نشریه به زراعی نهال و بذر
سال بیست و پنجم شماره 1 (1388)

An experiment was cobducted during two years 2002 and 2003 in Neishabour, to study the effects of sulphur and micronutrient fertilizer on yield and quality of onion. The experiment was in split plot factorial form in complete randomized block design with three replications. Two onion cultivars (Ghermez Azarshahr and Sefid Qom) were arranged in main plots and different sulphur amounts (0, 150, 300 and 450 kgha-1) and number of foliar applications with complete micronutrient fertilizer (0, 1, 2 and 3 sprayings with 6/1000 concentration) in subplots. Each plot was six meter long with 30cm row distance. The results of combined analysis of variance on data showed the ratio of height/diameter of onions, number of storage leaves, concentration of sulphur and nitrogen (NO3-) in two cultivars were not significantly different, but neck thickness, number of multiple growing points, potassium, Manganese and copper concentrations were affected by experimental factors. Interaction effects of year×cultivar showed significant differences between bulb yield and number of multiple growing points, number of edible layers and copper concentration. Application of 450 kgha-1 sulphur (with Thiobacillus bacterium) and two foliar micronutrient fertilizer resulted in the highest concentration of potassium of bulbs in all treatments. Bulb yield was affected by year, cultivar and sulphur fertilizer amount, but number of foliar applications had no effect on bulb yield. Application of 150 kgha-1 sulphur fertilizer decreased nitrate concentration in bulbs, but two foliar applications of micronutrient fertilizer increased significantly the concentration of nitrate in bulbs of cultivar Ghermez Azarshahr (195.4 ppm). Foliar application of micronutrient fertilizer and 450 kgha-1 sulphur fertilizer decreased nitrate concentrations of bulbs significantly.

Effects of drought stress through interruption of irrigation at different growth stages on seed yield and some agro-physiological traits of safflower were studied at Seed and Plant Improvement Institute, Karaj during 2002-2004 cropping seasons. The experiment design was a split plot that arranged in completely randomized block with three replications. Six interrupting irrigation treatments S1 (blooming and seed development), S2 (blooming and flowering), S3 (blooming), S4 (flowering), S5 (seed delopment) and S6 (control) were arranged in main plots and three spring safflower cultivars Isfahan local, Arak 2811 and FO2 in subplots. The results of combined analysis demonstrated that the differences among treatments were significant(P<0.01) for seed yield. The highest seed yield belonged to Isfahan local (1258 kgha-1) in non-stress condition, that was not significantly different from that of S5(seed developing) treatment (1159 kgha-1).The highest damage on seed yield caused by S2(blooming and flowering stress) indicated that blooming and flowering are two important stages in safflower growth period. The lowest damage was observed in S5(seed developing) treatment. It was concluded therefore that S5 stage could be a suitable stage for irrigation interruption in safflower cultivars. The crop growth rate (CGR) increased in different interrupting irrigation levels up to flowering stage and decreased afterward. The lowest amount of RGR observed at S2 stress treatment. Based on the results, interruption of irrigation at seed development stage has less effect on seed yield but can save irrigation water in safflower farms.

In order to investigate the competition effects between redroot pigweed and grain sorghum in different levels of plant density, an additive series experiment (response model) with factorial in randomized completely block design were conducted in 2005 growing season at research farm of Agriculture and Natural Resources Research Center of Khorasan Razavi (Torogh research station). Two factors were involved in the experiment, redroot pigweed density in four levels (0, 2, 8 and 16 plant m-2) and sorghum density in three levels (10, 15 and 30 plant m-2). Result showed that pigweed density had significant effects (p<0.01) on biomass and grain yield of sorghum. By increasing pigweed density, biomass and grain yield of sorghum decreased significantly (p<0.01), and maximum yield loss was obtain in 16 plant m-2 of weed density. Redroot pigweed growth indices and yield were significantly (p<0.01) affected by sorghum density. By increasing density due to increased intra and inter competition, sorghum biomass yield decreased. Results of this study determined that sorghum density had significant effects on redroot pigweed and sorghum competition. By increasing sorghum density, competition ability of sorghum was increased and yield loss decreased. By increasing sorghum density, intra specific competition index of redroot pigweed decreased.

To evaluate the effects of rootstock and different irrigation levels on quality and quantity of apple fruit, an apple garden in Kahriz Agricultural Research Station was selected to conduct the research plan for four years. The experiment was in a split–block design based on randomized complete blocks with three rootstocks (MM111, M26 and MM106) and three levels of irrigation (100%, 75% and 50% requirement water) in three replications. Results of combined analysis indicated that the effect of year on TSS and annual growth rate was significant at 5% and on yield at 1% levels. The highest TSS rate was obtained in the first year and the highest vegetative growth rate and maximum yield were assessed in the second year. The effect of rootstock on vegetative growth was significant at 5%. The effect of irrigation on TSS and fruit weight was significant at 5% and on vegetative growth rate at 1%. The higest TSS rate was found in irrigation treatment of 50% and maximum annual vegetative growth rate was found in irrigation treatment of 100% water requirement. The highest fruit weight (165.13) was also obtained in irrigation treatment of 100% water requirement. The effects of year and irrigation levels on TSS, yield per tree and per hectare were significant and the hieghest TSS rate was found in 50% irrigation level in the first year. Maximum yield per hectare was obtained in 100% water requirment treatment in the second year. The intraction effects of rootstock in irrigation level on firmness, yield per tree and per hectare were significant. The highest of firmness rate was found in M26 in 100% requirement water. Maximum yield per tree and per hectare was found in M26 in 100% requirement water. Water use efficiency (WUE) increased with decreasing water consumption in all treatments and maximum WUE obtained in 50% water requirement treatment on MM111. In this study M26 and 75% water requirement treatments had better effects on fruit quality and quantity and also on WUE.

Dracaena marginata Ait. (Madagascar dragon tree) and Beaucarnea recurvata Lem. (Elephant foot or Linda) are important foliage pot plants in Iran and worldwide. Suitable media is the most important parameter for growing of pot plants. The present experiment was carried out with 11 treatments in four replicates for application of agricultural or industrial wastes and evaluation of their effects on growth of foliage pot plants dracaena and elephant foot. Results showed that media containing 50% tree bark and 50% tea waste, 50 or 80% tea waste and 50 or 20% perlite, respectively and 67% leaf mould and 33% tea waste (grower's medium) had the highest effect on number of produced leaves and plant height, or tuber diameter in dracaena and elephant foot. Media containing 80% tree bark and 20% municipal compost and 80% tea waste and 20% rice hull had suitable effect on number of produced leaves produced leaves and tuber diameter of elephant foot. Based on the results of this investigation, municipal compost, with low volume, can be used for growing of pot plants that are tolerant to nearly high electrical conductivity (5 mS/cm). Dracaena and elephant foot plants in desirable media, provided from agricultural or industrial wastes in this experiment, showed higher growth than in commercial media containing 50 or 80% peat and 50 or 20% perlite, respectively.

In order to investigate the effects of sowing time and different nitrogen levels on quantitative and qualitative characteristics of oil flax, an experiment was performed in split plot in form of randomized complete block design, in four replications during 2005-2006 and 2006-2007 cropping seasons in Yasuj Agricultural Research Station. Five sowing times as the main plots were 4,6,8,10,12 on the basis of planting depth temperature, and four fertilizer levels as subplots were 0, 50, 100 and 150 kgha-1 pure N from urea source that 50% was used at the time of sowing and 50% as top-dressing. The results of combined analysis of data indicated that with delay in sowing decreased plant height, number of branches, number of fruits, grain yield, 1000 seed weight, leaf area index, dry matter, crop growth rate and oil percentage significantly. The use of 100kgha-1 pure N significantly increased plant height, number of branches, number of fruits, grain yield, leaf area index, dry matter and crop growth rate. The first sowing time with 1801.12 kgha-1 had the highest and the fifth sowing time with 760.48 kgha-1 the lowest seed yield. The highest and lowest seed yield in 100kgha-1 pure nitrogen treatment were 1895.22 and 1351.87 kgha-1, respectively. The highest oil yield (34.6%) obtained in the first sowing time. The first sowing time with 52.38% produced the highest and the fifth sowing time with 50.58% produced the lowest acid linolenic. Sowing time had no significant effect on acid oleic and acid linoleic. The highest acid linolenic 52.64% and acid linoleic 15.36% were obtained by the use of 150kgha-1 pure nitrigen and the most acid oleic 20.59% were obtained in the treatment without use of nitrogen.

A significant increase in the area under cultivation of walnut has been occurred during recent years, the propagation was done using the sexual propagation. One of the difficulties is obliging to use this method, was the low success in propagation by grafting methods. This study was done to evaluate the effects of rootstocks and cultivars on graft take of walnut. For this purpose, the seeds of Serr cultivar and Z63 genotype, after stratification, were planted in pots and maintained in greenhouse at 25° C. Three months after germination of seeds, morphological characters of canopy (after removal of the leaves) and roots were recorded on each rootstock (the offsprings of two cultivars) and then seedlings were grafted with scions of Hartley, Chandler, Z63 and Z30 cultivars and genotypes using hypocotyle method. The grafted plants were kept in greenhouse in 26° C and 90-95% relative humidity for one month, and grafting success in different treatment combinions, were studied. The results showed that offspring of Serr cultivar were more vigorous and significantly different from vegetative vigour of the offspring of Z63. The graft take was also higher on offspring of Serr (65.8%) in comparison with Z63 (46.7%). The graft take was also significantly different among the cultivars. Chandler and Z30 with 80% and 36.7% showed the highest and lowest grafting success respectively. There was also an interaction effect considering both factors (rootstocks and scions) so that all cultivars except Z63, showed better results on Serr rootstoks.

To study the effects foliar application of nitrogen, boron and zinc on fruit set and some quatitative and qualitative characteristics of Thampson seedless grape (Keshmeshi cultivar), an experiment was conducted for two years (2001 and 2002) in two vineyards in Uromieh using factorial based on randomized complete block design. Treatments were urea (0, 0.5 and 1%) zinc sulphate (0 and 0.15%), boric acid (0 and 0.13%) and their combinations that applied at seven days before full bloom and fruit set formation. Different quatitative and qualitative characteristics of fruits and fruit set formation were measured in different treatments during the experiment. The results showed that foliar application of nutrient elements had significant effects on fruit set. The highest fruit set percentage was recorded in treatments contained zinc, and the lowest percentage in control and treatments that urea and boron were used alone or in combination. The results of leaf analysis showed also that application of zinc increased zinc contents of leaf tissues up to 68.1 ppm, but appli cation of nitrogen and boron had not any remarable effect on their content in leaves. Nutrient elements application did not have any effect qualitative trails of fruit in the first year, but in the second year zinc containing treatments alone or in combination with urea (0.5%) increased bunch weight significantly. Generally, application of nitrogen, boron and zinc (0.5, 0.15 and 0.15%, respectively) had a positive effect on fruit set, but the role of zinc was much more than the effects of the other two elements.