Assessment of variation in seed morphological traits in Phaseolus sp. landraces from western Anatolia

Abstract

Seed size, seed shape and seed colour are easily discernible phenotypic traits of beans in the market. Consumers often have specific preferences to different combinations of seed size, shape and colour. Local landraces are usually grown for their desired organoleptic and seed properties by consumers. This study investigated the variability in seed size attributes, seed shape, visual seed colour properties and seed luminosity/chromaticity properties of the germplasm of 255 landraces representing major local bean types grown in 20 provinces in Western Anatolia Region of Turkey. Measurements were made on seeds from representative single plants for seed size index, 100 seed weight, seed length, seed width, seed thickness, seed width in cross section, seed shape, seed degree of curvature in kidney types, seed shape in cross section, number of seed colors, main seed color, secondary seed colour, distribution of secondary seed color, seed veining, colour of hilum ring and values of L (Luminosity), chromaticity a*, chromaticity b*, chroma (C) and hue angle. Data were statistically analysed, principle component analysis was carried out, the germplasm was classified by UPGMA dendograms and selections were made on the bases of GGE biplot analysis. Landraces showed a considerable diversity for seed size, seed shape and seed colour trait measured. All seed size variables ranged by 2–10–fold within the germplasm. 100–seed weight ranged ten–fold from very small seeded Meso–American types (18.4 g, e.g. AYD–8, KTH–30, MGL–1, DNZ–1 and BRD–24) to very large seeded Andean types (182.3 g, e.g. MGL–37, PKS–1, ANT–33, MGL–31 and ANT–16). Seed shape also varied as kidney–shaped (96 landraces), circular to elliptic (73), circular (58), elliptic (27) and rectangular (1) shapes. Main and secondary seed colours had considerable variation within the germplasm with 151 landraces had white, 31 grey, 31 beige, 23 brown, 8 violet, 5 red and 4 black main seed colour whereas 24 landraces had violet followed by 17 black and 14 red secondary seed colour. Landraces exhibited a large variation for chromaticity and luminosity variables. L value ranged between 20.3 and 90.1 representing a 4.5–fold variation. The landraces in the germplasm were assessed and characterised on the bases of diversity in seed morphological traits. Selections were made using UPGMA dendogram and GGE–biplot for production and breeding bean cultivars for preferences of changing consumer demands. Keyword: Beans, seed size, seed shape, seed colour, luminosity, chromaticity.