Study On Genetic Variation In Germplasm Resource Of Populus Deltoides

Genetic variation of 11 sib-families (145 clones) from Populus deltoides germplasm established by Nanjing Forestry University was analyzed on phenotype and molecular level, which provided the base for the polar breeding in future. The main results as follows:1. The results indicated that significant difference in height, DBH and volume characters exited among 11 sib-families and clones-within families. About 17% of the genetic diversity resulted from differentiation among families with remaining 41% residing within families. Height, DBH and volume characters of P.deltoides were middle genetically controlled with the average broad-hereditary of 3 years of 64.48%, 62.78%, 60.58%, respectively, and the average coefficient of genetic variance of 3 years of 11.26%, 11.49%,28.42%.2. A total of 103 alleles were detected using 12 SSR loci in 137 P.deltoides clones, with an average allele number of 8.6 per locus (range : 2-14) , effective allele number of 5.4 (1.6-8.8). Except for PMGC2408 and PMGC2522, all other SSR markers showed on a high value of gene diversity ranging from 0.37 to 0.89 with a mean of 0.75.The results showed that genetic diversity of families had no significant difference . 11 sib-families showed a high value of genetic identity ranging from 0.2735 to 0.7272 with a mean of 0.4814.The average coefficient of genetic differentiation (Gst) was 0.22, which showed 22% of genetic diversity resulted from differentiation among families with remaining 78% residing within families. UPMGA cluster analysis showed that 11 sib-families could be classified into two distinct classes at genetic distance 0.61. 7 sib-families that come from Mississippi were classed into class one, and class two only had 4 sib-families, coming from Louisiana. The average genetic distance was 0.61, which showed abundant genetic variation exited among 11 sib-families.3. Effect of 12 SSR loci on growth traits of P.deltoides were analyzed with PROC GLM of SAS. Results showed that 3 loci had significant effect on growth traits of P.deltoids. It appeared that some QTLs exited near of these locis.