Study of genetic diversity and relationships between agronomic traits in lentil

Introduction Food legumes with high amounts of protein are known as the second largest source of human food. Lentil (Lens culinaris Medik.) have large amounts of protein (28%), micronutrients and vitamins in its seeds and is one of the beans in the world that is highly consumed in human diets. Also, its straw contains 2% minerals and 59% carbohydrates and considered valuable in animal feeding. Study of the genetic diversity is one of the most important steps in plant breeding program, so that the genetic diversity is considered as the basis of selection. By studying the diversity, the relationships between traits can be understood, too, and the best assays for high yielding are selected. In this regard, the morphological markers are the selection criteria. As reviewed above, the present research was carried out for studying the genetic diversity of 100 lines of lentil in terms of agro-morphological, determining the relationship between seed yield and other traits and selecting the superior pure lines using multivariate statistics methods.   Materials & Methods To evaluate the 100 lines of lentil that were imported from ICARDA, an experimental field was conducted in research station of Shahrekord University in based on simple lattice 10×10 with two replications at 2012-13 cropping season. Because of the incomplete blocks within each repeat for all characteristics were non-significant, the data were analyzed as the randomized complete block design. The studied pure lines were cultivated in late winter in 3-5cm depth and 10cm intervals on the plots which consisted of 2 rows of 1m length, and 30cm between rows. During the growth season, the weeding was done manually in several times. During the study, days to flowering and days to maturity were recorded. After the physiological maturity, 10 plants of each plot were harvested and some traits such as 100 seed weight (g), plant height (cm), number of pods per plant, weight of pods per plant (g), leaf length (cm), leaf width (cm), seed diameter (mm), stem diameter (mm), biological yield per plant (g), RWC (%) and seed yield (kg/ha) were measured. Analysis of variance, comparison of means, correlation analysis, cluster analysis, factor analysis, and estimate of Phenotypic coefficient of variability (PCV), Genotypic coefficient of variability (GCV), broad sense heritability (h2) and genetic advance (GA) were achieved to evaluate the yield performances, genetic diversity and the relationship between traits in pure lines of lentil in the present study. For above analysis, SAS software version 9.1 and SPSS software version 20 were used.     Results & Discussion The results of analysis of variance showed that high genetic variation among studied lines as the differences between 100 pure lines were significant at 1% probability level. According to the means comparison, it was not observed a desirable line in terms of all studied traits but the superior pure lines (ILL590, ILL947, ILL3963, ILL2795, ILL461, ILL459, ILL353 and ILL5888) in terms of phonological characters, stem diameter, number of pods per plant, plant height and seed yield were identified. Number of pods per plant, weight of pods per plant, leaf width and biological yield had the highest values of GCV, h2 and GA. The correlation analysis indicated that seed yield had positive and significant correlation with number of pods per plant and weight of pods per plant at 1% probability level; while its relationship with days to flowering and days to maturity was negative and significant at 1% probability level. Thirteen agronomic traits have been classified into four groups which expressed 77/97% diversity of the total variation according to the factor analysis Each of the first, second, third and fourth components were able to allocate 26.16%, 25.37%, 17.30% and 9.13% respectively. Cluster analysis using Euclidean distance with Ward's method placed the studied lines into eight groups and desirable lines in Shahrekord climate were grouped on the cluster 8.   Conclusion Identification of relationship between agronomic traits and genetic diversity can help the breeders to select the best traits and varieties. The results of this study showed significant genetic variation for agronomic traits in lines of lentil and lines ILL590, ILL947, ILL3963, ILL2795, ILL461, ILL459, ILL353 and ILL5888 had high genetic potential for increasing the seed yield. Also, the number and weight of pods per plant, days to flowering and maturity can be used to improve the seed yield in breeding programs.