Assessment of genetic diversity of white lupin (Lupinus albus L.) accessions based on agro-morphological traits Sofia Petrova Institute of Plant Genetic Resources “Konstantin Malkov”- Sadovo corresponding author: soniapetrova123@abv.bg Introduction Lupinus is a relatively large genus and one of the most geographically widespread with a rich diversity of species. Lupin is an annual or perennial legume belonging to legume family, Fabaceae, one of the oldest crops. In our country lupin is not a traditional crop, but it has been used for a long time as a green manure source. The conservation and preservation of the white lupin genetic resources are of crucial importance for the breeding programs aiming the cultivar improvement. The aim of this study was to assess the genetic diversity of ten white lupin accessions regarding components of productivity and biological traits. Material and Methods Ten white lupin genotypes were used for this study. At maturity was measured following morphological traits: plant height, height to the first pod, number of productive branches, number of pods per plant, number of grains per plant, number of grains per pod, mass of grains per plant and mass of 100 grains. The phenological traits were assessment by coefficient of earliness. For ultra early varieties the value of this coefficient was from 1.00 to 1.17, for the early varieties from 1.17 to 1.33, for middle-early ones from 1.34 to 1.66 and for the late varieties was greater than 1.66. The studied agro-morphological traits were processed mathematically by analysis of variance. To investigate the genetic diversity between the studied lupin accessions was used Cluster analysis. Results and discusion The clustering of the lupin accessions based on their morphological traits is presenting on Fig. 1. The traits data are given on Table 1. The accessions were divided into two main groups (clusters). Only the accession BGR3080 was included in the first cluster. This genotype had large grains, big mass of grains per plant and big number of grains per pod. The second claster was divided into two sub-clusters. The first sub-cluster included three genotypes, with tall plants, big number of productive branches and big mass of grains per plant. The BGR 3086 genotype differed significantly by plant height. This accession also had a high number of grains per plant and the shortest vegetation period. The accession BGR6341 had significant differences by plant height, number of productive branches, number of grains per plant and mass of grains per plant. This accession characterized also by high values of number of pods per plant and number of grains per pod. The BGR 3085 accession had significant differences by mass of grains per plant. The second sub-cluster included six accessions possessing medium-high to short stem and medium-large to large grains. The data showed that within this sub-cluster significant genetic distance was observed between the genotypes. The clustering of the agro-morphological traits of the lupin accessions is presented on Fig. 2. From the clustering of the traits we could concluded that they were combined into two main clusters. Only vegitation period was included in the first cluster. The second cluster was divided into two sub-clusters: the first sub-cluster included the following traits: plant height, number of grains per plant, germination-beginning of flowering, mass of 100 grains and height to the first pod united by the close value of the Euclidean distance. The remaining four were combined into the second sub-cluster. Accession Plant height, сm Height to the first pod, cm Number of productiv branches Number of pods per plant Number of grains per plant Number of grains per pod Mass of grains per plant, g 100 grains mass, g BGR 3083 53.29 28.00 2.14* 8.71 35.00 4.49 13.23 37.80 BGR 6339 51.57* 23.43* 3.14 10.14 40.29 4.77 14.84 37.05 BGR 6337 55.43 22.57** 3.57 11.57 45.43 4.80 14.43 32.45 BGR 3080 63.86 28.14 3.14 12.14 47.43 4.90