نشریه به زراعی نهال و بذر
سال بیست و هشتم شماره 4 (1391)

To study climatic elements and adaptability of agricultural crops in Kabootarabad agricultural research station of Esfahan, thermal and humidity variables were used (1986-2008). Normal distribution was used for estimation of occurrence probability of maximum and minimum critical temperatures and returning period. Daily mean temperature, day length, relative humidity, precipitation and sun shine hours were 15.2 °C, 12.43 hours, 39.5%, 115.8 mm and 3245.5 hours, respectively. Probability (%) of 0 °C and less from Oct. 21 to Nov. 30 and March. 6 to April. 6 varied from 1 to 99%. Probability (%) of 37 °C and more than that from May 23 to July 12 varied from 1% to 99%. January and July had the maximum and minimum relative humidity of 60.9% and 23.4%, respectively. Spring, summer, fall and winter mean precipitation were 30.3, 3.1, 24.2 and 58.2 mm, respectively. Therefore in this station there is low risk of minimum and maximum temperatures on growth and development of agricultural crops provied reliable water sources for irrigation requirements are available, and there is no limitation of day length and sunny hours for growth and development stages of most crops.

Mycorrhizal fungi can preserve plant against environmental stresses, such as drought, by symbiosis with host plant. A greenhouse experiment was conducted as factorial in completely randomized design with four replications. The objectives of this experiment were evaluation of effect of two species of arbuscular-mycorrhiza (AM) fungi and three different levels of drought stress (Non-stress, mild stress and severe stress) on root colonization, plant growth parameters (leaf, shoot and root dry weight, plant height, basal stem diameter and leaf number per plant), mycorrhizal dependency, leaf chlorophyll content and leaf P concentration of Citrus aurantifolia rootstock in agriculture research station of Darab, Iran, in 2009-2010. Results showed that all measured parameters were negatively affected by drought stress. The negative effect of drought on plant root were greater than those of plant shoot. However, shoot and root dry weights of citrus plant colonized by two species of AM fungi were significantly higher than those of NM plants at all of moisture levels. A similar trend was observed for other plant growth parameters under drought conditions. Both species of AM fungi improved phosphorous (P) nutrition uptake of the host plant under drought stress. The observed decline in beneficial effects of mycorrhizal colonization with increasing drought stress was attributed to the significant decrease in root colonization. It was concluded that AM colonization, particularly G. mosseae, improved drought tolerance of citrus rootstock and compensated, in part, for the deleterious effect of drought stress.

Asian pear is a new horticultural crop in Iran, therefore, its management for higher yield and higher quality can play an important role in its economic production in appropriate growing areas. This study was carried out to determine a mathematical model between fruit diameter with volume and fresh weight and pomological evaluation of six cultivars of Asian pear including early (KS7, KS6), mid (KS11, KS13) and late (KS8, KS12) season. This study was carried out in research orchard of horticultural science department, Tarbiat Modares University, Tehran, Iran in 2008-2010. Fruits diameter, volume and fresh weight were measured by destructive and non destructive methods. Results of the relationship between diameter and volume and fruit fresh weight indicated that there was a strong correlation between fruits diameter with volume and fresh weight in all cultivars. There was no significant difference between measured fruits volume and fresh weight in comparison with estimated data based on fruit diameter which showed appropriate equations were finely fitted model to estimate the fresh weight and volume of fruit using fruit diameter. General equations from combined data of six cultivars showed that Y= -6.43+2.703X and Y= -6.31+2.68X were the best fitted models for estimating fruit volume and fresh weight based on fruit diameter, respectively. Evaluation of pomological traits showed that fruit loss (%) in late cultivars was high, thus their ultimate fruitset was low. Also there was significant difference in fruit yield between different cultivars. Therefore, KS13 with 6.01 kg tree-1 had the highest fruit yield and KS12 with 2.91 kg tree-1 had the lowest fruit yield.

Pear (Pyrus communis L.) such as many members of Rosaceae is self-incompatible and for adequate bearing needs suitable pollinizer cultivars. This research was carried out to determine suitable pollinizer (s) for some important native pear cultivars. Reciprocal crosses were made between Shah Miveh, Shekari, Natanzi, Sebri, Dar Gazi and Bartlett cultivars. Fruitset (%) and number of viable seeds per fruit were considered as indices of pollen compatability. In addition to above combinations, these indices were also evaluated in natural and artificial self pollinated as well as open pollinated trees. Artificial selfing showed advantage to the natural selfing for overcoming the incompatibility barrier in Sebri and Bartlett cultivars. Moreover, pattern of fruitsets in open pollinated trees were in accordance with commercial bearing potential of the cultivars. In cross pollinated combinations Dar Gazi led to highest fruitset with 10.2%, 5.1% and 0.86% as pollinizer for Sebri, Shekari and Natanzi cultivars. This cultivar also demonstrated 90% of blooming overlap with Sebri, and 50% with two other cultivars. Apparently, high compatability of Dar Gazi as a pollinizer for other pear cultivars stems from its genetic distance that leads to existence of different self incompatibility alleles in this cultivar.

Spinach is an important leafy vegetable and consumed as fresh and processed. To study the effect of autumn sowing date and planting method on yield and yield components of spinach cv. Varamin 88, a field experiment was carried out in 2006-2007 and 2007-2008 growing seasons in agricultural research station of Varamin, Varamin, Iran. The experiment was conducted as split plot arrangement in randomized complete block design with four replocations. Three planting methods (flat, one row on the middle of 60 cm bed and two rows on 60 cm bed) were randomized in sub plots, and three autumn sowing dates (05 November, 21 November and 06 October) were assigned to main plots. Yield, length and width of leaf, duration from sowing to harvest, leaf number plant-1 and weight of ten plants were measured and recorded. Results showed that autumn sowing date of 05 November and planting of two rows on 60 cm bed was the best treatment for spinach cv. Varamin 88 in Varamin and similar regions.

To study the effect of sowing data on seed and oil yields of safflower a field experiment was carried out in agricultural research station of Varamin in 2006 and 2007 growing seasons as split plot arrangement in randomized complete block design with four replications. Four sowing dates (06 November, 21 November, 06 December and 21 December) were assigned to main plots and four safflower cultivars (Local Isfahan, Goldashat (Il-111), Padideh (L.R.V. 5151) and Sina (PI.53.75.98)) were randomized in sub-plots. Combined analysis of variance showed that interaction effect of cultivar × sowing date was significant (P<0.01) on most of the traits except number of seed head-1. Mean comparisons revealed that Goldasht produced the highest seed yield (3395 kg ha-1), 1000 seed weight (40.6 g) and number of branches plant-1 (16.6). Local Isfahan variety had the highest days to flowering (191 days), oil yield (823.4 kg ha-1), head number plant-1 (39 head) in 21 November sowiong date.

To determine chickpea genotypes competition ability against weeds, 49 chickpea genotypes were evaluated under weeds-free and weedy conditions using 7 × 7 simple lattice design with two replications in 2006 in Kheirabad Agricultural Research Station of Zanjan, Iran. Each plot was equally divided into two sub-plots in which the first sub-plot was weed-free and the second was left with weeds to grow naturally. Results of correlation between seed yield and its components with weeds density (in two growth stages) and dry weight (in one grown stage) showed that weeds density in early days of plant growing had the highest reduction of seed yield. Factor and correlation analyses and biplot method of grain yield in both conditions showed that MP, GMP, STI indices were more suitable for identification of genotypes with higher yield stability. Cluster analysis based on tolerance indices and yield under weeds-free and weedy conditions grouped chickpea genotypes in four clusters and genotypes of higher tolerance were located in the first and second clusters. The more sensitive genotypes with the largest margin were located in the fourth cluster.

Wild mushroom identification, domestication and their comparison with commercial strain and their later usage in breeding program is very important. Samples of Pleurotus with similar morphological characteristics were collected from Lakan forest located in west of Guilan province and cultured on MEA, PDA, LA and V8 media and incubated at 15, 20, 25 and 30 °C. Spawn were prepared after completion of spawn run on medium and mushroom was cultivated on rice straw. After harvesting, identification of species was carried out using PCR and micro and macroscopic characteristics. Results showed that domesticated species is Pleurotus pulmonarius. The highest mycelium growth rate (8.44 mm day-1), the shortest duration for mycelium growth completion (5.66 days) and the highest mycelium dry matter (58.5 mg 5 ml-1) were obtained from samples grown on MEA and incubated at 25 °C. This species had 20.37% of protein.

To determine the most suitable sowing date on yield and fruit characteristics of greenhouse tomato, this research was carried out in Larestan region of Fars province in Iran in 2010. The experimental factors included three sowing dates (06 September, 20 September and 04 October) and four greenhouse tomato cultivars (Feroun, Chelbas, Ergon and Uksel) were arranged as factorial in randomized complete block design. Results showed that sowing date had significant on days to beginning of harvest, vitamin C content and fruit yield. The highest fruit yield (391875 kg ha-1), vitamin C content (29.98 mg 100 g fwt-1) and economic income (173500000 Toman) belonged to sowing date of 06 September. The highest vitamin C content (32.05 mg 100 g fwt-1) belonged to cv. Uksel. However, the highest fruit yield (420833 kg ha-1) and economic income was obtained from cv. Chelbas. Ergon cultivar had greater fruit yield than cv. Feroun, but its economic income was less mainly due to its lesser market acceptance. In conclusion, cv. Chelbas was identified as a suitable greenhouse tomato for being sown in 06 September in Larestan region in Fars province in Iran.

Propagation of apricot with seedling has led to high genetic variation in apricot in orchards in Iran. Maragheh 90 cultivar is one of the recently released new apricot cultivars that has been selected from the local apricot population of north-west of Iran. Evaluation of morphological and pomological characteristics of Maragheh 90 showed that this cultivar has good adaptability to different regions. The fruit of this cultivar has the required properties for processing and fresh fruit such as; flesh firmness, high transportability, long post-harvest life, free stone, high TSS, red over color and good taste. On the other hand, the productivity and fruit quality of this cultivar is higher than most of other local varieties. Also fruit flesh firmness, suitability for fresh consumption and TSS in Maragheh 90 is higher than "Canino" cultivar. This cultivar is self-incompatible and "Aybatan" and "Nasiri 90" cultivars have been determined as its pollinizers. This cultivar has good graft compatibility with "Mirobalan" rootstock. It is recommended for most apricot growing areas of Iran.

Ordubad 90 is one of the recently released apricot cultivars that was selected from the local apricot population of the north-west of Iran. Ordubad 90 has been evaluated in different environmental conditions and showed high adaptability. This apricot cultivar is high yielding and has the required properties for processing and induatrial purposes. Ordubad 90 had 13 ton ha-1 of fruit yield with firm flesh, high transportability, long shelf life, free stone large fruits (58 g) and high TSS (24%). This properties has made it suitable for industrial purposes. Ordubad 90 is self-incompatible and cv. Aybatan and cv. Canino were determined as suitable polinizars for it with 57% and 46% fruitset, repectively. Ordubad 90 has also grafting compatability with Mirobalan rootstock and is recommended for areas with heavy soils.