Determining the Most Important Traits Affecting Grain Yield in Iranian Anise (Pimpinella anisum L.) Populations Based on Regression Analysis and Path Analysis

In order to determine the most important components of anise grain yield using regression analysis and path analysis, an experiment was conducted with 12 anise population in a randomized complete block design with three replications at research farm of the agricultural faculty, University of Zanjan in 2014 and 2015. The evaluated traits were days to flowering, days to maturity, grain filling period, plant height, number of primary branches per plant, number of secondary branches per plant, 1000-grain weight, number of umbels per plant, umbelet numbers per umbel, number of grains per umbel, grain yield, biological yield and harvest index. Combined analysis of variance showed significant differences between the populations from the all of studied traits. Days to maturity, number of umbels per plant, number of grains per umbel, biological yield and harvest index had significant positive correlations with grain yield. Stepwise regression analysis showed that the number of umbels per plant and number of grains per umbel justify 53 percent of the grain yield variations. Also, path analysis showed that direct effects include the main portion of correlation of these traits with grain yield. Since the traits have not negative relationship together, selection of anise genotypes using these two traits can be recommended to indirect improve grain yield.