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Most of the tomato (Solanum lycopersicum) varieties currently used in organic farming were bred for conventional farming, often characterized by high-input use. These varieties do not perform as well in low-input organic systems, generating the need to develop varieties that are adapted to organic management systems. This project focused on improving flavor, disease resistance, and yield, all identified as key traits by organic tomato farmers in the Upper Midwest, USA. Ten advanced tomato breeding lines and two check varieties were developed and evaluated for 16 traits in organic high tunnel systems in 2020 and 2021. The line CSDE-F6.47 averaged 6.32 kg/plant and obtained high flavor intensity and overall flavor scores (3.78 and 3.69 out of 5, respectively). The line JBDE-F5.31 was another outstanding line, with a yield of 5.18 kg/plant, with good flavor intensity (3.32) and overall flavor (2.92) scores. Broad-sense heritability of marketable weight per plant was high (0.91), and the genetic variance was also high, which shows the opportunity to continue to increase the marketable weight in lines with excellent flavor. A significant positive correlation was found between overall flavor and °Brix (0.56), and titratable acidity (0.70), indicating that both measurements can be good predictors of overall flavor. The most promising lines will be further evaluated on-farm to evaluate their potential as releasable varieties.
Improving the productivity of sweet pepper (Capsicum annuum) is essential to meeting the increasing global demand. This can be partially accomplished by investigating and determining high-yield traits, thereby enabling the selection or breeding of high-yield plants. Therefore, this study aimed to determine the high-yield traits of sweet pepper by analyzing its yield components. We analyzed yield components of commercially available cultivars (red and yellow) that were hydroponically grown in a greenhouse (e.g., total fruit fresh weight, fruit dry weight, fruit dry matter content, total dry matter production, and light-use efficiency) using Pearson’s correlation coefficient (r). Our results showed the following: the total fruit fresh weight was positively and negatively correlated with the fruit dry weight (r = 0.83; P < 0.001) and fruit dry matter content (r = –0.70; P < 0.001), respectively; the fruit dry weight was positively correlated with the total dry matter production (r = 0.50; P < 0.01), and the total dry matter production was positively correlated with the light-use efficiency (r = 0.93; P < 0.001); and the cultivars with the high total fruit fresh weight were characterized by the notably low fruit dry matter content and high light-use efficiency (e.g., ‘Gialte’). In conclusion, high-yielding sweet peppers are characterized by a low fruit dry matter content and high light-use efficiency.
Macrophomina phaseolina, the causal agent of charcoal rot, is one of the most destructive soil-borne pathogens that affect the global strawberry industry. Resistant cultivars are critical for ensuring the profitability of strawberry production without the protection historically provided by methyl bromide. Previously, three loci, namely, FaRMp1, FaRMp2, and FaRMp3, associated with quantitative resistance to Macrophomina phaseolina have been identified and validated across diverse populations and environments. Among those, the locus with the largest effect, FaRMp3, was initially detected in crosses with an exotic Fragaria ×ananassa selection. We introgressed the favorable FaRMp3 allele into elite germplasm in the University of Florida strawberry breeding program already segregating for FaRMp1 and FaRMp2 and confirmed its phenotypic effects across various genetic backgrounds. Subsequently, we developed a high-throughput genotyping assay to facilitate the transfer and selection of FaRMp3 in breeding populations via marker-assisted selection. Given that three quantitative trait loci (QTL) contribute to partial resistance to Macrophomina phaseolina, stacking them within a single genotype presents a potential strategy for enhancing resistance. We screened 564 individuals that segregate for favorable alleles at all three QTL to assess their effects singly and in combination across multiple genetic backgrounds and production seasons. Inoculated field trials revealed that the three QTL cumulatively enhanced resistance levels, and that two-way QTL combinations including FaRMp3 provide increased protection against the pathogen. Pyramiding all three loci achieved the strongest resistance and could provide substantial economic value to the strawberry industry.
Strawberry fruits are popular among consumers because of their unique flavor and reported health benefits. However, microbial growth and oxidative stress that occur in postharvest storage cause strawberry fruits to have a relatively short postharvest life, which reduces consumer acceptance. This study aimed to evaluate the effects of exogenous melatonin application on the enzymatic activity and postharvest quality of strawberry fruits that are stored at 4 ± 0.5 °C. A total of 288 fruits with four replicates for each of the three treatments (control, 200 μM melatonin, and 500 μM melatonin) were used. Several quality metrics were regularly assessed at 3-day intervals during the 18-day storage trials. The results suggested that the exogenous melatonin application significantly increased the activity of antioxidant enzymes at the physiological level, including catalase, ascorbate peroxidase, superoxide dismutase, and peroxidase which led to reductions in weight loss, the decay incidence, and the malondialdehyde level. The use of melatonin successfully delayed changes in the soluble solids concentration, ascorbic acid, titratable acidity, and fruit firmness. The results indicated that applying 500 μM melatonin to strawberries would be a useful strategy for increasing their shelf life.
The western portion of the Pacific Northwest is known for being dry in the summer and cool and humid in the other months. Tall fescue is valued for its drought and heat tolerance, making it a desirable choice in regions where water is scarce and often restricted by legislation during periods of drought in the summer. However, cool and humid climates make it challenging to manage tall fescue in the winter because unacceptable quality is often observed due to low-temperature diseases and thinning in turf. A field trial was initiated in Autumn 2020 in Corvallis, OR, USA to assess the effects of mowing height as well as fertility timing and rate on tall fescue performance. Two mowing heights of 5.1 and 7.6 cm, four seasonal fertility timings, and three levels of annual N rates of 98, 196, and 294 kg·ha−1·yr−1 were evaluated using a 2 × 4 × 3 factorial experiment in a strip-plot design. Quantitative data of percent green cover and normalized difference vegetation index (NDVI) suggest that autumn fertilization is needed in cool, humid areas where tall fescue is actively growing in the winter months. The annual fertilization rate of 294 kg·ha−1·yr−1 N produced higher green turf cover and NDVI, compared with 98 or 196 kg·ha−1·yr−1 N. Furthermore, divergent effects of mowing heights were observed during winter compared with other months, suggesting that tall fescue could be mowed lower at 5.1 cm during cool, humid winter months and higher at 7.6 cm in other seasons for better overall turfgrass growth and less winter disease and thinning. Our research provides practical cultural practices for managing tall fescue turf in the Pacific Northwest or similar climates.
Purple paprika (Capsicum annuum) is a vegetable with potential economic value; however, enhancing and maintaining the purple fruit color is challenging. We investigated the effects of night blue-light supplementation on fruit growth, anthocyanin content, and gene expression in purple paprika. During two duplicated experiments conducted in spring and autumn, purple paprika plants were subjected to blue-light supplementation at night. Ten days after fruits were pollinated, night blue light with photosynthetic photon flux density (PPFD) of 80 to 100 µmol·s−1·m−2 was supplied from 1800 HR to 0500 HR (11 hours). Fruit samples were harvested 15, 20, and 40 days after pollination from control (no-light treatment) and blue light–treated fruits. The fruit size, fresh weight, anthocyanin content, and expression levels of anthocyanin biosynthesis-related genes (HY5, bHLH, WDR, MYB, PAL, CHS, F3H, DFR, ANS, and UFGT) were determined. Blue-light supplementation increased the anthocyanin-related gene expressions in the fruit peel, enhancing anthocyanin synthesis and accumulation. However, there were no significant differences between the growth of control and blue light–treated fruits. These findings highlight the potential of night blue-light supplementation to enhance anthocyanin content in purple paprika fruits without affecting overall fruit growth.