Study of Genetic Diversity, Heritability and the Correlation of Different Traits in Alfalfa (Medicago sativa L.) Related to Alfalfa Weevil (Hypera postica Gyll.) Damage in Alfalfa Germplasm

In order to identify the correlation between different agronomical traits and the study of their relation using regression analysis, 46 alfalfa populations were studied in the research farm at Bu-Ali Sina University in 2013. Analysis of variance for different traits revealed a significant difference between populations for dry forage yield at the level of 1% probability. The genotypic ccorrelation coefficients of fresh forage yield with the amounts of leaf chlorophyll (SPAD) (0.952**), plant height at 10% flowering stage with fresh forage (0.987**), dry matter yield with fresh forage yield (-0.942**), dry forage yield with plant height at 10% flowering stage (0.676*) and dry matter percent (0.896*) showed significant correlations. Phenotypic correlation analysis showed a positive and significant correlation between damage percent and the number of larvae (0.767**), a negative and significant correlation between dry material percent and fresh forage yield (-0.450**). However, dry matter percent had a negative and significant correlation with dry forage yield (0.424**). The stepwise regression for fresh forage yield as dependent variable showed that dry forage yield, dry matter percent, plant height in 10% flowering stage and number of larvae were respectively entered to the model and with 89.29% of cumulative contrast coefficient confirmed the most variations of fresh forage yield. Furthermore, the maximum and minimum heritability percent was depended to the number of Larvae and dry forage yield respectively. Naragamet population (No. 30) with a high yield of dry forage and the number of larvae and also a relatively low level of damage percent among other populations could be suggested as a desirable and tolerant population