assessment of relationships among yield and quality traits in alfalfa (medicago sativa) under dryland farming system, hamadan, iran

seeds of 200 accessions of alfalfa (medicago sativa l.) were provided from iraniannatural resource gene bank and were sown as drilled plot using alpha designs/unreplicatedwith 2 repeated entries within all of 10 blocks under dry land farming system in agriculturalresearch center of hamadan, iran during 2009 to 2010. the data were collected and analyzedfor plant height, stem number, leaf stem ratio (lsr), node number, vegetation score, foragedry matter yield (dm yield), crude protein (cp), dry matter digestibility (dmd), watersoluble carbohydrates (wsc), crude fiber (cf), acid detergent fiber (adf), and total ash. dmyield was positively correlated with node number, plant height, stem number, vegetation scoreand negatively correlated with leaf/stem ratio, dmd(%), cp(% )and wsc(%). the factorialanalysis was based on the principal component extraction and varimax rotation method.results of factor analysis were accounted for 81% of total variance for first six factors. factor1 which was accounted for 19% of variation was associated with dmd, wsc and adf. thisfactor was regarded as quality factors. factor 2 accounted for 17% of variation was named asthe productivity factor since it included dm yield, vegetation score and leaf/stem ratio. sincethe third (cp and cf) and forth factors (plant height and node number) were important. basedon ward cluster analysis, 200 entries were divided into 7 groups. accessions in 4 clusters werecalculated well above the overall mean for dmd, cp, wsc and total ash. the accessions incluster 7 had higher values for dm yield and morphological traits. the results of this studyindicate that selection of variables in productivity factor (factor2) could enable breeders torelease the desirable increment in forage yield of alfalfa.