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  • Author or Editor: Mekhled Alenazi x
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The influence of storage temperature and length of time in storage on anthocyanin tuber concentration were investigated in seven potato genotypes. These genotypes were cultivars `All Blue' and `Yukon Gold' plus five selections that were various skin/flesh color types of red/red, purple/purple, white/yellow, and two red/yellow types. The red, blue, and purple colors are the result of various anthocyanin compounds. Tubers of the seven genotypes were stored at 4.4 or 10 °C for 0, 4, 6, 8, 10, 12, 16, 20, or 24 weeks. Both fresh and freeze-dried samples of the tubers were evaluated for each temperature and time treatment combination. Extractable anthocyanins were found in only the three pigmented genotypes red/red, purple/purple, and `All Blue'. Anthocyanin concentrations were estimated spectrophotometrically with a Molecular Devices Spectramax 384, based upon extinction coefficients reported in the literature for purple and red pigmented potatoes. Anthocyanin concentration increased in storage as time in storage increased for both fresh and freeze-dried samples. Tubers stored at the cooler temperature (4.4 °C) had higher levels of anthocyanin than those tubers stored at the higher temperature (10 °C). Increased levels of anthocyanins in cold-stored tubers may be linked to the conversion of starch to sugar (so called cold sweetening) known to occur at cold storage temperatures. Pigment extraction was more efficient from freeze-dried tuber samples compared to fresh tuber samples. There was, however, a similar increasing trend in both freeze-dried and fresh tuber sources with storage duration.

Free access

The present study reports on the effect of humic and salicylic acids on the growth, yield, and fruit quality of three red sweet pepper (Capsicum annuum) cultivars: Barbero, Ferrari, and Imperio. The plants were grown in a greenhouse and the leaves were treated with humic or salicylic acids at 0, 0.5, 1.0, and 1.5 g·L−1 at 20, 40, and 60 days after transplanting. Foliar application of humic or salicylic acids significantly increased vegetative growth, fruit yield, and quality of the three cultivars as compared with the control plants. However, salicylic acid treatment proved more effective than humic acid treatment. Red sweet pepper plants of all three cultivars sprayed with 1.5 g·L−1 salicylic acid showed the greatest vegetative growth; fruit yield components, such as fruit number, diameter, and fresh and dry weights; and fruit quality traits, such as vitamin C content, total soluble solid content, titratable acidity, and total sugar content, than the plants in all other treatments. There were significant differences (P ≤ 0.05) among cultivars in response to humic and salicylic acid foliar application; ‘Ferrari’ showed significantly higher yield and productivity than ‘Barbero’ or ‘Imperio’. ‘Ferrari’ plants sprayed with 1.5 g·L−1 salicylic acid showed the highest fruit weight (202.41 g) and flesh thickness (68 mm), both of which are preferred by consumers, and therefore, have increased market value. This treatment also increased total yield by 27.7% (16.03 t·ha−1), 15.9% (12.38 t·ha−1), and 17.9% (11.88 t·ha−1) in ‘Barbero’, ‘Ferrari’, and ‘Imperio’, respectively. Therefore, salicylic acid foliar application is recommended for enhancing fruit yield and quality of greenhouse-grown red sweet pepper.

Open Access

Red radish is a nutritious root vegetable crop that has a short production cycle. Water deficit limits plant productivity, affecting its quantity and quality. Compost amendment offers a potential solution to mitigate water deficit effects. This study assessed the impact of compost manure rates (0%, 50%, 75%, and 100%) and irrigation treatments (40%, 60%, 80%, and 100% of evapotranspiration) on ‘Crimson Giant’ red radish production. Significant differences in growth and quality were observed among these treatments. Compost rates of 75% and 100% improved leaf gas exchange, plant growth (leaf count, fresh weight, dry weight, and area; stem length), root development, total yield (root fresh weight, dry weight, diameter, and length), and root quality (vitamin C and total soluble solid and titratable acidity). The 100% compost and 100% irrigation combination achieved the highest yields. Under water deficit, applying 75% or 100% compost with 80% irrigation conserved 20% of water while maintaining radish output. Overall, compost amendment effectively enhanced red radish growth and production under water deficit.

Open Access