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Potassium (K) is a critical plant nutrient that determines quality in a myriad of crops and increases production yields. However, excessive application of various types of K fertilizers can decrease both the food quality and yields, which translates as economic losses and food safety issues. The objectives of this study were to 1) elucidate the impacts of different application rates of various K fertilizers on garlic, with the aim to identify the optimal and most economical K fertilizer dosage and 2) compare the effects of applying two common K fertilizers (KCl and K₂SO₄) on garlic, to determine the optimal combination. From 2018 to 2020, we utilized two distinct K-fertilized fields to conduct our experiments. The results revealed optimal KCl fertilization increased the biomass and vegetation index in garlic, and promoted the transfer of nitrogen, phosphorus, and potassium nutrients from the stem and leaf to bulb, thereby increasing bulb production. The application of KCl fertilizer increased the number of cloves, the diameters of the cloves and bulbs, and reduced variations in bulb size. In addition, the application of KCl fertilizer improved the nutritional quality (Vitamin C, soluble sugar, soluble protein, and allicin) of the garlic and reduced the accumulation of nitrate. However, excessive KCl fertilizer cause decreased yields, appearance traits, and nutritional quality. Applying the same rate of K fertilizer in the form of K₂SO₄ in isolation increased the garlic yield by only 0.1% to 22.5% when compared with KCl fertilizer. However, the results were not always significant. In this study, the highest yields, appearance traits, and nutritional quality were achieved with the ratio of K₂SO₄: KCl = 3:1. Consequently, to ensure the highest economic value (considering the market prices of K fertilizer, garlic sprouts, and bulbs), the authors recommend a K fertilizer rate of 252.5 kg·ha⁻¹ K₂O, with K₂SO₄ accounting for 61.6% for garlic production in field.

Impacts of drought stress on crop production can significantly impair farmer’s revenue, hence adversely impacting the gross national product growth. For cowpea [Vigna unguiculata (L.) Walp.], which is a legume of economic importance, effects of drought at early vegetative growth could lead to substantial yield losses. However, little has been done with respect to breeding for cowpea cultivars withstanding drought at early vegetative growth. In addition, previous investigations have focused on how plant morphology and root architecture can confer drought tolerance in cowpea, which is not sufficient in efforts to unravel unknown drought tolerance–related genetic mechanisms, potentially of great importance in breeding, and not pertaining to either plant morphology or root architecture. Therefore, the objective of this study was to evaluate aboveground drought-related traits of cowpea genotypes at seedling stage. A total of 30 cowpea genotypes were greenhouse grown within boxes and the experimental design was completely randomized with three replicates. Drought stress was imposed for 28 days. Data on a total of 17 aboveground-related traits were collected. Results showed the following: 1) a large variation in these traits was found among the genotypes; 2) more trifoliate wilt/chlorosis tolerance but more unifoliate wilt/chlorosis susceptible were observed; 3) delayed senescence was related to the ability of maintaining a balanced chlorophyll content in both unifoliate and trifoliate leaves; and 4) the genotypes PI293469, PI349674, and PI293568 were found to be slow wilting and drought tolerant. These results could contribute to advancing breeding programs for drought tolerance in cowpea.

Callus induction and plant regeneration play a key role in transgenic technology. Although much progress has been made with respect to eggplant, this type of research is insufficiently developed in Solanum torvum (a wild relative of eggplant), which contains a large number of resistance genes. Here, a high-efficiency regeneration system of S. torvum was established. Stem segments and leaves were cultured on Murashige and Skoog (MS) medium supplemented with 0.5–3.0 mg·L⁻¹ 6-benzyladenine (6-BA) and 0.1–0.6 mg·L⁻¹ α-naphthaleneacetic acid (NAA). The highest callus induction ratio (100%) was produced on MS + 1.0 mg·L⁻¹ 6-BA + 0.5 mg·L⁻¹ NAA. The combination of 0.5 mg·L⁻¹ BA and 1.0 mg·L⁻¹ 2,4-dichlorophenoxyacetic acid in MS medium (double microelement) was the best for plant regeneration. Well-developed shoots rooted on half-strength MS medium supplemented with 0.1 mg·L⁻¹ indole-3-acetic acid (IAA). These results will be helpful for functional verification of resistance genes from S. torvum and may be useful to those working in the field of eggplant breeding.

Previous investigations showed that accumulations of Na⁺ and Cl⁻ in leaves resulted in reductions in chlorophyll content, thereby affecting photosynthesis. Understanding how chlorophyll content evolves over time will help plant breeders to select cowpea genotypes with better tolerance to salinity by allowing them to choose those with more stable chlorophyll content under salt stress. The objective of this study was to assess how the chlorophyll content of cowpea genotypes changed over the course of 24 d of salt stress at the seedling stage. A total of 24 cowpea genotypes with different salt responses were used in this study. The experiment used a split-plot design with salt treatment as the main plot and cowpea genotypes as the subplot. In the main plot, there were two salt treatments: 0 mm (ionized water) and 200 mm NaCl. In the subplot, the cowpea genotypes were arranged as a completely randomized design with three replicates per genotype. The results revealed that: a1) the time × genotype interaction was significant under conditions with and without salt; 2) chlorophyll content slowly decreased in the salt-tolerant genotypes; 3) chlorophyll content slightly increased on day 6 and day 9 of salt stress in both moderate and sensitive genotypes, but it decreased at a faster rate than in the salt-tolerant genotypes; and 4) salt-sensitive genotypes were completely dead on day 24 of salt stress, whereas the salt-tolerant genotypes were able to maintain a significant amount of chlorophyll content. These results can be used to advance breeding programs for salt tolerance in cowpea.