Evaluation of sugar beet genotypes for root traits by principal component analysis and cluster analysis

Sugar beet is the most important crop for sugar production in Europe. Wide genetic variability is essential in sugar beet breeding programs. The aim of this study is to evaluate variability for the main root traits and differences between monogerm and multigerm sugar beet genotypes from the breeding collection at the Institute of Field and Vegetable Crops. The following traits were analyzed: root weight (g), dry matter content (%), root head weight (g), root/head ratio (%), number of cambial rings, root length (cm) and root diameter (cm). Mean values for two years per genotype were standardized and used for analysis. Principal Component Analysis (PCA) and Cluster Analysis (CA) were used to examine the level of diversity for 20 genotypes and to rank the contributions of the variables. According to CA genotypes could be placed into five main groups, where a large number of multigerm genotypes were put in one group. On average multigerm genotypes were characterized by higher mean values for root weight, length, diameter and lower root head ratio. Multigerm genotypes had higher coefficients of variation for nearly all measured root traits