Association Mapping and Sequential Path Model for Studying Interrelationships Among Yield and Related Characters in Confectionery Sunflower (Helianthus annuus L.)

This study was carried out in order to examine the contrastive relationship between seed yield and agro-morphological traits in confectionery sunflowers at molecular and phonotypical level via association mapping and sequential path model. In this study, 50 confectionery sunflower populations gathered from different regions of country were studied in completely randomized design with ten replications under pot conditions in 2012-2013. Some traits including flowering date, physiological maturity date, number of leaves, leaf length, petiole length, leaf width, plant height, stem diameter, head diameter, head dry weight, aerial part dry weight, harvest index, 100-seeds weight, single seed weight, dehulled kernel weight, dehulled kernel weight to whole kernel weight ratio, seed length, seed width, and seed dry weight per plant were measured and calculated. Path analysis revealed direct effects of head dry weight and head diameter on seed yield. Based on Bayesian model, the whole confectionery sunflower populations were classified into three sub-populations. In order to identify molecular markers associated with gene controlling agro-morphological traits variation, association mapping was carried out via mixed linear model (MLM). Some common makers were identified among yield and agro-morphological traits; six common loci between seed yield and 100-seeds weight, one common locus between head diameter and head dry weight, head dry weight and dehulled kernel weight to whole kernel weight ratio, seed width and 100-seeds weight, leaf width and head dry weight, leaf width and seed yield. Identification of common markers between yield and agro-morphological traits confirm the correlations observed at the phenotypic level.