Morphological Characterization and Character Association Studies in Sunflower (Helianthus annuus L.)

Abstract

Sunflower (Helianthus annuus L.) is an important oilseed crop, and the identification of genetically diverse and superior germplasm is essential for its improvement. The present investigation was undertaken to evaluate genetic variability, characterise sunflower germplasm using Distinctness, Uniformity and Stability (DUS) descriptors, and determine the association between seed yield and its contributing traits. A total of 46 sunflower genotypes, comprising 44 test genotypes and two checks, were evaluated during Kharif 2025 at the Oilseeds Research Station, Latur, Maharashtra, India. The genotypes were evaluated for ten quantitative traits, namely days to 50% flowering, days to maturity, plant height, head diameter, 100-seed weight, volume weight, hull content, seed filling percentage, oil content and seed yield per plant. Analysis of variance revealed highly significant differences among the genotypes for all the quantitative traits, indicating substantial genetic variability. The mean performance of the genotypes showed considerable variation for flowering, maturity, plant height, head diameter, seed characteristics, oil content and seed yield. High heritability coupled with high genetic advance as per cent of mean was observed for plant height, head diameter, 100-seed weight, volume weight, hull content, seed filling percentage, oil content and seed yield per plant. Genotypic and phenotypic correlation analyses revealed significant positive associations of seed yield with head diameter, plant height, 100-seed weight and volume weight, with head diameter showing the strongest association. Morphological characterisation using DUS descriptors revealed variation among the genotypes for several qualitative traits related to hypocotyl pigmentation, leaf characteristics, head attitude, ray floret characteristics and seed traits. The evaluated genotypes differed for leaf colour, leaf shape, leaf serration, seed shape, seed coat colour and seed coat stripes, whereas some descriptors showed uniform expression across the genotypes. Based on quantitative performance and morphological characteristics, RHAGPR-3, RHA 274, 93 R, RCB-5, OPH-107, CMS-90-3B, 143 R and HOC-20R were identified as promising genotypes. The present study identified substantial genetic and morphological variability among the evaluated sunflower genotypes and provided useful genetic resources for selection and future breeding programmes aimed at improving seed yield and associated traits.