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

To study the genetic control of hullability in sunflower (Helianthus a nnuus L.), 36 hybrids, produced by a factorial cross of six male steri le and six restorer lines, were evaluated in two locations in Spain an d one in France. Hullability was calculated as the ratio of the quanti ty of hull removed by a mechanical huller compared with total hull con tent. In dry conditions in Spain, hullability was twice (83.1%) that o bserved in France (41.5%). In all locations, male, female and interact ion effects were significant. Estimates of narrow sense heritability v aried between 0.78 and 0.82, values similar to those for other seed ch aracters such as oil content. There were positive genetic and phenotyp ic correlations between hullability and 1000 seed weight (means 0.81 a nd 0.74, respectively) but negative correlations with seed oil content (-0.73 and -0.68, respectively). It is concluded that selection in ea rly segregating generations of crosses involving good hulling material needs a specific strategy in order to maintain reasonable levels of o il and protein contents in the seed of the selected genotypes.