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Sulfur (S) is the fourth most essential nutrient after nitrogen (N), phosphorus (P), and potassium (K) with a direct role in amino acid syntheses, such as methionine, cysteine, and N assimilation. Potato is a fast-growing vegetable crop with a small crop cycle; therefore, nutrient applications at the appropriate time, place, rate, and source are essential. The objective was to determine the effect of different S sources on the potato tuber yield, specific gravity, external tuber quality, and internal tuber quality. This study was conducted in 2021 and 2022, and three S sources were applied at two different rates (T1, 45 kg⋅ha−1; T2, 90 kg⋅ha−1) using a 3 × 2 factorial design. Three S sources were derived from the sulfate of ammonia (AS; SO4 2− source), magnesium sulfate (EPTOP; S0 source), and gypsum (SO4 2− source). Three potato cultivars were used for this study (Atlantic, Satina, and Red La Soda). The total and marketable yields indicated a positive response to the application of the S sources. Gypsum and EPTOP outperformed AS, and the lower rate (T1) performed better than the higher rate (T2). In one of the trials, the maximum yield difference between AS and gypsum was 33%. The maximum specific gravity for cultivar Atlantic was found with AS and gypsum, whereas Red La Soda and Satina did not respond to any S source. We did not report the treatment effects on the external and internal disorders when weather affected them.
Cover cropping has been strongly promoted, but few growers have realized the benefits of this practice due to challenges linked to economic returns and whole-system management. In the western United States, winter legumes including faba bean have the potential to add economic value while offering soil health benefits compared with fallow fields. This experiment assessed the potential of five vegetable faba bean varieties for fresh pod yield, fresh pod quality, and biomass N return under a single and multiple pod harvest scheme. Vegetable faba bean varieties were further compared with two popular cover crop faba bean varieties, ‘Bell bean’ and ‘Sweet Lorane’ for cover crop and biomass N return benefits. The experiment revealed significant (P ≤ 0.05) genotypic variation for vegetable fresh pod yield, dry biomass, fresh pod quality, pod N removal, biomass N return, and C:N in three testing environments under the single and multiple harvest schemes. Finally, the vegetable variety ‘Vroma’ produced high average fresh pod yield under the single (16,178 kg·ha−1) and multiple (38,928 kg·ha−1) harvest schemes while maintaining high biomass N return under the single (119 kg·ha−1 N) and multiple harvests (97 kg·ha−1 N) compared with the cover crop varieties (128 kg·ha−1 N). This experiment demonstrated that a single fresh pod harvest on an early and high yielding faba bean variety can generate economic returns while also providing cover crop benefits that are comparable to termination of a faba bean cover crop on the same date.
Oakleaf hydrangea (Hydrangea quercifolia) is an understory shrub native to the southeastern United States. The species occupies a relatively small native range, and little is known about its demography, genetic diversity, or needs for conservation. Samples were collected from 188 plants in 73 locations throughout the species range and were genotyped using genotyping by sequencing. A structure analysis identified six genetic clusters that are geographically defined. Although these clusters are weakly differentiated, each has unique alleles. An environmental association analysis revealed that environmental variables explain 11.3% of genetic diversity, and population structure explains 13.5%. Further, 231 putative adaptive alleles were identified, most of which are correlated with precipitation-related variables, indicating that precipitation has an impact on genetic diversity in H. quercifolia. Many historically documented populations were found to be either extirpated or at risk of extirpation. The genetic clusters on the southern extent of the species range are relatively small and contain putative adaptive alleles at relatively high frequencies. These results highlight the importance of preserving representative germplasm from throughout the species range.
Recirculating nutrient solutions were treated using dimensionally stable anode (DSA)-based regenerative in situ electrochemical hypochlorination (RisEHc) in a deep water culture hydroponic lettuce (Lactuca sativa) production system. Phytotoxic effects were noted and attributed to the formation of chloramines in treated nutrient solutions containing ammonium. The presence of chloramines resulted in a decrease in overhead biomass by 53% using 2.27 mA/cm2 and 83% with 4.55 mA/cm2. Adding ultraviolet light as a tertiary treatment stage allowed the photodecomposition of chloramines, which prevented phytotoxicity in crops and caused no significant differences in growth between treatments. Furthermore, using a nitrate-based fertilizer also served to prevent phytotoxic effects in crops and showed no significant differences in growth between the control and 4.55 mA/cm2. In addition, it was found that the electrochemical flow cell (EFC) treatment resulted in a 13% increase in shoot biomass using 2.27 mA/cm2. The study demonstrated that phytotoxic effects can be prevented with the use of regenerative in situ hypochlorination through proper management and monitoring techniques in recirculating hydroponic systems.
The ability of a substrate component (organic or inorganic) to capture and retain water (hydration and wettability) is important to investigate and promote water-use–efficient practices. Many factors may play a role in the wettability of the material, including the processing of the material and its initial handling. The goal of this experiment was to determine the effect of moisture content (MC) on the sorptive behavior of substrates after an initial and secondary hydration cycle. Coir, peat, and aged pine bark were evaluated at a 33%, 50%, and 66% MC by weight. At all moisture levels, coir and bark were minimally affected by MC or the initial hydration cycle. Peat was the most vulnerable to changes in sorptive behavior as a result of wetting and drying cycles. After a wetting and drying cycle, the maximum volumetric water content of peat from surface irrigation was reduced 21.5% (volumetrically), more than three times any other treatment. The hydration efficiency of peat was improved when blended with as little as 15% coir. These experiments provide evidence that MC and initial handling of the substrate can lead to differences in initial water use efficiency.
Simple sequence repeat (SSR) markers were used to authenticate ramets of 11 Persian walnut (Juglans regia L.) varieties. All varieties and 28 of their ramets (n = 39) were genotyped with 17 SSR markers. The genetic profiles revealed two off-types: the ramets Serr 4 (S4) and Vina 1 (V1). SSR fingerprints individuating 11 walnut varieties were possible using 13 polymorphic SSRs that could be used in the future to identify clones of these varieties. Except for ‘Chandler’, each cultivar could be distinguished using a combination of two SSR loci. This result emphasizes the efficacy of the SSR markers in true-to-type validation of walnut orchards.
Ten 16-year-old trees were used as test materials to investigate the effect of foliar calcium fertilizer on the sugar content of ‘Feizixiao’ litchi (Litchi chinensis Sonn.) pulp. The experiment began 35 days after anthesis (DAA) in 2020 and 2021, and the treatment was a foliar spray application of 0.3% CaCl2 aqueous solution, whereas the control was a foliar spray application of water. The sugar content, sucrose-metabolizing enzymes, and ATP-dependent phosphofructokinase (PFK) activities in pulp were measured in 2020 and 2021. Transcriptome sequencing (RNA-seq) was performed on RNA samples from treatment and control fruit pulps at 35, 63, and 69 DAA (full mature stage) in 2020, and 10 genes were chosen for confirmation by real-time polymerase chain reaction (PCR) in 2020 and 2021. At full maturity, the soluble sugar content in the calcium-treated group was extremely significantly or significantly higher than that in the control group. After 63 DAA, the net sucrose-metabolizing enzyme activity in the calcium-treated group was significantly higher than that in the control group. Furthermore, at full maturity, the calcium-treated group had significantly higher sucrose synthase cleavage activity and significantly lower PFK activity than the control group. Fifty-four highly expressed genes in the glycolytic pathway (EMP) were screened from transcriptome data, including hexokinase, PFK, and pyruvate kinase genes; 87% of these genes were downregulated in the treatment group compared with the control group at 69 DAA in 2020. The linear regression between RNA-seq and real-time PCR results was significant in 2020 (r = 0.9292) and 2021 (r = 0.8889). When the fruit is fully ripe, calcium treatment increases net sucrose-metabolizing enzyme activity by increasing sucrose synthase cleavage activity, promoting the accumulation of reducing sugars, and it downregulates phosphofructokinase gene expression in EMP, promoting sugar accumulation.