مینا غزائیان

To select the high yielding and adapted pecan genotypes for Dezful climatic conditions in Iran, 50 seedling trees were evaluated in 2019-2021 in Dezful in southwest of Iran. The results showed that P200-7 and P200-8 genotypes had the largest and smallest nuts with 14.3 and 4.2 grams, respectively. P220-2-1 genotype had the highest and P200-9, and P220-2-5 genotypes had the lowest percentage of blank nuts. Kernel removal was easy in P200-1 and P200-10 genotypes, while it was very difficult in P200-3 and P200-31 genotypes. Fruit ripening time was the earliest in P200-1 and P220-2-5 genotypes and the latest in P200-23. P200-23, P220-1-1 and P200-9 genotypes had the highest yield index with 65, 49 and 39 g cm-2 of tree trunk, respectively. The results of evaluation for heat stress tolerance in pecan genotypes showed that 40 to 70% of the branches of all genotypes were damaged by hot temperatures in the summer of 2021 with 430 hours of temperatures above 45 oC, while the branches of P200- 23 genotype were not damaged. In addition, the results indicated that heat stress damage had significant correlation with yield index (r = 0.311*) and kernel color (r = 0.323*). There was highly significant (r = -0.597**) correlation between shell thickness and kernel removal. The relationship between mean fruit weight and nut length (r = 0.386**) and nut width (r = 0.440**) were also highly significant. Factor analysis showed that nut length, shell thickness, blank nuts percentage, nut weight, yield index and heat stress damage accounted for 67% of the total variance. Finally, P200-23 genotype with high yield index, golden bright kernel color and very high heat stress tolerance, and P220-1-1 genotype with high yield and low percentage of blank nuts were identified as promising genotypes for future supplemental research.

To assess the vegetative rootstock effect on some vegetative and reproductive characteristics of peach and nectarine commercial cultivars, a study was conducted in Golestan agricultural and natural resources research center, Iran, from 2012 to 2017. Six commercial cultivars; Kuota, Independence, J. H. Hale, Dexired, Redtop and Redgold, were grafted on Penta, Tetra and GF677 rootstocks. The greatest fruit yield efficiency was observed in Dexired and Independence on Penta, and the least in Redtop on GF677. The highest fruit yield per tree was obtained from J. H. Hale on GF677, and the lowest belonged to Independence on Penta. Also, the amount of total soluble solids (TSS) was significantly affected by rootstock and cultivar, and was the highest in cv. Redtop on the Penta. The lowes TSS, however, was measured in cv. Redtop on the GF677. The highest fruit acidity (pH) was in J. H. Hale on GF677. The effect of rootstock on the TCSA (tree cross sectional area) was significant, and the greatest was measured for cv. Redtop on GF677, and the least belonged to Redgold and J. H. Hale on GF677. The TCSA was the highest in GF677 and lowest in Penta. The largest canopy developed in cv. Redtop on GF677.

Leaf curl is a serious disease on peaches and nectarines. Planting of resistant varieties is one of the best ways to prevent and control this disease. In this research, 17 peach and nectarine cultivars were evaluated for susceptibility to the causative agent of peach leaf curl. The results of the evaluations in the first year indicated that, the highest disease severity was related to the Caldesi 2000 and July Alberta cultivars, based on the reaction type of cultivars, they were placed in the sensitive group (S). Then, Red Skin, Baby Gold, Springtime and Antonia cultivars had the highest disease severity and all of them were classified as semi-resistant (MR) cultivars. In contrast, Amesdan, Redhaven, Springcrest and Fayette respectively had the lowest severity of the disease, and all were highly resistant (HR). In the second year of evaluation, Springtime and Caldesi2000 cultivars had the highest rate of disease severity and according to the reaction type of cultivars, both of them classified, highly susceptible (HS). Then July Alberta and Baby Gold cultivars were susceptible to disease (S). In contrast, Amesdan, Redhaven and Robine cultivars had the lowest severity of disease and according to the type of cultivars reaction were classified highly resistant (HR). Therefore, according to the results of two years evaluation, it can be said that the cultivars Caldesi2000, Springcrest,then July Alberta and Baby Gold are the most susceptible and Amesdan and Redhaven are the highest resistance to the peach leaf curl disease.

To study yield and different traits and select the suitable apple cultivar for Golestan province, some vegetative traits and fruit quantitative and qualitative characteristics of five commercial apple cultivars Golden delicious, Red delicious, Braeburn, Red spur and Fuji grafted on MM106 were evaluated in Shahkoh during 2013-2015 using a completely randomized design with three replications and three trees in each replication. The highest yield efficiency was 0.49 kg per cm2 of trunk cross area in Red spur cultivar followed by Braeburn, Fuji, Golden delicious and Red delicious. Maximum firmness (5.74 kgcm-2) was in Fuji cultivar and minimum (4.82 kgcm-2) in Braeburn.The highest amount of total soluble solids and acidity were in Golden delicious cultivar (13.37 and 1.45, respectively). Results of simple correlation analysis indicated the existence of significant, positive or negative correlations between some characteristics such as fruit dimensions and skin thickness and cultivar. Based on the obtained results and due to short season growth period in shahkoh mountains, early to medium season ripening cultivars and semi-standard to standard rootstocks can be recommended for cultivation in this region.

Jujube (Ziziphus jujube) belongs to Rhamnaceae family. It is considered not only for medicinal usage، but also is cultivated as an ornamental plant due to its beautiful leaves and trunk. The first step in a plant breeding program is to collect native genotypes of a plant in a region and evaluate them for selection of superior genotypes. Jujube is grown naturally in some areas of Iran، as well as in Golestan province. In the present study ten ecotypes of jujube grown in this province were collected from different areas and their phonological and morphological traits as well as some fruit characteristics and qualitative factors such as vitamin C، pH and total soluble solids (SST) were evaluated during years 2009 to 2011. Different vegetative، morphogic and fruit traits such as flowering thme، branch angle. Length of one year old branch، number of thorn on branch، fruit weight، length and width، stone weight and length، flesh weight، flesh/stone ratio، vitamin C، TSS and fruit pH were measured based on jujube descry. The results showed a high diversity for different traits among the ecotypes. The results also showed that vegetative traits were affected considerably by geographical and climatical factors. Ecotypes prown in west of the province where humidity is high، showed characteristics different from those grown in eastern regions. Fruit characteristics were also influenced by environmental factors.

Characteristics of forty pecan genotypes in Golestan province were evaluated for three years using pecan descriptor. Cluster analysis based on quantitative and qualitative traits of fruit, fruit shape and maturity time, divided genotypes into ten main groups. Factor analysis was employed for defining the determinant factors, and the characteristics constituting each factor. The effective traits were categorized within four factors which accounted 70% of total variance. Within each factor, characters with coefficient values of more than 0.5 were considered significant. Factor analysis revealed that the traits of fruit shape, nut and oil percentage, kernel fresh and dry weight, fruit dimension, length to width ratio and shell thickness were some of the characteristics that constituted the main factors. Based on the obtained results and observation through these three years, six trees (genotypes) G2, G3, G4, G19, G20 and G28 showed better performance than the other genotypes.

The harvesting time and storage conditions of olive fruit are effective factors on the quality and quantity of oil. The harvesting time of olive is different in each area and it depends on climatic conditions.This investigation was carried out to assess the impact of harvesting time on olive oil quality and quantity frome two olive varieties cultivated in Gorgan region. For this reason fruits of selected cultivars, Mishen and kroniki, were harvested with fifteen-day intervals from 6 september till middle desember. Then quality and quantity of oil was determined. The results showed that dry matter, oil content (in dry), free fatty acids increased during ripening, whereas peroxide value decreased during ripening. Therefore, the best harvesting time for these cultivars is beginning of December.