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

Abstract

Winter squash fruits (Cucurbita moschata D.) are among the best sources of vitamin A precursors and constitute sources of bioactive components such as phenolic compounds and flavonoids. Approximately 70% of C. moschata seed oil is made up of unsaturated fatty acids, with high levels of monounsaturated fatty acids and components such as vitamin E and carotenoids, which represent a promising nutritional aspect in the production of this vegetable. C. moschata germplasm expresses high genetic variability, especially in Brazil. We assessed 91 C. moschata accessions, from different regions of Brazil, and maintained at the Federal University of Viçosa (UFV) Vegetable Germplasm Bank, to identify early-flowering accessions with high levels of carotenoids in the fruit pulp and high yields of seed and seed oil. Results showed that the accessions have high variability in the number and mass of seeds per fruit, number of accumulated degree-days for flowering, total carotenoid content, and fruit productivity, which allowed selection for considerable gains in these characteristics. Analysis of the correlation between these characteristics provided information that will assist in selection to improve this crop. Cluster analysis resulted in the formation of 16 groups, confirming the variability of the accessions. Per se analysis identified accessions BGH-6749, BGH-5639, and BGH-219 as those with the earliest flowering. Accessions BGH-5455A and BGH-5598A had the highest carotenoid content, with averages greater than 170.00 μg g-1 of fresh mass. With a productivity of 0.13 t ha-1 , accessions BGH-5485A, BGH-4610A, and BGH-5472A were the most promising for seed oil production. These last two accessions corresponded to those with higher seed productivity, averaging 0.58 and 0.54 t ha-1 , respectively. This study confirms the high potential of this germplasm for use in breeding for promotion of earlier flowering and increase in total content of fruit pulp carotenoids and in seed and seed oil productivity.

Population Structure and Genetic Diversity of Cucurbita moschata Based on Genome-Wide High-Quality SNPs

“…Many of the Cucurbita germplasms have been cultivated over generations from family-based farmers in many countries. The selection of these germplasms has been practiced over time by these populations, which is associated with the exchange of seeds between them, and the natural occurrence of the hybridization in the germplasm of this species has contributed to its increased variability [ 15 ].…”

“…In order to do this, we gathered a large number of germplasms that have a diverse origin from 42 countries and extracted the high quality 2071 SNPs throughout the 20 C. moschata chromosomes. It is a remarkable size of germplasm and genetic markers compared to the previous studies, in which only three morphological characters or 11 SSR markers that contained 122 alleles were used to assess the genetic diversity in Brazil or Mexico [ 6 , 15 ].…”

“…There have been few studies about the genetic diversity of wild C. moschata germplasm until now, but there are many studies on the domesticated Cucurbita germplasm available, especially with C. pepo [ 11 , 12 , 13 ]. Even in the cases of the analysis of wild germplasm, the accessions consisted of small sizes of germplasm or landraces only from specific regions or countries [ 6 , 14 , 15 ]. One of the most recent studies is about the genetic variability among 91 accessions from different regions of Brazil that used agro-morphological characteristics, such as seed related traits and carotenoids contents.…”

“…One of the most recent studies is about the genetic variability among 91 accessions from different regions of Brazil that used agro-morphological characteristics, such as seed related traits and carotenoids contents. They clustered the germplasm into 16 groups according to the phenotypic variance and suggested the promising accessions by the per se approach for the effective application to breeding programs [ 15 ]. Another study showed the genetic divergence according to the elevation gradient in Mexico.…”

Research Article Genetic control of internode length in winter squash (<i>Cucurbita</i> <i>moschata</i>)

“…Currently, the pulp of C. moschata fruits is the most important part of this vegetable used as food and is used in various ways in human nutrition. The pulp of its fruits is one of the most promising sources of carotenoids, such as β-carotene, a precursor of pro-vitamin A (Rodriguez-Amaya et al, 2008, Carvalho et al, 2012Gomes et al, 2020).…”