GENETIC-MAPPING OF A LOCUS (HYP) AFFECTING SEED HYPODERMIS COLOR IN SUNFLOWER

Sunflower (Helianthus annuus L.) seed color is determined by pigmentat ion of three layers of the pericarp (hull): epidermis, hypodermis, and phytomelanin layer. A gene with major effects on hypodermis color was reported previously. How ever, genetic factors that determine the pre sence or absence of pigment in the hypodermis have not been reported. We identified RFLP markers linked to factor(s) affecting hypodermis pi gmentation and assessed the relationship between this trait and oil pe rcentage in sunflower seed. An F-2 single-cross population was produce d from homozygous and homogeneous inbred parents ZENB8 and HA89, with pigmented and unpigmented hypodermis, respectively. Two hundred sixty- seven F-2 plants and their F-3 families were evaluated. A dominant fac tor (Hyp) determining the presence of white pigments in the hypodermis was located to Linkage group 'G'. Seeds with white hypodermis had low er oil percentage than those with unpigmented hypodermis. The Hyp fact or was Located in the same map interval as one QTL with major effects on seed oil percentage in this population. Knowledge of genetic linkag e among DNA markers, hypodermis pigmentation, and oil percentage shoul d enhance breeding programs.