Journal of Nuts
Year:2015 | Volume:6 | Issue:2 |Papers Count:8

Pistachio nut is a strategic product throughout the world, especially in Iran. There are some problems that reduce production and export of pistachios, for example, postharvest fungi, especially Aspergillus spp., that lead to production of mycotoxins. Nowadays the use of chemical and synthetic antifungals is discouraged and reduced because of health risks to mankind and nature. In present study we investigated the antifungal activities of carvacrol and allyl isothiocyanate (AITC) on conidia germination and mycelial growth in Aspergillus flavus at six concentrations and two observation times (3 and 7 days after inoculum). The results indicated that these compounds could inhibit spore germination and mycelial growth completely at 12 and 2.9 mL L-1 for mycelial growth and conidia germination, respectively. In addition, the ED50 and ED95 values were determined for all treatments. It was concluded that the natural compounds examined in the present study could be used as antifungal agents against food spoilage and mycotoxin producing fungi. Further studies on natural antifungal compounds to replace chemical fungicides are required.

Twenty isolates of Trichoderma harzianum were isolated from the rhizosphere of healthy pistachio plants from different localities of Kerman Province, Iran. Five isolates with high antagonistic activity in in vitro assays against Verticillium dahlia (the causal agent of pistachio wilt), were investigated for their effect on the defense enzymes, peroxidase (PO), phenyl alanine-ammonia lyase (PAL) as well as the total phenol and protein contents in pistachio seedlings exposed to V. dahlia under greenhouse conditions for one month after inoculation. The results indicated that all of five isolates had the ability to induce defense enzymes in treated pistachio seedlings; the Tr8 isolate had the maximum PAL activity and a corresponding increase in the total phenol content. The maximum PO activity and increase in total of protein ontentwere seen with the Tr5 and Tr19 isolates, respectively. The increase in the activity of these enzymes when pistachio seedlings treated with antagonist alone or in combination with pathogen was greater than for plants inoculated with pathogen alone. In addition, Tr8 induced a significantly higher level of resistance in pistachio seedlings; therefore it showed the highest inhibition about 45.4% of verticillium wilt disease. This study suggests that the increased induction of defense related enzymes results in increased total phenol and protein contents due to enhanced resistance to invasion of pistachio seedlings by verticillium wilt. Outcomes of the study will be useful in formulating T.harzianum isolates for control of verticillium wilt in pistachio plants.

In order to evaluate the inter-specific hybrid of P. atlantica ´ P. vera cv. “Badami Zarand” to salinity stress, an experiment was conducted as a factorial based in a completely randomized design with 0, 60, 120 mM salinity levels of NaCl2, CaCl2 and MgCl2 (3:2:1) on two rootstocks “Qhazvini” and “Badami Zarand” and an inter- specific hybrid of P. atlantica ´ P. vera cv. “Badami Zarand”. Mineral concentrations of sodium (Na), chloride (Cl), magnesium (Mg), calcium (Ca), copper (Cu) and iron (Fe) in shoot increased at 120 mM salinity level; however, the phosphorus (P) concentration in root decreased. Rootstocks had significant differences in the concentrations of elements of shoot. The highest concentrations of Na and Cl were observed in “Badami Zarand” and “Qhazvini” rootstocks, and the lowest was observed in hybrid rootstock. The highest concentration of Mg was observed in hybrid rootstock, and the lowest was observed in “Badami Zarand”. Due to restriction in the absorption and transport of chloride and sodium to the shoot, hybrid rootstock could tolerate more salinity than “Badami Zarand” and “Qhazvini” rootstocks.

Humic acid is a biochemical constituent of humus and increases root biomass and shoot growth by improving absorption of nutrients. In order to study the effects of humic acid on root and shoot growth and leaf nutrient contents of pistachio seedlings, an experiment was conducted of completely randomized design with five treatments in three replications. In the first step seeds of Pistacia vera cv. Badami-Riz-Zarand were planted in plastic pots containing vermiculite in March 2013. The humic acid treatments were of five levels (0, 20, 40, 60 & 80 g) and were applied to the seedlings at the four-leaf stage. Results showed that humic acid had significant effect on the plant length, internode distance, root length and width (root expansion) and root fresh and dry weight. The greatest effect was seen for 60 g of humic acid and the least in control treatment (0 g humic acid). In measuring leaf nutrient content in different humic acid treatments, the greatest amounts of Zn, Cu and Mn were in the 40-g humic acid treated plants. Overall, considering growth characteristics and leaf nutrient content, the best results for pistachio seedlings were obtained with about 60 g humic acid. Presumably, through an increase in root expansion, humic acid causes better absorption of nutrients and increased shoot growth. Therefore, humic acid can be used to increase shoot growth and expansion of root system in pistachio seedlings.

Among the most important problems of pistachio are physiological disorders such as fruit abscission and production of blank nuts. Environmental stresses and inadequate nutrition during flowering time have increased these problems in recent years. In order to evaluate the effects of foliar treatments with polyamines and other compounds (amino acids and ascorbic acid) on quantitative and qualitative traits in pistachio cultivars, an investigation was conducted using a factorial experiment base on a completely randomized block design (CRBD) at an orchard condition in the Rafsanjan region. This experiment was performed to evaluate three factors, 1) type of treatment (spermine, spermidin, amino acids and ascorbic acid) at 6 concentrations, 2) cultivar (،Ohadi,, ،Akbari, and ،Kalehghoochi,) with three replications and 3) year (2013 and 2014). Different traits, such as yield per shoot, number of nuts per cluster, fruit abscission, blank nuts, split nuts, deformed nuts, length and diameter shoot were measured. The results indicated that all of the treatments increased yield and percentage of split, and decreased fruit abscission, blank and deformed nuts in comparison with the control. Spermine (1 mM) combined with ascorbic acid and amino acid, had the most significant effect, increasing yield 50 % and split nuts 18 % and also decreasing fruit abscission 20 %, and decreasing blank and deformed nuts 5 % in all cultivars, in comparison with controls. Ascorbic acid and amino acid treatment without polyamines had a lower effect in comparison with spermine treatment combined with these compounds. The combined use of these compounds, e.g., 1 mM spermine, ascorbic acid (0.5 g/L) and amino acids (3 g/L) suggests that they might act as a suitable compound fertilizer in order to reduce fruit abscission and increase the yield of pistachio crops without the impact of environmental pollution.

Brassinosteroid as one of steroid hormones has an integral role in controlling plants physiological process especially in response to biological and non-biological stress. This research has been done in Damghan Islamic Azad University Greenhouse. The influence of four concentrations of plant growth regulator -24, homobrassinolide with concentration of 0,10-10, 10-8,10-6 molar on null seedlings of pistachio genotype sort based on factorials experiments on the basis of completely randomized block design with four replications was performed. After foliar spraying in six - leaves stage of pistachio seedlings and after passing six weeks, somephysio-morphplogical characteristics such as the size of photosynthesis pigments, leaf area index, seedlings height, biomass (the wet and dry weight of root and shoot), and lipoxygenase enzymes were scrutinized. The result indicated that foliar spraying experiment with brassinosteroid hormones had significant effect on some evaluated traits (P). Maximum leaf area index with concentration of 10-10 brassinosteroid and genotype G1, and the minimum leave area index with untreated (control) and genotype G5 were achieved. In biomass scrutiny, the wet weigh of aerial organs in level 1% was significant (5% level).The maximum weight of the wet weigh in concentration, 10-10 and the minimum weight in concentration of control and 10-6 were observed. Besides, the fresh weight of root in level 1% was significant, and the maximum weight with concentration of 10-10 and genotype G (22%) and minimum weight with control concentration and genotype G1 were observed. The maximum amount of lipoxygenase was related to concentration of 10-10, and genotype G2 and the minimum amount was related to null concentration of brassinosteroid hormones and genotype G1.

Self-incompatibility is one of the most important difficulties in almond production which reduce fruit set dramatically and makes orchard management difficult. Therefore, breeding almond to produce self-compatible genotypes is very important. In this research identification and screening of 86 almond progenies obtained from selfing Touno after the selfpollination by PCR reaction with specific primers of CEBASf and AS1. PCR results confirmed the situation of selfcompatible hybrids. In addition, it indicated that, frequencies of Sf, and S1 was 100% and 50% in progenies respectively. Self-compatible hybrids had been identified that can be used in almond breeding programs particularly to development the monoculture of almond orchards. So to identify and screening homozygous self-compatibility almonds be capable of be another step towards creating monoculture of almond and use in breeding programs further.

The almond, Prunus dulcis Miller which belongs to Rosaceae family, is one of the most important commercial and oldest cultivated tree nut crops. Almonds are classified as a ‘nut’ in which the edible seed is the commercial product. Therefore, pollination and fertilization are necessary in almond. The characteristic of cultivated almond to express gametophytic self- incompatibility discourages self-fertilization and favors cross pollination. Genetic control of pollen- pistil self-incompatibility is through a single gene (S) which exists in a series of alleles S1 to Sx. Compatibility of pollen-pistil in almond is an important consideration in planning crosses in breeding program and in choosing pollinizers for orchard planting. Identification of self-(in) compatibility in almond carried out by molecular and controlled pollination methods. In this study, identification of S-alleles in 37 Iranian almond cultivars and genotypes was carried out by PCR method with using degenerate primers of EM-PC3 cons RDEMPC2 cons FD, PaconsI-Fand EMPC1 cons RD. In this way the size of S -alleles were estimated based on bands which amplified with second intron. The results confirmed self-incompatibility in cultivars and most genotypes. However, the Sf-like allele (in size) was observed in A9 and A36 genotypes. If these results are confirmed by sequencing the Sf allele, it will be first time to identify self-compatible genotype in Iranian almond genotypes.