GENETIC-STUDIES OF HULLABILITY IN COMPARISON WITH OTHER SUNFLOWER SEED CHARACTERISTICS

To study the genetic control of hullability in sunflower (Helianthus annuus L.), 36 hybrids, produced by a factorial cross of six male sterile and six restorer lines, were evaluated in two locations in Spain and one in France. Hullability was calculated as the ratio of the quantity of hull removed by a mechanical huller compared with total hull content. In dry conditions in Spain, hullability was twice (83.1%) that observed in France (41.5%). In all locations, male, female and interaction effects were significant. Estimates of narrow sense heritability varied between 0.78 and 0.82, values similar to those for other seed characters such as oil content. There were positive genetic and phenotypic correlations between hullability and 1000 seed weight (means 0.81 and 0.74, respectively) but negative correlations with seed oil content (-0.73 and -0.68, respectively). It is concluded that selection in early segregating generations of crosses involving good hulling material needs a specific strategy in order to maintain reasonable levels of oil and protein contents in the seed of the selected genotypes.