Application methods of biostimulants affect the production and postharvest conservation of yellow melon

Worldwide, Brazil holds the fifth position in melon fruits exportation, further expanding its products to provide for the growing demand. This expansion is the result of the development and application of new technologies, including the management of the use of biostimulants. However, for melon crops, the information in the literature on the use of biostimulants remains limited to the effects of different doses on fruit quality at the time of harvest. Therefore, this study aimed to evaluate the influence of different methods of pre-harvest application of two biostimulants on the production and postharvest conservation of fruits of yellow melon cv. Iracema. The treatments consisted of a combination of three factors: two plant biostimulants (Crop Set® and Spray Dunger®), two application methods of the products (fertigation and spraying), and five times of postharvest storage (0, 14, 21, 28 and 35 days). An additional control treatment corresponded to plants without biostimulant application. The fruits were evaluated for production and physicochemical attributes: average mass, yield, flesh firmness, titratable acidity, soluble solids content, SSC/TA ratio, pH, total soluble sugars, and weight loss. Fertigation is the recommended application method of biostimulants for yellow melon due to its effect on the increase of average mass, yield, flesh firmness, soluble solids content, and total soluble sugars of the fruits in relation to the spraying method.

Fresh haskap berry postharvest quality characteristics and storage life

Haskap (Lonicera caerulea L.) is a relatively new berry crop in North America, and little research exists regarding its postharvest storage characteristics or storage life. Postharvest changes in berry quality, and principal factors limiting storage life at 1.1 °C and 95% relative humidity, were evaluated up to 14 days for three cultivars in 2019 and up to 28 days for six cultivars in 2020. Containerized berries were periodically assessed for soluble solids content (SSC), skin rupture force (SRF) (both 2019 and 2020) and flesh firmness, titratable acidity (TA), and Brix/acid ratio (B/A) (2020 only). External appearance was also evaluated both years, revealing berry shrivel as the primary factor negatively impacting visual appeal, followed distantly by low incidence of spoilage later in storage. All cultivars exhibited relatively constant postharvest SSC and decreasing SRF, flesh firmness, and TA (resulting in increasing B/A ratio). Postharvest quality differed slightly between years; relative SRF was consistent among cultivars while SSC was not. Some cultivars had a portion of shriveled berries at harvest, pointing to a need for cultivar-specific harvest indices. Mean days to slight shrivel for individual berries varied among cultivars evaluated, ranging from 7.5–21.9 d postharvest, with mean weight loss ranging from 1.2%–1.6% at this stage. Combined with group marketability estimates — set at a threshold of 10% severely shriveled berries — we estimate a storage life of 7–10 d for fresh haskaps. Additional research is needed to delineate maturation physiology and optimize harvest timing.

Effects of mode and timing of calcium chloride application on tissue calcium concentration and acceptability of mango fruits

Mango (Mangifera indica L) production in Kenya directly supports approximately 200,000 farmers and many other beneficiaries. Despite this, its production suffers from post-harvest losses due to the fruits' short shelf life in ambient conditions. Calcium maintains cell integrity, strengthens the cell wall, membrane structure, and thus increases shelf life. A completely randomized block design with a split plot arrangement was used to compare the effect of spraying and immersion of ‘Van Dyke' mango fruits at maturity or 15 days later in calcium chloride at different concentrations (0.5%, 1%, 1.5%, or 0%) and times on the fruit ripening rate and organoleptic acceptance. The peel firmness (N), total soluble solids (0Brix), flesh color (Ho), beta carotene (mg/100ml), and carbon dioxide evolution (ml/kg/hr) of fruits were determined at time 0 and every two days for up to eight days in ambient conditions. Additionally, organoleptic characteristics, flesh firmness, calcium concentration (g/mg), and their correlations were determined. Fruits immersed in calcium chloride at maturity had higher retained peel firmness (10.6 N, 10.3 N), deeper flesh color (37.45, 36.78), lower total soluble solids (14, 13.8), a lower carbon dioxide evolution (30.7 ml/kg/hr), higher beta carotene and higher flesh calcium concentration than fruits exposed to other treatments. Fruits sprayed at maturity outperformed those sprayed 15 days later in the studied parameters. Flesh calcium content correlated positively with flesh firmness (r= 0.913, r= 0.852), flesh color (r= 0.828, r= 0.841), fruit aroma (r=0.8199, r=0.841), and negatively with skin shriveling (r=-0.778, r=-0.806) and fruit flavor (r=-0.811, r=-0.829). Flesh firmness correlated negatively with skin shriveling (r=-0.868, r=-0.788) and fruit flavor (r=-0.8869, r=-0.821), but positively with peel color (r=0.9115, r=0.856) and aroma (r=0.907, r=0.848). Skin shriveling was found to have a negative relationship with peel color (r=-0.944, r=-0.93) and aroma (r=-0.944, r=-0.938), but a positive relationship with fruit flavor (r=0.933, r=0.947). Peel color correlated positively with aroma (r=0.979, r=0.977) and negatively with fruit flavor (r=-0.962, r=-0.950), respectively. Despite the effectiveness of post-harvest calcium chloride immersion in extending fruit shelf life, optimal use is advised to avoid deteriorated pulp flavor and increased shriveling. More research is needed to determine how calcium chloride can be made available to the fruit while it is still attached to the tree.

Multivariate Selection Index of Acerola Genotypes for Fresh Consumption Based on Fruit Physicochemical Attributes

Acerola (Malpighia emarginata DC.) is one of the most important fruit produced in the São Francisco Valley, a Semi-arid region in the Northeast of Brazil. This study aimed to evaluate the physicochemical quality of thirty-five acerola genotypes produced during two growing seasons in a Semi-arid region and to identify the best ones with potential for fresh consumption based on a multivariate selection index. Fruit of each genotype were harvested during two growing seasons at the maturity stage red-ripe, characterized by full red skin color. After harvest, the fruit were evaluated for diameter, mass, flesh firmness, soluble solids (SS), titratable acidity (TA), SS/TA ratio, ascorbic acid content and skin color. A multivariate selection index (SI) was applied for scoring and ranking the genotypes for fresh consumption based on red-ripe fruit physicochemical quality. According to the results, all physicochemical attributes had high variability among genotypes. The SI was a powerful tool for identifying genotypes with high potential for fresh consumption, since it allowed selecting genotypes with multiple desirable traits. In the first and second growing seasons, the SI identified the genotypes PROG 052 (SI = 76.1 and 78.9), BRS Rubra (SI = 74.1 and 99.5), Cabocla (SI = 72.3 and 70.7), Costa Rica (SI = 61.2 and 73.8) and PROG 069 (SI = 68.1 and 72.4) as the most promising ones for fresh consumption due to the presence of multiple desirable traits such as high diameter, mass, flesh firmness, SS, and SS/AT ratio, as well as lower acidity.

Identification of Key Gene Networks Associated With Cell Wall Components Leading to Flesh Firmness in Watermelon

Flesh firmness of watermelon is an important quality trait for commercial fruit values, including fruit storability, transportability, and shelf life. To date, knowledge of the gene networks underlying this trait is still limited. Herein, we used weighted genes co-expression network analysis (WGCNA) based on correlation and the association of phenotypic data (cell wall contents) with significantly differentially expressed genes between two materials, a near isogeneic line “HWF” (with high average flesh firmness) and inbred line “203Z” (with low average flesh firmness), to identify the gene networks responsible for changes in fruit flesh firmness. We identified three gene modules harboring 354 genes; these gene modules demonstrated significant correlation with water-soluble pectin, cellulose, hemicellulose, and protopectin. Based on intramodular significance, eight genes involved in cell wall biosynthesis and ethylene pathway are identified as hub genes within these modules. Among these genes, two genes, Cla012351 (Cellulose synthase) and Cla004251 (Pectinesterase), were significantly correlated with cellulose (r2 = 0.83) and protopectin (r2 = 0.81); three genes, Cla004120 (ERF1), Cla009966 (Cellulose synthase), and Cla006648 (Galactosyltransferase), had a significant correlation with water-soluble pectin (r2 = 0.91), cellulose (r2 = 0.9), and protopectin (r2 = 0.92); and three genes, Cla007092 (ERF2a), Cla004119 (probable glycosyltransferase), and Cla018816 (Xyloglucan endotransglucosylase/hydrolase), were correlated with hemicellulose (r2 = 0.85), cellulose (r2 = 0.8), and protopectin (r2 = 0.8). This study generated important insights of biosynthesis of a cell wall structure and ethylene signaling transduction pathway, the mechanism controlling the flesh firmness changes in watermelon, which provide a significant source to accelerate future functional analysis in watermelon to facilitate crop improvement.

Quantitative trait locus analysis of cucumber fruit texture using double-digest restriction-site-associated DNA sequencing

Fruit firmness and crispness are important traits of cucumber because they directly affect its commercial value. We performed quantitative trait locus (QTL) analysis of these fruit texture traits with the double-digest restriction-site-associated DNA sequencing (ddRAD-Seq) technique and detected 31 QTLs for fruit firmness: 11 for placenta firmness, 12 for skin firmness, and 8 for flesh firmness; and 25 QTLs for crispness-related scores: 10 for flesh crispness index, 8 for flesh apparent fractal dimension by Richardson plot, and 7 for flesh apparent fractal dimension by box-counting (Kolmogorov’s dimension). Several QTLs associated with flesh firmness and crispness are located near regions for fruit length, diameter, and length-to-diameter ratio, and for resistance to powdery mildew and downy mildew, indicating that gene linkage is likely to limit breeding efficiency. Our results will contribute to the development of informative DNA markers closely linked to genes for desirable fruit texture traits that are required for effective selection of new cultivars.

Önemli Çilek Genotiplerinin Tat Parametreleri Bakımından Değerlendirilmesi

Strawberry is an important fruit species whose production is increasing in the world and in our country due to its unique taste and aroma. It is known that the yield, taste and other important quality components of strawberry fruits are affected by the genetic structure as in many fruit species. In this context, a large amount of strawberry varieties have been developed as a result of strawberry breeding studies in the world. Similarly, breeding studies have been carried out at different intensities for many years at Çukurova University. In this study, the genotypes coded ‘33’, ‘36’ and ‘61’, which have become prominent as a result of the strawberry breeding program in our department, and commercial varieties such as ‘Fortuna’, ‘Rubygem’ and ‘Festival’, which are widely cultivated in the Mediterranean region, were compared in term of the properties such as soluble solids content (SSC), pH, fruit acid content and firmness during the extensive harvest period (January-May). As a result of the study, small amount of production was obtained in Mediterranean climatic conditions, and the highest SSC and flesh firmness values were obtained in the varieties and genotypes analysed in January. In terms of genotypes; the ‘36’ coded attracted attention with its relatively low acid content, as well as being higher than others with its SSC values varying between 8.0% and 13.1% throughout the season. Despite the strength of this genotype in terms of taste, it was found to be quite soft compared to commercial varieties (1.10-1.20 lb/inch2) with flesh firmness of 0.63 lb/inch2. It is thought that it is not possible to obtain the best quality variety in all aspects due to physiological and genetic reasons. However, strawberry breeders should aim to develop strawberry varieties that consist the characteristics at the highest levels in line with the fundamental goals they set.