Variability on percentage of seed hulls of castor seed and its importance to breeding

Abstract

Reduction on seed hull weight in relation to total seed weight has been used as strategy for increasing oil content in oilseed crops like sunflower. In order to measure the variability of seed hull percentage and seed weight, as well as the correlation between these variables, weight of seed and percentual of seed hull was measured in the cultivars BRS Paraguaçu, BRS Nordestina, BRS Energia, Epaba Ouro, AL Guarani, Mirante 10, Guarany, Lyra hybrid, CNPA 93-168 line and wild castor plants collected at Campina Grande-PB. Samples with 20 g of seeds were analysed in a completely random design with five replications. It was observed a high variability in both variables. The seed hull percentage ranged from 28.80% (BRS Energia) to 21.05% (Epaba Ouro) and the seed weight ranged from 0.852 g (BRS Paraguaçu) to 0.205 g (wild plants). It was also observed a negative correlation between these variables (r² = -0.77). The high variability observed in the seed hull percentage of brazilian castor genotypes is an indication that it is possible to increase the seed oil content by selecting materials with lower participation of hull weight on the total seed weight, following the same procedure used by breeders of others oilseed crops.