Multivariate Analysis of Short Day Onion (Allium cepa L.) Genotypes by Canonical Variate Analysis and Mahalanobis Distances

Genetic variability and diversity of genotypes are very important for all living organisms. Knowledge of the genetic diversity is a potential tool for pre-breeding parental selection. The present experiment was conducted at two locations (Isfahan, Khuzestan) under field conditions during the 2017–2018 growing season, with fifteen short day onion genotypes which were evaluated by multivariate methods. Nine quantitative traits were studied. MANOVA showed that the locations, varieties and location × variety interaction were significantly different for all nine traits. Significant positive correlation observed for two locations for yield and single weight (0.85 in Khuzestan and 0.61 in Isfahan), yield and bulb height (0.52 in Khuzestan and 0.55 in Isfahan), bulb height and index shape (0.68 in Khuzestan and 0.70 in Isfahan) and bulb diameter and single weight (0.81 in Khuzestan and 0.66 in Isfahan). Further, yield was significantly correlated with dry matter: positively in Isfahan (0.62), and negatively in Khuzestan (–0.54). In Khuzestan, the first two canonical variants explained 79.19% of the total variation between the varieties; however, the greatest variation was found for the Saba and Behbahan improved population. The first two canonical variables explained 86.76% of the total variation between the varieties in Isfahan. Saba and Behbahan improved population varieties were the smallest, while Paliz and Early Super Select were the largest. The Saba and Behbahan improved population, as the most diverse genotypes, were recommended for further inclusion in future crop improvement programs.