JWSS - Journal of Water and Soil Science

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Experiments were conducted to evaluate the effects of heat and cold treatments on the disinfestation of dry figs from Estahban. Tow types of packing bags (with or without holes), two storage conditions including one at 23^oC and one cold storage condition (10^oC and 2^oC), 9 heat and cold treatment durations (3, 4, 5, 6, 7, 10, 15, 20 and 25 hrs) and 13 temperature treatments [23, 45, 55, 60, 65, 70, 75, 45+(-25), 50+(-25) and 60+(-25) ^oC] were used in these experiments. The results showed that Indian meal moth, Plodia interpunctella, which is a major pest in dry fig storage, can be satistfactorily controlled by packing figs in plastic bags with a thickness of 0.24 mm after suitable temperature treatment. Cold storage at 2^oC significantly controlled all developmental stages of moths at storage. Temperature treatments at 60^oC for 7hrs or more, at 65^oC for 6hrs or more, and at -25^oC for 15hrs or more were found to be capable of controling pest most satisfactorily without changing fruit external quality.

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‘Golden Delicious’ apples were vacuum infiltrated (250 mm Hg) with 0, 4, and 6% solutions of CaCl₂ followed by heat treatment for 0, 48 and 72 hours at 38^oC. Treated fruits were stored at 0^oC with RH of 85-90% for 2.5 and 5 months, followed by one week of storage at 20C. The results showed that fruits treated with 4 and 6% of CaCl₂ significantly increased calcium content of fruits after 2.5 and 5 months of storage at 0^oC. With increasing calcium content, fruit firmness also increased. There was a positive relationship between fruit firmness and calcium content and regression coefficients after 2.5 and 5 months of storage at 0^oC were 0.77 and 0.83, respectively. Heat treatment for 48 and 72 hours at 38^oC significantly increased fruit firmness. Calcium chloride at 4 and 6%, plus heat treatment, significantly increased fruit firmness of those fruits held for one week at 20^oC after removal from cold storage. In the second experiment, vacuum infiltrated fruits with 4 and 6% solutions of CaCl₂ plus potassium permanganate (0, 10, and 20 g/bag) had no significant effect on fruit firmness, but potassium permanganate alone significantly increased fruit firmness.

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Experiments were conducted during 1996-1997 in Nough of Rafsanjan to evaluate double pollination on fruit set and development of pistachio nut. In the first experiment, Owhadi cultivar was pollinated by a combination of pollen from Beneh (P. mutica F&M), Atlantica (P. atlantica Desf) and Soltani (P.vera L.). In the second experiment, Owhadi cultivar was pollinated by pollen from Beneh, Atlantica and Khinjuk (P. Khinjuk). The results showed that in the double pollination experiment, the nut, kernel and fruit set were affected more by the first pollen than by the second one. Pollen from the wild pistachio species reduced kernel weight, number of split nuts but increased percentage of the deformity and blank nuts in Owhadi. It was concluded that the effectiveness of the first pollen on fruit set, nut and kernel development was independent of the second one. The pollen of P. vera proved to be the best pollen source for pistachio cultivars.

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Green skin (hull) of pistachio fruits is a barrier against the penetration of fungi and insects into the kernel of pistachio. Splitting of husk facilitates the entry of fungi and infection of pistachio kernels during the harvest. So far no effective way has been reported for controlling this problem. To evaluate the effects of gibberellic acid on hull spliting the present research was conducted in a commercial orchard of pistachio during 2001-2002 in Rafsanjan, Iran. Gibberellic acid (GA₃) at 0,25,50 and 100 mg ^–1 was applied on 25-year-old of “Owhadi” pistachio cultivar. Two branches of each tree was sprayed during two years of study. GA₃ at 25,50 and 100 mg ^–1 significantly reduced hull splitting and penetration by Aspergillus spp. into pistachio fruits. There was a positive correlation between the hull splitting and fungi penetration (r=0.92^*). The exocarp, mesocarp and endocarp of pistachio fruits cultured on selective medium of Aspergillus spp. showed no infection of pistachio kernel by Aspergillus spp. The highest concentration of aflatoxin was detected in the kernel of non-treated fruits (6.25 ppb) and the lowest (0.5 ppb) fruits treated by GA₃ . GA₃ reduced husk slippery of pistachio fruits at harvest. The rate of husk slippery was reduced by increasing the concentration of GA₃. Gibberellic acid treatments had no significant effect on dehiscence, weight of 100 fruits, total soluble solids, but significantly increased fat and chlrophyll content of kernel of pistachio fruits. The results of the study is recommended for commerical pistachio production in Iran.

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This research was conducted to investigate the changes of GA₃-like substances in the stratified (0, 10, 20, 30 days at 10^oC) and non-stratified seeds of two olive cultivars, namely ‘Arbequina’ and ‘Zard’. In the first experiment stratified seeds of these cultivars (10 g) were extracted with ethanol (80%), purified by ethyl acetate, and then separated by thin layer chromatography (TLC). To compare the biological activity of separated zones, lettuce hypocolyl assauy was used. The results obtained in this part of study indicated that the amount of GA₃-like substances increased as the stratification period increased. In the second experiment extracts were made from different parts of non-stratified seeds of both cultivars. The result of the second experiment showed that the GA₃–like substances of embryos of non-stratified seeds were higher than other parts of the seed.

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To evaluate the effects of chemical and hand fruit thinning on pistachio flower bud retention, experiments were conducted during 1382 and 1383. In the first year, ethephon treatments at the concentrations of 100 and 200 mg L^-1, urea at 2.5% and 5%, naphthaleneacetic acid (NAA) 125 and 250 mg L^-1 and naphthaleneacetamide (NAD) 250 and 500 mg L^-1 were sprayed on two branches of nine uniform trees with four replications. During the second year, hand fruit thinning treatments were used in addition to the previous treatments. Chemical treatments reduced flower bud abscission among them ethephon treatments were the most effective on flower bud retention. As compared with other treatments, hand thinning treatments had also positive effect on flower bud retention. Fruit thinning also increased kernel weight, reduced the number of nuts per ounce and decreased blank fruits. Fruit thinning had no significant effect on the yield of branches during ‘on’ year.

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To evaluate the effects of heat treatments on sprouting weight, loss and other charactristics of two potato cultivars (Agria and Diamont) in cold (9±1) and ambient (18±1) storage, a series of experiments were conducted in 2004. In this study, after curing, the tubers of both cultivars were treated with warm air, at 25, 35, 45 and 57^oC for 4, 8 and 12 h and with warm water at 22, 54 and 57 for 15 and 30 min. Treated tubers were packed in net bags and were kept in cold and ambinent storage for 2 and 4 months. The results of the study indicated that warm air at 45^oC for 8 and 24 h and warm water at 57^oC for 15 min. in comparison to control reduced the percentage of tuber sprouting significantly, without internal changes in tubers composition.