Germplasm of Brazilian winter squash (Cucurbita moschataD.) displays vast genetic variability, allowing identification of promising genotypes for agro-morphological traits

Abstract

13Winter squash fruits (Cucurbita moschata D.) are among the best sources of vitamin A 14 precursors and constitute sources of bioactive components such as phenolic compounds and 15 flavonoids. Approximately 70% of C. moschata seed oil is made up of unsaturated fatty acids, 16 with high levels of monounsaturated fatty acids and components such as vitamin E and 17 carotenoids, which represent a promising nutritional aspect in the production of this vegetable. 18C. moschata germplasm expresses high genetic variability, especially in Brazil. We assessed 91 19 C. moschata accessions, from different regions of Brazil, and maintained at the UFV Vegetable 20 Germplasm Bank, to identify early-flowering accessions with high levels of carotenoids in the 21 fruit pulp and high yields of seed and seed oil. Results showed that the accessions have high 22 variability in the number and mass of seeds per fruit, number of accumulated degree-days for 23 flowering, total carotenoid content, and fruit productivity, which allowed selection for 24 considerable gains in these characteristics. Analysis of the correlation between these 25 characteristics provided information that will assist in selection to improve this crop. Cluster 26 analysis resulted in the formation of 16 groups, confirming the variability of the accessions. Per 27 se analysis identified accessions BGH-6749, BGH-5639, and BGH-219 as those with the earliest 28flowering. Accessions BGH-5455A and BGH-5598A had the highest carotenoid content, with 29 averages greater than 170.00 μg g -1 of fresh mass. With a productivity of 0.13 t ha -1 , accessions 30 BGH-5485A, BGH-4610A, and BGH-5472A were the most promising for seed oil production. 31These last two accessions corresponded to those with higher seed productivity, averaging 0.58 2 32 and 0.54 t ha -1 , respectively. This study confirms the high potential of this germplasm for use in 33 breeding for promotion of earlier flowering and increase in total carotenoid content of the fruit 34 pulp and in seed and seed oil productivity. 35 36 38 39 3 65 making this crop fundamental for ensuring healthier diets and promoting food security in the 66 regions where it is grown, particularly in less developed regions and in the context of family-67 based farming. 68 Associated with its socio-economic importance, C. moschata germplasm commonly expresses 69 high genetic variability in all regions where it occurs [15, 16, 17], especially in Brazil [18, 19, 70 20]. Archaeological evidence indicates that this species was present in Latin America prior to 71 colonisation, and appears to have already been an important component in the diet of the native 72 peoples living there [21, 22, 23]. Currently, the variability of this vegetable in Brazil is closely 73 tied to the human populations involved in its cultivation, who are predominantly family-based 74 farmers. The selection practised over time by these populations, associated with the exchange of 75 seeds between them, and the natural occurrence of hybridization in the germplasm of th...