Identification of high seed oil yield and high oleic acid content in Brazilian germplasm of winter squash (Cucurbita moschata D.)

Cucurbita moschata D. seed oil contains approximately 75% unsaturated fatty acids, with high levels of monounsaturated fatty acids and antioxidant compounds such as vitamin E and carotenoids, constituting a promising food in nutritional terms. In addition, the Brazilian germplasm of C. moschata exhibits remarkable variability, representing an important source for the genetic breeding of this vegetable and other cucurbits. The present study evaluated the productivity and profile of the seed oil of 91C. moschata accessions from different regions of Brazil maintained in the Vegetable Germplasm Bank of the Federal University of Viçosa (BGH-UFV). A field experiment was conducted between January and July 2016. The accessions showed high genetic variability in terms of characteristics related to seed oil productivity (SOP), such as the weight of seeds per fruit and productivity of seeds, providing predicted selection gains of 29.39 g and 0.26 t ha^-1, respectively. Based on the phenotypic and genotypic correlations, a greater SOP can be achieved while maintaining a high oleic acid concentration and low linoleic acid concentration, providing oil of better nutritional and chemical quality. In the variability analysis, the accessions were clustered into five groups, which had different averages for SOP and fatty acid concentration of seed oil, an approach that will guide the use of appropriate germplasm in programs aimed at genetic breeding for SOP and seed oil profile. Per se analysis identified BGH-4610, BGH-5485A, BGH-6590, BGH-5556A, BGH-5472A, and BGH-5544A as the most promising accessions in terms of SOP, with an average (μ + g) of approximately 0.20 t ha^-1. The most promising accessions for a higher oleic acid concentration of seed oil were BGH-5456A, BGH-3333A, BGH-5361A, BGH-5472A, BGH-5544A, BGH-5453A, and BGH-1749, with an average (μ + g) of approximately 30%, almost all of which were also the most promising in terms of a lower linoleic acid concentration of the seed oil, with an average (μ + g) of approximately 45%. Part of the C. moschata accessions evaluated in the present study can serve as a promising resource in genetic breeding programs for SOP and fatty acid profile, aiming at the production of oil with better nutritional and physicochemical quality.