Study On The Genetic Diversity Of Main Cultivated Wheat Varieties In The Past Forty Years Of Jiangsu Province

Wheat genetic resource is an important foundation of wheat breeding, which plays an essential role in the wheat genetic diversity research. In this study,90major wheat cultivars farmed in Jiangsu province in recent40years were used. Their genetic diversity of different periods, ecological regions and genomes were analyzed by microsatellite markers. Comparative analysis on genetic diversity of Ningmai and Yangmai series varieties (the two main wheat series of Jiangsu province) were also conducted. The main results are as follows:1. The138SSR primers evenly distributing on the chromosomes of wheat were used to reveal the genetic diversity. A total of542alleles of loci were detected from the cultivars. The average alleles per locus were3.93which varied from2to11. The polymorphism information content (PIC) value ranged from0.0326to0.8245, with an average of0.4151.2. The PIC value for31SSR loci (22.5%) ranged from0.3000to0.4000; for25SSR loci (18.1%), the value varied from0.5000to0.6000; and only for7SSR loci (5.07%), the value were more than0.7000. The PIC values of major wheat cultivars of Jiangsu province had a relatively expansive range, but the loci with higher PIC value were few.3. According to different wheat-growing ecological regions, the90wheat cultivars can be divided into two parts:cultivars of Northern-Huai River Wheat Region (NHRWR) and cultivars of Southern-Huai River Wheat Region (SHRWR).520alleles were detected and the average alleles per locus were3.77in the45cultivars of NHRWR, and the PIC value ranged from0to0.8562with an average of0.4287. And total488alleles were detected and the average alleles per locus were3.93in the45cultivars of SHRWR, the PIC value ranged from0to0.7620with an average of0.3566. Variance analysis showed that the gene diversity and the PIC value of the SHRWR were lower than NHRWR (P<0.01). The gene diversity of90cultivars, which were divided into four periods (before1980s,1980s,1990s and after2000s), were increased from0.4297to0.4541, and the PIC of each period were also accordingly increased from0.3818to0.4079. Variance analysis showed no difference among the four periods, whereas the cultivars of NHRWR and SHRWR in the four periods showed different tendency.4. Genetic diversity of19Yangmai and10Ningmai series varieties in the Southern-Huai River Wheat Region was analyzed. A total of386alleles were obtained by138SSR primers in Yangmai series varieties, and the average alleles per locus were2.95. The gene diversity and the PIC value was0.3638and0.3194respectively. Both lower than the average value of Southern-Huai River Wheat Region. A total of369alleles were detected in Ningmai series varieties, the average alleles per locus were2.82, and its gene diversity and the PIC value were0.4185and0.3673respectively, which were both higher than the average value of Southern-Huai River Wheat Region. Variance analysis showed that there was a significant different between the two series varieties at level0.05.5. Comparing the three genomes of the germplasm in all cultivars, the average allele richness was B (4.50)>A (4.08)> D (3.63), and the PIC was B (0.6700)>A(0.6632)>D (0.6599).