IRANIAN JOURNAL OF HORTICULTURAL SCIENCE AND TECHNOLOGY
Year:2008 | Volume:9 | Issue:1|Papers Count:7

Moisture stress, as limited amount and times of irrigation, is effective on crops. In order to study the effect of soil moisture stress at early growth stages on yield and tuber size of four potato cultivars, an experiment was conducted at Rozveh Research Station of Freidan, Isfahan province, in 2001and 2002. The experiment design was split-plot with a randomized complete block arrangement and four replications. Main factor included five irrigation treatments (I1, I2, I3, I4 and I5 were the first irrigation after emergence, based on 160, 240, 320, 400 and 160+160 mm evaporation from class A pan, respectively, which were equivalent to 16, 23, 29, 35 and 16+15 days). The next irrigations were performed after depletion of 35-40 percent available moisture in the top 60 cm of the soil profile in all treatments. In I5, the first irrigation was after 160 mm of evaporation from pan and the second irrigation was again after 160 mm of evaporation. Sub-factor included four cultivars: ‘Marfona’, ‘Concord’, ‘Agria’ and ‘Cosima’. The results showed that total yield and large tubers (> 55 mm) yield was higher in I2 treatment (33.35 and 19.04 tons ha-1, respectively) than the other irrigation treatments and I5 produced the lowest total and large tubers yield (28.56 and 14.86 tons/ ha-1, respectively). Irrigation treatments didn't have any significant effects on medium tubers (35-55 mm) yield, but small tubers (< 35 mm) yield in I5 was significantly greater than the other treatments. Number of main stems was not significantly different in irrigation treatments. ‘Marfona’ produced the highest total and large tubers yield (36.21 and 22.99 tons ha-1, respectively). Total yield of Concord was significantly greater than ‘Agria’ and ‘Cosima’ and also ‘Concord’ produced the highest medium and small tubers yield. Large tubers yield of Agria was significantly greater than ‘Concord’ and ‘Cosima’ cultivars. Water use efficiency was obtained as 3.54, 3.90, 3.73, 3.74 and 3.28 kg m-3 in I1 to I5 treatments, respectively.

A randomized complete block experiment with seven treatments and three replications was carried out in order to application of biological decomposing accelerators and comparison between effectiveness of this material with nitrogen to prevent developing and accelerate decomposing of thatch layer. The treatments included: the control, an American-made biological material (PHC)2 , Iranian-made biological material, urea, sulfur coated urea, American-made biological material (PHC) + urea and Iranian-made biological material + urea. The experiment was carried out at the reserve turfgrass grounds of Azadi Stadium in Tehran (Iran) using, with mixture Turfgrass: (60%) Lolium prenne L. + (40%) Poa pratensis L.) during 2005. Thickness of the thatch, turfgrass height, root length, leaf color, total nitrogen, chlorophyll content, and C:N ratio were determined at the end of the experiment. The results showed that the thickness of the thatch was maximum in urea (34.55 mm) and minimum in PHC + urea (10.77 mm); plant height was max. in urea (15.08 cm) and min. in control (12.38 cm); leaf color was max. in control (8) and min. in PHC and sulfur coated urea (7); chlorophyll content was max. in urea (0.024%) and min. in control and PHC (0.014%); C:N ratio was max. in control (16.57) and min. in urea (10.58) and total nitrogen content in urea was max. (4.6%) and min. in the control (2.98%). Treatments did not significant affect the root length of the turfgrass. Attention to results Iranian-made biological material + urea treatment is a suitable composition (due to low C:N ratio and comparison with control treatment thatch thickness is half in this treatment) for thatch control in turfgrass.

Effects of different methods of iron application on yield and chemical composition of Lisbon lemon was studied in a two-year research in Haji-Abad Research Station in Hormozgan province. The experiment was conducted on 49 Lisbon lemon trees with 8 meters interval between trees and 7 replications. The treatments were: Control, Traditional application, Surface application of 150 g Fe-EDDHA tree-1, Surface application of 500 g FeSO4 tree-1, Localized placement of 500 g FeSO4 tree-1, Surface application of 500 g FeSO4 tree-1 plus foliar application with 0.5% FeSO4 solution and finally Localized placement of 500 g FeSO4 tree-1 plus foliar application with 0.5% FeSO4 solution. Results showed that treatments caused statistical differences between plant responses at 5% statistical level. Maximum yield (195.4 kg tree-1), the most fruit average weight (156.7 g), the highest concentration of K and Fe and Zn in leaf (1.04%, 237.2 and 54.8 mg kg dry weight-1, respectively) and the most acidic pH of fruit were obtained with localized placement of 500 g FeSO4 tree-1 plus foliar application of FeSO4. However, in most cases, no significant difference was observed with elimination of Fe foliar application. Surface application of 150 g FeEDDHA caused 176 kg yield tree-1 and surface use of 500 g FeSO4 plus foliar application resulted 170.3 kg yield tree-1. Therefore, two recent treatments were common placed after treatments before. Surface application of 500 g FeSO4 tree-1 showed the least desirable effect on yield and fruit quality, after control treatment. Control treatment and traditional application treatment caused 153.4 and 158.3 kg yield tree-1, respectively. Fruit qualitative properties also diminished in these two treatments. So, they stood at the lowest step. Considering above mentioned results, in order to increase yield and improve fruit quality in Lisbon lemon cultivar, using 500 g FeSO4 tree-1 plus foliar application of 0.5% FeSO4 solution is strongly recommended.

Peach fruits have climacteric respiration pattern and limited storage life in some cases. In order to increase the storage life of ‘Elberta’ peach, fruits were treated with UV-C irradiation at 0, 5 and 15 min and then immersion of fruits in 0, 1 and 3% of CaCl2 solution. The experiment was carried out in a completely randomized design with factorial arrangements with three replications. The quality factors including flesh firmness, TSS, TA, TSS/TA, pH, weight loss and decay of fruits were measured. The results showed that the firmness of fruit irradiated for 15 min with UV-C were more than of fruits treated for 5 min and controls. Also irradiation had a significant effect on amount of decay and the decay was observed severely in controls. Irradiation was not effective on the other attributes. The firmness of fruit treated with 3% CaCl2 was more than that of controls and those that immersed fruit in 1% CaCl2. With increasing the concentration CaCl2, the TA was increased. The effect of CaCl2 on the percent of weight loss and decay was significant. The minimum of weight loss and decay was belong to the 3% CaCl2. The CaCl2 treatment did not have any significant effect on the other attributes.

Acidity content of fruits is influenced by preharvest environmental factors, horticultural practices and postharvest conditions. In this study, the effect of different heat treatments (temperature conditioning and hot water dipping) on acidity content and key enzymes activity in organic acid synthesis and accumulation of organic acid ‘Satsuma’ mandarin fruits was investigated. Acidity content and key enzymes activity signficantly changed during storage periods. Although activity of aconitase in juice sac declined during storage conversely, but isocitric-dehydrogenase (ICDH) activity increased slightly. During storage induced V-PPase and V-ATPase gene transcript level has increased in most heat treated fruits which was probably associated with acid content in the juice. Heat treatments could not influence significant differences in juice acid percentage. In contrast, sugar content and sugar to acid ratio may affected by heat treatments. The amount of V-PPase and V-ATPase gene transcript in fruit pulp considerably affected by various heat treatments.

Nutritional balance is an important factor in increasing the yield and improving the quality of orchard production. The DRIS system is a suitable method for determining the nutritional balance status of orchards using leaf analysis. In order to recognize nutritional disorders in vineyards, a four-year (1997-2000) field experiment was conducted in Kohgiluyeh va Boyerahmad province. For this purpose, leaf analysis data from high yielding orchards were used to establish DRIS norms for grapevines. The norms obtained for N, P, K, Ca and Mg were 5.05, 42.7, 1.42, 1.7 and 0.4 percent in leaf dry matter and for Fe, Mn, Zn, Cu and B were 206.5, 110.3, 61.5, 14.6 and 33.9 mg/kg, respectively. The established norms were used to calculate DRIS indices and nutritional balance index(NBI) for those orchards having low yielding. The results showed that mineral nutrients were imbalanced in low- yielding orchards and Fe, Cu, Mn, N, K, Zn, B and P deficiencies were in 56, 56, 53, 44, 44, 41, 41, and 41 percent of this orchards, respectively. Based on the results, relative nutrient demands in low yielding orchards were obtained: Cu>Fe>P>Mn>Zn>N>Mg>K=B>Ca.