Phenotypic characterization of black raspberry to select the promising genotypes

Black raspberry is a valuable fruit crop that is cultivated in many parts of the world and its fruit is directly used in agriculture, and indirectly in the food and confectionery industry. In the current study, the phenotypic and biochemical variations of black raspberry genotypes were studied with the aim of introducing superior genotypes. Significant differences were observed among the genotypes for most of the studied traits. The flowering date varied from April 28 to June 09, and the fruit ripening time was from May 26 to August 05. The highest fruit weight was 5.67 g and the lowest fruit weight was 0.43 g which showed high variation (CV = 92.94%). Total soluble solids (TSS) ranged from 4.00 to 28.00%, while the total anthocyanin varied from 79.62 to 898.40 mg/100 g fresh fruit weight. Fruit weight showed positive and significant correlations with fruit length (r = 0.93), fruit width (r = 0.86), drupelet strength (r = 0.42) and fruit shape (r = 0.39). TSS showed positive and significant correlations with the ripening date (r = 0.34) and anthocyanin content (r = 0.32), which confirms that sugar is the main contributor to anthocyanin synthesis. The principal component analysis (PCA) showed that the 10 components explained 80.12% of the total variance. Hierarchical cluster analysis grouped the genotypes into two main clusters with four sub-clusters. While the many genotypes showed potential, 18 genotypes were superior in terms of the fruit quality and can be singled out for cultivation and also are valuable gene pools for breeding programs.