Visual analysis of sorrel (Rumex spp.) genotypes by the biplot method using morphological characters

Sorrel (Rumex spp.) belongs to Polygonaceae. It is distributed worldwide and used as vegetable crop and medicinal plant, so considerable research has been dedicated to its cultivation. Forty-four accessions from the Institut für Pflanzengenetik und Kulturpflanzenforschung (IPK), Germany, and ten genotypes collected from some areas of Iran were grown in two separate trials. The trials followed a completely randomized scheme with three replicates in a greenhouse environment. Seven traits were assessed: leaf length, blade length, lamina area, number of veins, petiole diameter, number of leaves, and dry leaf weight. The genotype × trait interaction (GTI) biplot model accounted for 77 and 78 % of the observed variability in the first and second trials, respectively. A nonagon and a heptagon were identified in trials, respectively, while genotypes 16 and 23 showed high mean values of dry leaf weight in the first and second trials, respectively. Genotypes 44 and 50 were identified as perfect genotypes, highly promising for sorrel genetic improvement programs, especially with regard to leaf yield. As for discriminative capacity, as well as typical potential, lamina area and petiole diameter best demonstrated differences among genotypes as perfect traits in both trials. There was a moderate positive correlation between dry leaf weight and lamina area across both trials (r = 0.57 for the first trial and r = 0.49 for the second trial). Therefore, lamina area can be considered an informative trait for constructing a selection index to improve leaf yield, along with dry leaf weight. The results demonstrate that lamina area and petiole diameter are key traits for selecting high-yielding sorrel genotypes, and the GTI biplot provides a practical visual approach to identify superior genotypes, facilitating efficient selection in breeding. Such a strategy can be recommended for future studies to describe prognostic and meticulous selection methods in order to recognize best traits for the breeding of sorrel and other vegetable crops.