The Formation of Fruit Quality in Cucumis sativus L

Genetic diversity, morphological traits, quality traits and antioxidants potentiality of Coccinia grandis germplasm under rainfed semi-arid region

The present study was conducted to evaluate the genetic variability for morphological and qualitative traits of Coccinia for development of trait specific lines at ICAR-Central Horticultural Experiment Station (CIAH-RS), Panchmahals (Godhra), Gujarat during 2020-2022. In this study, we evaluated 26 gynoecious accessions to assess the genetic divergence through principal component and cluster analysis. The experiment was carried out in a randomized complete block design with three replications under rainfed semi-arid conditions. High values of PCV and GCV were observed for variables such as NFFP (25.13 and 22.20), PL (23.14 and 20.69), FD (24.01 and 21.46), AFW (22.98 and 20.13), NFPY (26.38 and 24.40), FYP (37.57 and 31.29), FY (35.55 and 33.20), AsC (28.65 and 27.73), Ac (24.32 and 21.06), TSS (37.23 and 35.94), DPPHL (20.71 and 20.38), FRAPL (21.08 and 20.92), TPF(20.81 and 20.45) respectively. High heritability coupled with high genetic advance as per cent of mean was observed for vine length (VL), internodal length (IL), number of female flowers per plant (NFFP), fruit length (FL), peduncle length (PL), fruit diameter (FD), average fruit weight (AFW), number of fruit per plant per year (NFPY), fruit yield per plant (FYP), fruit yield (FY), ascorbic acid (AsC), acidity (Ac), total soluble solids (TSS), total phenols in leaves TPL), total flavonoids in leaves TFL, CUPRAC in leaves (CUPRACL), DPPH in leaves (DPPHL), FRAP in leaves (FRAPL), Total phenols in fruits (TPF), Total flavonoids in fruits (TFF), CUPRAC in fruits (CUPRACF) and DPPH in fruits (DPPHF). The FYP exhibited a significant positive correlation with variables like VL (0.6833), IL (0.2991), NFFP (0.8107), FD (0.5245), AFW (0.6766), NFPY (0.7659), ASC (0.4611), TSS (0.5004) and TPF (0.4281). The estimates of genetic parameters revealed scope for further improvement of fruit yield by selection. Of the eight principal components, PC-I through PC-VIII had eigen values greater than 1 and it accounts 85.02% of the total variation for 26 gynoecious accessions of Ivy gourd. The eigen values of PC-I comprised 5.775% of total variation followed by PC-II (4.250%), PC-III (3.175%), PC-IV (2.588%), PC-V (1.828%), PC-VI (1.447%), PC-VII (1.179%) and PC-VIII (1.013%).The cluster VI and cluster I having highest mean values for most of traits under study. Thus, genotypes from the distinct cluster like cluster VI and I for should be used for selection of parents and varietal improvement for further breeding programme in ivy gourd.

Non-targeted metabolomic analysis for the comparative evaluation of volatile organic compounds in 20 globally representative cucumber lines

Volatile organic compounds (VOCs) are one of the main fruit-quality determinants in cucumber. Here, we investigated the differences in the VOC and primary metabolite composition among 20 representative cucumber lines. Results of non-targeted metabolomics revealed that the cucumber breeding line of the Korean group showed a unique VOC composition in the fruit peel compared to the other groups. Fruit-flesh VOCs significantly differed among Korean, European, and Thai fruits. The main cucumber flavor components, 2-hexenal, hexanal, 6-nonenal, 2,4-nonadienal, and 2,6-nonadienal, were lower in the Korean cucumber lines than in the others. Conversely, linoleic acid derivatives and α-linolenic acid, which are precursors of these VOCs, were abundant in Korean cucumber line. This suggests that the metabolism related to the characteristic flavor of cucumber are downregulated in Korean cucumber line. This study provides novel insights into the fruit flavor-associated metabolome in various cucumber lines.

Characterization of Differences in the Composition and Content of Volatile Compounds in Cucumber Fruit

The cucumber is characterized by the presence of a wide range of volatile organic compounds (VOCs), which are recognized as the main responsible for its unique flavor. However, research on the types and contents of VOCs in different cucumber cultivars remains fragmentary. Here, using an automatic headspace solid-phase microextraction coupled with the gas chromatography-mass spectrometry method, the VOCs were analyzed in three representative cucumber cultivars, including YX, KX, and GX, with the best, middle, and worst flavor quality, respectively, which were selected from 30 cultivars after flavor quality evaluation. Principal component analysis revealed that the six biological replicates were grouped, indicating high reliability of the data. A total of 163 VOCs were detected. There were 28 differential VOCs in YX compared to GX, 33 differential VOCs in YX compared to KX, and 10 differential VOCs in KX compared to GX. Furthermore, K-means clustering analysis showed that 38 of the 43 no-overlapping differential VOCs were represented by the most abundant compounds detected in YX. The prevailing VOCs in YX included: hydrocarbons, aldehydes, and ketones. The data obtained in the present study extend our understanding the impact of cultivars on VOCs in cucumber and will help facilitate targeted breeding.

Advances in Understanding and Harnessing the Molecular Regulatory Mechanisms of Vegetable Quality

The quality of vegetables is facing new demands in terms of diversity and nutritional health. Given the improvements in living standards and the quality of consumed products, consumers are looking for vegetable products that maintain their nutrition, taste, and visual qualities. These requirements are directing scientists to focus on vegetable quality in breeding research. Thus, in recent years, research on vegetable quality has been widely carried out, and many applications have been developed via gene manipulation. In general, vegetable quality traits can be divided into three parts. First, commodity quality, which is most related to the commerciality of plants, refers to the appearance of the product. The second is flavor quality, which usually represents the texture and flavor of vegetables. Third, nutritional quality mainly refers to the contents of nutrients and health ingredients such as soluble solids (sugar), vitamin C, and minerals needed by humans. With biotechnological development, researchers can use gene manipulation technologies, such as molecular markers, transgenes and gene editing to improve the quality of vegetables. This review attempts to summarize recent studies on major vegetable crops species, with Brassicaceae, Solanaceae, and Cucurbitaceae as examples, to analyze the present situation of vegetable quality with the development of modern agriculture.