Cluster analysis in soybean varieties classification by economic characteristics

The aim of the study was to improve the method of soybean collection material assessment with the purpose of choosing pairs for hybridization using cluster analysis, to cluster samples according to the duration of growing period, plant height, the height of lower pod attachment, stem thickness in the lower part, the number of branches and productive joints on a plant, the number of pods and seeds per plant, the number of seeds in a pod, seed weight per plant, yield (g/m2 ), and the resistance to lodging and bean cracking. Based on the conducted cluster analysis of one hundred and forty-five soybean collection samples concerning the determined signs, it has been established that the collection material was distributed within five clusters. Soybean genotypes have been singled out as carriers of a high level of quantitative characteristics, especially the signs of yield potential which can be used as a promising selection material. The samples having analogous set of signs in the cluster and reliable distinction from others have been united in a separate cluster. The samples of the first cluster in the collection are characterized by average and close to average values of all the studied characteristics. The samples of the second cluster are characterized by high values as to the number of branches and productive joints on a plant and also the number of beans per plant. The third cluster consisted of samples having high values of the number of seeds in a bean. However, as to other signs, the samples of this group have low values. The samples of the fourth cluster are later-maturing, than those in the first three groups. They are characterized by larger plant height and the height of lower bean attachment. The fifth sample cluster is distinguished by the longest growing period and high values of the majority of signs except the number of seeds in a bean and also resistance to lodging and bean splitting. The parent forms were in four clusters out of five ones. The cluster analysis helped to conduct the choosing of parent pairs for hybridization and creation of soybean new initial material. The advantage of cluster analysis consists in being able to identify collection samples in balance according to the complex of valuable economic characteristics, rather than single out genotypes according to separate quantitative signs.Key words: soybean, selection, collection, sample, cluster, cluster analysis, initial material.