Grouping of Bulgarian and foreign cotton varieties by cluster analysis

N. Valkova, M. Koleva*

Agricultural Academy, Field Crops Institute, 6200 Chirpan, Bulgaria

(Manuscript received 2 June 2023; accepted for publication 25 March 2024)

Abstract. During the period 2016-2019, 21 Bulgarian and 10 foreign cotton varieties were included in a trial set by the block method design in four replicates and a harvest plot of 20 m2. A cluster analysis was applied to the most important economic traits. It was found that based on the clustering by individual years and on average for four years, the varieties were divided into two or three main clusters, mainly on the traits of seed cotton yield, fiber length and lint percentage. The year conditions have influenced the phenotypic manifestation of the studied traits and have had a significant impact on the genotypes clustering by the individual years. The clustering of the varieties based on the average data for four years showed different degrees of genetic similarity and distance between them and with the standard variety – Chirpan-539. The varieties Helius, Trakia, Philipopolis and Plovdiv, which were highly productive, were genetically very similar and it is appropriate to include them in one selection program together with the varieties Natalia, Dorina, Vega, Perla-267, Kolorit, (Bulgarian selection), Stoneville 112, Deltapine 30 (American) and 791-169 (Greek), which were genetically more distant from them and have shown other valuable traits.