Genetic Variation and Principal Component Analysis for Morphological and Phenological Traits in some Grasspea (Lathyrus sativus) Genotypes

Genetic variation of 20 genotypes (15 exotic collected from ICARDA, and 5 endemic collected from various regions of Iran: Ardebil, Oshnaviyeh, Qazvin, Shahre Kord and Mashhad) were studied during the 2007-2008 growing season, using morphological and phenological traits. The resultant data were examined for normality test and were then analyzed according to randomized complete block design (RCBD) with 3 replications. Mean comparisons were carried out, using Duncan's test. ANOVA showed high significant between-genotypes differences for the most traits studied. The economic yield showed the most significant positive correlations with total pod weight, plant weight during seed harvest and total pod numbers. The same correlations were true between biologic yield and plant weight during seed harvest, weights of total pod and cortex and total pod numbers. Moreover, harvest index showed the most significant positive correlations with economic yield, total pod numbers and weight, and hundred pod weight. Path analysis indicated that the plant weight during seed harvest had a direct and positive effect on either economic yield or biologic yield. The results suggested that breeding strategies for increasing seed yield in Lathyrus should consider the presence of plant weight during seed harvest and for increasing biologic yield should consider the presence of total pod weight. The principal component analysis (PCA) showed that the first 2 components accounted for the 69.1% of total variations. Euclidean distance and group average linkage (UPGMA) phenogram constructed on the basis morphological and phenological data distance showed 3 major clusters. The first comprised of 16 genotypes (G1-G16), the second contained 3 genotypes (G17-G19), while G20 genotype was separated by the third cluster. The resulting genotypes arrangement was fully fited with that obtained from the PCA.