Nitrogen applied as NH4-N or NO3-N (75 mg·liter-1) affected onion (AIlium cepa L.) plant growth when grown in solution culture. Nitrate alone or in combination with NH4-N increased leaf fresh and dry weight, leaf area, root fresh and dry weight, and bulb dry weight when compared to growth with NH4-N as the sole N source. Bulb fresh weight was highest with an NH4-N: NO3-N ratio between 1:3 and 3:1. Maximum leaf fresh weight was not necessary to produce maximum bulb fresh weight when onions were subjected to different N-form ratios. Precocious bulbing resulted when NH4-N was the sole N source; however, high bulbing ratios early in plant development were not correlated with final bulb fresh weight. Nitrogen form also influenced water uptake and pungency, as measured by enzymatically developed pyruvate concentration, but did not affect bulb sugar concentration.
S. Gamiely, W.M. Randle, H.A. Mills, D.A. Smittle, and G.I. Banna
D. Pluda, H.D. Rabinowitch, and U. Kafkafi
The effect of fertigation with N-NO3 at 3, 6, or 12 mmol·liter-1, and 0, 3, or 6 dS·m-1 chloride ions on fruit quality of three pepino dulce selections was studied. Genotypes varied considerably in their response to mineral treatments in most quality characteristics. Variation in fruit size was greatly reduced when clusters were thinned to three fruit. Increasing chloride concentration in the nutrient soltuion reduced fruit size significantly and ascorbic acid concentration relative to the control, but fruit shape was not affected. Increases in NaCl salt, but not N concentration, resulted in significantly higher soluble solids concentration (SSC) and firmness in all three genotypes. Electrical conductivity, acidity, and pH were significantly affected by the two mineral treatments in the first trial, but remained unchanged in the second season. Fruit firmness, SSC, and acidity declined by 12% to 30%, whereas ascorbic acid content increased during 14 days storage at room temperature. These changes depended on genotype and environment during fruit growth and development. Organoleptic ratings were highest in salt-treated plants. Fruit quality of pepino dulce may be manipulated by crop management, thus improving its acceptability in Western markets.
Esmaeil Fallahi and Ik-Jo Chun
Effects of rootstock and ground and fertigated applied nitrogen on productivity and fruit quality of `Fuji' apple was studied. In the fertigation portion of this project, treatments were as follows: 1) 22.4 kg N/ha per year, 2) 89.7 kg N/ha per year, 3) 89.7 kg N/ha per year plus 78.5 kg K/ha per year; 4) 156.9 kg N/ha per year; 5) 156.9 kg N/ha per year plus 78.5 kg K/ha per year. Fruit had optimum quality when leaf N concentrations were approximately between 1.9% to 2.15% dwt during light-cropping years and approximately between 2.12% to 2.40% during heavy-cropping years. Cross-sectional areas of `Nagafu-6 Fuji' trees were slightly smaller than those in `BC-2 Fuji' trees. Preliminary data also showed that mineral concentrations of leaves from various strains of `Fuji' do not significantly vary. In 1998, trees from 22.4 kg N/ha zone had lower leaf N, resulting in lower leaf area and lower photosynthesis but better fruit color than those with higher N applications. In 1998, trees on Ottawa-3 had higher yield than those on B.9, M.26, and M.7. Trees on B9 had lower leaf N and smaller fruit than those on other rootstocks. Fruit on M.7 rootstock were larger, but had the worst color among all rootstocks. Fruit on M.9 had better color than those other rootstocks. Trees with 2.43-m in-row spacing had significantly higher photosynthesis than those of 1.22-m spacing.
Esmaeil Fallahi and Brenda R. Simons
The influence of three rootstocks, various levels of soil-applied nitrogen in fall, and spring spray applications with and without minimum ground nitrogen on tree growth, productivity, leaf and fruit nutrient partitioning, and postharvest quality of fruit at harvest and after storage in `B.C. 2 Fuji' apple was studied over several seasons. Early results showed that trees on M.26 and M.9 were more precocious and had higher yield and yield efficiency. Trees on M.9 had significantly higher leaf Ca and incidence of sunburned fruit than those on other rootstocks. Trees on M.7 had larger fruit and higher leaf N, K, and Cu, but had lower fruit starch degradation pattern (SDP) and leaf Ca. Soluble solids at harvest were lower in fruit from trees on M.26 rootstock. Trees with fall nitrogen application had lower leaf N and better fruit color. Lower quantities of N application had smaller fruit but better fruit color and higher firmness at harvest. Fruit from all rootstocks did not produce ethylene for several days in the ripening chambers. After this period, fruit on M.9 rootstock produced ethylene before those from other rootstocks. Trees established with only nitrogen spray without any ground application had leaf N deficiency after they started bearing fruit. Establishment of a new `Fuji' orchard based on only nitrogen spray produced weak trees with low yield and yield efficiency, while addition of a small quantity of ground-applied N improved tree growth and fruit quality.
Esmaeil Fallahi, James R. McFerson, and Bahar Fallahi
Many fruit growers in the Pacific Northwest region prefer to use a sprinkler system to produce high-quality fruit and to establish a cover crop in the orchard. However, water shortage mandates the use of more efficient methods of irrigation, such as drip. In this long-term experiment, the effects of seven irrigation systems for `Fuji' and two irrigation systems for `Gala' on five rootstocks on tree growth, water use, fruit quality, and mineral nutrients were studied. All forms of drip systems used less water than full micro-sprinkler (SP). Partial root drying sprinkler (PS) used 50% less water than SP. Trees with partial root drying drip and deficit drip had to receive 65% of full drip to survive. Each `Fuji' tree with SP used about 5397 L of water in 2004 and 5833 L in 2005, while each tree with full drip used 2403 L in 2004 and 3438 L in 2005. Thus, trees with full drip used 41% to 55% less water than those with SP system without any reduction in fruit quality. This leads to a major savings in the cost of fruit production. Fruit weight in trees with full drip was always greater than those with PS or deficit drip. Fruits with SP system had lower soluble solids than those with PS. Fruits from trees with partial drip had a higher starch degradation than those with other systems. Leaf minerals, particularly N and K, were affected by irrigation systems. `Pacific Gala' trees on B.9 rootstock were more precocious than those on Supporter-4 rootstock. In general, `Pacific Gala' on RN-29 had better tree performance and fruit quality than those on other rootstocks. The calculation of water requirements on a tree-use basis provided an excellent guide for drip irrigation.
Bhimanagouda S. Patil, Kevin Crosby, David Byrne, and Kendal Hirschi
, 2011 ). Breeders should also consider taste and quality while breeding for nutritional benefits. These two parameters significantly impact the acceptance of fruits and vegetables. For example, increasing the levels of bioactive compounds that contribute
Verónica De Luca, Diego Gómez de Barreda, Antonio Lidón, and Cristina Lull
, drought, disease, and nutrition) to reduce polluting agricultural inputs such as fertilizers and pesticides. A priority for many turfgrass managers is to maintain high-quality turfgrass while minimizing their environmental risk. The objective of our
Hagai Yasuor, Alon Ben-Gal, Uri Yermiyahu, Elie Beit-Yannai, and Shabtai Cohen
source of bioactive nutrients such as vitamin C, provitamin A (carotenoids), phenolic compounds, and potassium, which define its nutritional quality and antioxidant capacity ( Flores et al., 2004 ). Carotenoids, particularly lycopene, are powerful natural
Adriana Contreras-Oliva, Cristina Rojas-Argudo, and María B. Pérez-Gago
also performed to determine changes during postharvest handling. At present, the nutritional quality is gaining interest, being a component of the overall quality that is very much valued by consumers. In particular, citrus fruits are an important
Carmen Mena, Alejandra Z. González, Raúl Olivero-David, and María Ángeles Pérez-Jiménez
structure and concentration of some compounds ( Ryan et al., 2002 ; Yousfi et al., 2006 ). These changes are reflected in the quality grade, sensory characteristics, oxidative stability, and nutritional value of the obtained product. The magnitude of these