بررسي تنوع و تعيين فاصله ژنتيكي در 10 ژنوتيپ چچم يكساله با استفاده از روش هاي آماري چند متغيره

Investigation of variation and determination of genetic distance among 20 genotypes of annual ryegrass (Lolium multiflorum) using multivariate statistical methods

In order to Study of genetic variation among 20 local and foreign accessions of annual ryegrass (Lolium multiflorum),an experiment was conducted using a complete block design with Three replications in Alborz Research Center, Karaj, Iran. during 2000 and 2001. Forage dry matter yield, basal cover, ear emergence date, pollination date, stem number per plant, stem height and persistency were assessed for 5 and 2 cuts during 2000 and 2001, respectively. The data were collected and analyzed for total annual dry matter yield and average values of each morphological trait. The data were also analyzed as split plot in time over two years. Phenotypic correlations among characteristics were determined for all pair-wise combinations. Using principal component analysis and cluster analysis the accessions were classified based on 7 characters. The results showed significant differences among accessions for all of characters for individual year and combined over two years. There was a positive and significant correlation between dry matter yield with both plant height and persistency. Basal cover was negatively correlated with persistency and positively correlated with stem number. Using principal component analysis, the first three components determined 83% of the total variation. Annual dry matter yield, plant height and persistency was the most important traits in the first component. Ear emergence date and pollination date were the important traits in the second components. The 20 accessions were grouped into 4 clusters based on multivariate analysis of 7 classification variables. Accessions in cluster 1 averaged well above the overall mean for forage preduction, plant height and persistency. The accessions in cluster 2 had higher stem number and basal cover and, that increased their productivities. The accessions in cluster 3 were the late maturity groups and they ranked second for dry matter yield. Cluster 4 characterized by early maturity, lower dry matter yield, and low persistency.