IDENTIFICATION OF HIGH SEED OIL YIELD AND HIGH OLEIC ACID CONTENT IN BRAZILIAN GERMPLASM OF WINTER SQUASH (Cucurbita moschata D.)

Abstract

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 carotenoid, constituting a promising food in nutritional terms. Associated to this, the Brazilian germplasm of C. moschata exhibits remarkable variability, representing an important source for the genetic breeding of this vegetable and other cucurbits. In this context, the present study evaluated the productivity and profile of the seed oil of 91 C. moschata accessions from different regions of Brazil and maintained in the Vegetable Germplasm Bank of the Federal University of Vicosa (BGH-UFV). A field experiment was conducted between January and July 2016. The tested C. moschata accessions showed high genetic variability in terms of characteristics related to seed oil productivity (SOP), such as the mass 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, greater SOP can be achieved while maintaining high oleic acid content and low linoleic acid content, providing oil of better nutritional and chemical quality. In variability analysis, the accessions were clustered into five groups, which presented different averages for SOP and fatty acid content of seed oil; 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 average (+g) of approximately 0.20 t ha-1. The most promising accessions for higher oleic acid content of seed oil were BGH-5456A, BGH-3333A, BGH-5361A, BGH-5472A, BGH-5544A, BGH-5453A, and BGH-1749, with average (+g) of approximately 30%, and almost all of these accessions were also the most promising in terms of lower linoleic acid content of seed oil, with average (+g) of approximately 45%. Overall, 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.