich variation in 54 strains of rice.2. Analysis of the genetic diversity of 54 various rices, the average number of effective alleles is 4.0617, the average Shannon diversity index is 1.4846, which reveales that this group is rich in genetic diversity. Analysis of the three types of rice populations, the result shows that African rice is the most abundant genetic diversity, Asian rice population genetic variation minimum; The results of analysis of the genetic distance between African rice and Asian rice showed that the genetic coefficient of RAM3(African rice)and J23B(Asian rice) is 0.3077.3. Specific SSR markers fingerprint encoding standard were established based on which the fingerprint map of 54 core parent materials were constructed according to the amplifying results of 13 pairs of SSR primers.4. Major agronomic traits of 119 African Rice introgression lines were analyzed, the results showed that the plant height and yield per plant, 1000-grain weight, spikelets number per panicle, seed setting rate was significantly positively related, correlation coefficients of which were 0.312, 0.402, 0.199 and0.397, respectively. Significant positive correlation was conserved between grain yield per plant and spikelets number per panicle, the number of seed rate, spikelets length, panicle number, which coefficients were 0.556, 0.237, 0.429, 0.605, respectively.5. Using 55 AFLP primers amplification detection in 119 introgression lines carrying African rice genes, 20 pairs of primers were screening out, which receives 533 allele loci, including 250 with polymorphism fragments, polymorphism rate between 20.83% and 92.31%. Using polymorphism fragment analysis the genetic diversity of this group, the average Nei’s genetic diversity index is 0.3470 and average Shannon information index was 0.2198.6. Proportions of African rice genes in 119 introgression lines were calculated using the 250 polymorphic markers, which ranged from 0.76% to 12.63%, and the average of which was 5.4 %.Analysis of correlation between the proportion of African rice nuclear gene content and the yield related traits results showed that there are significantly negative correlation between proportion of African rice genes and the days from sowing to heading,setting rate, which correlation coefficients is-0.324 and-0.323. And there were significant positive correlation between the proportion and spikelets length, spikelets number per panicle, which correlation coefficients are 0.309 and 0.429.7. Correlation analysis was carried on with 250 polymorphic markers and yield related phenotypic traits. Statistical significance related markers were collected. Multiple linear regression analysis was made according to Kraakman’s multiple linear regression program for the obtained markers from correlation analysis. Thirty six markers associated with nine agronomic traits such as plant height, seed setting rate, 1000 grain weight etc. were obtained, whose contribution rates range between 9.3% and 57.95%.there were 11 markers originated in African Rice, which has three markers Ega Maag30, Ega Maag21, Ega Maag13 is the specific from African Rice.8. Using the obtained polymorphic AFLP markers combined introgression lines population linkage analysis, 10 linkage groups were obtained, the average marker interval 3.2c M, covering a total area of 167.0c M on chromosomes. There are 4 four marks Eagg Mctt1, Eaag Mtag11, Ega Maag30, Ega Maag21 which derived from the African Rice was positioned on the linkage group. |
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