Dolores Ledesma

Fruit quality and bioactive compounds with antioxidant activity of tomatoes grown on-farm: comparison of organic and conventional management systems.

Replicated field trials at three matched farm pairs in southern and central Taiwan were established in October 2004 and 2005 to compare fruit quality and nutritional parameters of tomatoes grown on-farm under organic versus conventional management systems in tropical and subtropical environments. Two processing tomato varieties were evaluated using a randomized complete block design at each of the farms. Aggregation of farms by type (organic vs conventional) across two years resulted in no significant differences between organic and conventional farming systems for all tomato fruit parameters measured, including quality (pH, soluble solids, acidity, and color), content of bioactive compounds with antioxidant activity (beta-carotene, lycopene, ascorbic acid, and total phenolics), and antioxidant activity. This study indicated no consistent effect of the farming system on tomato fruit parameters. Farm management skills combined with site-specific effects contributed to high lycopene levels, and the choice of variety significantly influenced the content of bioactive compounds, particularly ascorbic acid and total phenolics.

Variation for antioxidant activity and antioxidants in a subset of AVRDC—the World Vegetable Center Capsicum core collection

Pepper ( Capsicum sp.) is important in human diets in many parts of the world and a major source of several antioxidants, including carotenoids, ascorbic acid, tocopherols and phenolics. More information on genetic diversity within Capsicum for antioxidant (AO) content and antioxidant activity (AOA) could contribute to improved human health. We evaluated 46 Capsicum accessions from AVRDC—the World Vegetable Center Capsicum core collection for content of nine AO (five carotenoids, ascorbic acid, tocopherols α and γ, and total phenolics) and two AOA assays for 2 years in south Taiwan. Ample genetic diversity exists within C. annuum to increase AO content. Based on dry weight values, non-pungent C. annuum entries as a group were significantly greater than pungent entries for contents of β-cryptoxanthin (36%), ascorbic acid (65%), total phenolics (36%) and α-tocopherol (11%). Group means of the brown-fruited entries exceeded the means of red-fruited entries for capsanthin (34%), zeaxanthin (37%), lutein (36%), β-cryptoxanthin (71%), β-carotene (82%), ascorbic acid (19%) and α-tocopherol (40%). Red-fruited C. annuum entries ‘Verdano Poblano’ and ‘Guajillo Ancho’ from Mexico ranked among the entries highest for all carotenoids, ascorbic acid and α-tocopherol. The inhibition of lipid peroxidation (ILP) assay could be adopted for AOA characterization or selection because of high variation among entries and consistent entry performance over years. ILP was positively correlated with phenolics ( r =0.72**) and ascorbic acid ( r =0.58**) contents. Significant positive correlations were detected between most carotenoids as well as a significant positive correlation between ascorbic acid and total phenolics contents ( r =0.78**).

Projecting annual air temperature changes to 2025 and beyond: implications for vegetable production worldwide

Data sets were accumulated of annual average maximum, minimum and mean air temperature from a range of sites worldwide, specifically from non-urban locations such as agricultural research institutes, universities and other rural or island locations for the period 1975–2011 or longer where data were available. The data sets were then analysed using linear regression to determine the rate and direction of change in temperature over the reference periods. This analysis was performed to provide vegetable scientists with likely future temperature change scenarios up to 2025 and 2050 (on the assumption that recent trends are maintained) so that breeding, agronomic and other related research programmes may better respond to potential challenges from abiotic and biotic stresses to vegetable production. Substantial variation was evident between sites and between time runs at specific sites. At some locations rapid increases in air temperature are projected, such as for sites in East Asia, but at other locations little change is evident; in rare cases, local cooling is shown. The implications of variability and change in air temperature in the context of constraints to vegetable production and the opportunities to exploit the range of genetic diversity available in climatically uncertain environments are discussed. It is believed that modern agricultural science can address successfully the problems raised by climate uncertainty, yet the lack of sufficient, immediate investment in horticultural disciplines worldwide places the world at severe risk of failing to attain effective food and nutritional security.