نشریه به زراعی نهال و بذر
سال بیست و پنجم شماره 4 (1388)

To study effects of different nitrogen levels on grain yield, grain protein content and agronomic nitrogen use efficiency in wheat genotypes under optimum and post-anthesis heat stress conditions, two separate field experiments were conducted in optimum and delayed sowing dates in Ahwaz, Iran in 2007 and 2008 crop cycles. The experimental site had a mild winter and dry and hot summer. Plants in delayed sowing date experienced heat stress during post-anthesis. Split-plot arrangement were corried out in a randomized complete block design with three replications in each experiment. The N application rates; 50, 100, and 150 KgNha-1 assigned to the main-plots. Sub-plots consisted of six bread and durum wheat genotypes. Results indicated that in both optimum and post-anthesis heat stress conditions, grain yield (GY) decreased significantly as nitrogen level decreased. High temperature during grain filling period reduced the average of grain yield and TGW, 24% and 31%, respectively. Agronomic nitrogen use efficiency (ANUE) reduced as the N level decreased. In post-anthesis heat stress conditions reduction in ANUE was 47.8% as compared with optimum conditions. The average grain protein content (GPC) was between 11-12.6% under optimum and between 12.6-13.8% under post-anthesis heat stress conditions. Higher rates of N fertilizer and also post-anthesis heat stress led to higher GPC. Grain protein yield per unit area increased by 9% under heat stress conditions as compared to optimum conditions. Low GY was associated with high GPC and low protein yield under post-anthesis heat stress conditions.

Eight grapevine training systems were compared for their effects on yield, vegetative growth, and fruit quality in Vitis vinifera L. cv. Sefid Bidaneh in Grapevine Research Station of Takestan Qazvin, Iran. The cost of establishment of systems, fruit bearing index, shoot growing rate, TSS, TA, pH were assessed and measured. Vines were own-rooted, spaced two meter apart in three meter wide rows over five growing seasons 2002-2006. The main objective was to determine training system effect on fruit bearing index, shoot growth, fruit quality and fruit yield in a context of efficient vineyard management. Training systems were Guyot, Low cordon spur pruned (LCSP), High cordon spur pruned (HCSP), Geneva double curtain (GDC), Head training spur prune (HSP), Simple cordon spur pruned (SCSP), Y system (Y) and Traditional training system (TTS) in Iran. Vines were annually spur-pruned in all systems of training. The greatest year-to-year variation in yield occurred in Head spur pruned (5.2 kg/vine) and Geneva double curtain training (2.25 kg/vine). Fruit bearing index of SCSP was greatest (1.45) and lowest in Geneva double curtain (0.85). Individual berry weights were consistently least in TTS (0.86g), and greatest in Guyot (1.21g). Fruit from Y training systems had more rates of sugar accumulation (TSS) during four seasons (24.5) in which repeated measures of fruit maturity were made and lowest rate of TSS observed in LCSP and TTS (21.25). Titratable acidity of fruit juice was lowest in HS and Y systems (0.546 mg/100cc). Fruit from Y system had highest pH (4.15) and lowest pH observed in HCSP (3.24). Vegetative vigor of vines (kg/vine) were least in Guyot (2.19) and greatest in TTS (2.45). The greatest year-to-year variation in bud break reduction occurred in HCSP (24.58%) and lowest in HS (16.15%).

Immature capitulum of gerbera cultivar of Tropic Blend, after disinfection and removal of sepals, divided into four parts, and cultured on 1/2MS medium supplemented with 0.05, 0.1, 0.5 and 1 mg/l TDZ and 0.1 mg/l IAA. The remainings were also cultured in 1/2MS medium, supplemented with 5, 10 and 15 mg/l BAP and 1 mg/l IAA. Cultures were incubated in dark conditions and then transferred to the light. There was not any prolifration in 1/2 MS medium suplemented with different concentrations of BAP. The highest number of plantlets was obtained in 1/2 MS supplemented with 0.05 mg/l TDZ. For prolifration, plantlets were produced in MS medium supplemented with 2, 4, 6 and 8 mg/l kinetin. The highest and lowest number of plantlets were producted in MS medium with 2 and 8mg/l kinetin and 1 mgl IAA, respectively. The highest number of leaves was produced in 2 and 4 mg/l kinetin. For rooting, plantlets were cultured in MS medium supplemeted with 0.5 and 1 mg/l NAA. The highest number of roots was produced in MS with 0.5 mg/l NAA. For acclimatization the rooted plantlets were transferred into pots. They were throughly acclimized.

Increasing in application of phosphate fertilizers and their expensiveness are reasons to seek a way to use phosphate rocks directly in agriculture. Zeoponic substrates are new approach for using phosphate rocks (apatite) in plant production. This study was carried out to determine phosphate rocks efficiency in zeoponic substrate in greenhouse rose culture in Tehran University, Faculty of Agriculture in 2004-2005. Two different kinds of Iran’s apatite rocks with different characteristics were used in five substrates as main-plots and five different nutrient solutions for nourishing the plant were used as sub-plots in a split-plot arrangement-using randomized complete block design with three replications. Apatite content in substrats, solutions concentration and phosphorous element varied in this investigation. Results showed that root growth and root dry weight in substrates without apatite or of low amount of apatite, were greatr than other treatments. Different nutrient solutions had no significant effect on root growth, however, root dry matter production reduced when solution concentration reduced and phosphorous was eliminted from the nutrient solutions. Phosphorus content of roots in substrates that had low amount of apatite was greater than other substates including control, however, this differences were not significant. Solutions that contained high concentration and phosphorous element resulted in high phosphorous content in roots in comparison with solutions contained low concentration and without phosphorous element, but the differences were not significant.

This study was conducted to evaluate the effect of composted azolla on some growth and nutrient compositions of ornamental plants using Ficus benjamina cv. Starlight as a model plant. The trial was carried out as factorial experiment using randomized complete block design with three replications. Five levels of nutrition including: a1) Nutrient solution without composted azolla, a2-a5) without nutrient solution and with 0, 100, 250 and 400 g/pot composted azolla and four types of growing media including: tea wastage + tree bark, 1:4 v:v; tea wastage + leaf mold, 1:4 v:v; tea wastage + tree bark, 1:4 v:v; and tea wastage + leaf mold, 1:1 v:v were applied as treatments. Some important growth characteristics were measured over the 11-months of experimental period. At the end of this period, aerial parts of the plants were harvested to be analyzed for their nutrient elements composition. Results showed that the application of 100 g/pot composted azolla not only improved quality of the appearance of the plants, but also increased the macro nutrient elements accumulation in the aerial parts of plant as compared to the other treatments. It was concluded that azolla-contained growing media can be successfully substituted with some expensive conventional peat – based growing media.

To determine the effect of zinc and auxin foliar application on grain yield and its components of grain maize (Zea mays L.) cv. SC 704] under water deficit condition, this study was conducted in Agriculture Research Center of Varamin in south–east of Tehran in 2006 crop cycle. There were three water deficit levels: 50%, 60% and 70% water depletion of available water in soil (main-plots), factorial of zinc and auxin foliar application (sub-plots) (zinc foliar application in four levels: sulphate, EDTA, water spraying and no spraying and auxin spraying in three levels: spraying, without spraying and water spraying, respectively) arranged in a split plot–factorial using randomized complete block design with three replications. Results showed that only water deficit × auxin spraying interaction was not significant on grain yield and grain protein and oil contents. Zinc (sulphate and EDTA) × auxin spraying interactions in 50% and 60% water depletion of available soil water had the highest grain yield with 12410 and 11840 kgha-1, respectively. In addition, the effect of two zinc complex and auxin spraying in different water deficit levels on grain yield and yield components varied, but showed positive effect on grain yield and its components at the same water deficit levels.

This study was conducted to evaluate effect of different summer sowing dates and plant densities on yield and yield components and some agronomic characteristics of baby corn cv. KSC403 su (Zea mays L.) in Agricultural and Natural Resources Research Center of Khorasan Razavi Province, Mashhad, Iran in 2008 cropping season. This experiment was carried out using split plot arrangements in a RCBD with four replications. The sowing date (14th June, 3th July, 24th July) and plant densities (65000, 85000 and 105000 plant. ha-1) were assigned in main and sub plots, respectively. Results showed significant differences between different sowing date for palnt height, dehusked and husked baby corn yield, ear height, stem diameter, ear length, ear diameter, standard and sub-standard dehusked baby corn yield, standard and sub-standard ear percentage and fresh forge yield. The highest baby corn yield of 13240 kg ha-1 obtained in 24th July sowing date. Delay in sowing date led to increase of growth period and suitable weather (cooler temperatures) at anthesis, therefore, ear yield increased, but ear length decreased and ear diameter increased. Ear marketing decreased, not only for fresh consumption but also for industry. Plant density had significant effect on stem diameter, no. of ear/plant, plant height, dehusked baby corn yield, fresh forage yield, standard and sub-standard dehusked baby corn yield and harvest index. The highest baby corn yield was harvested from the highest plant density (722 kg ha-1). Finally, the interaction of sowing date × plant density was significant only for standard ear percentage (p<0.05). Sowing date 14th June with planting density of 105000 plants ha-1 was determined as suitable package for baby corn production and marketing in Mashhad region.

This study was carried out to evaluate factors affecting establishment and proliferation of two apricot × plum (Prunus armenica × Prunus domestica) interspecific hybrids; HS405 and HS706. These hybrid rootstocks are resistant to diseases and pathogens and have been developed in East Azarbayjan Agricultural and Natural Resources Research Center, Tabriz, Iran. Propagation of these hybrids through cutting and grafting proved to be difficult due to some physiological disorders. Therefore, vegetative propagation using tissue culture can be a reliable method for mass production of healthy plant materials from these new rootstocks. Nodal explants were surface sterilized by immersion in 70% ethanol for 30 seconds, followed by 2. 5% sodium hypochlorite for 7 and 10 min depending on the tissues, then rinsed three times with sterile distilled water. Cultures were established on MS and WPM media supplemented with BAP (0, 1 and 2 mg/l) + 0.05 mg/l NAA and effects of 3 sampling dates (spring, summer and autumn) were evaluated. After four weeks, surface and internal infection, shoot necrosis, percentages of active buds were recorded and a scoring index system (1- 4) was developed for determination of buds growth quality. WPM medium supplemented with BAP (0, 1, 2 and 4 mg/l) + 0.5 mg/l GA3 was used in proliferation stage and after four weeks number of shoots, average shoot length, shoot quality index, leaf number, leaf length and leaf chlorosis index were recorded.All media were supplemented with 3% (w/v) sucrose and 0.7% agar and the pH was adjusted to 5.7 before agar addition and autoclaving. All the cultures were maintained in growth room at 24±1ºC and 16-h photoperiod under 40 µM m-2 s-1 illumination created by white fluorescent lights. The experiments were set up as factorial in completely randomized design (CRD) with five replications, each containing four explants. Data were analyzed using SAS software and the means were compared by Duncan’s Multiple Range Test at the 5% probability level. In establishment stage the highest percentage of active buds and bud quality index achieved from explants collected in spring. HS405 genotype had higher number of active buds compared to HS706. WPM medium was better than MS in establishment stage. The highest percentage of active buds was achieved in hormone-free medium that without significant difference with the medium containing 2 mg/l BAP + 0.05 mg/l NAA. In proliferation stage, genotype HS706 had higher shoot length and quality index as compared to HS405. The best treatment for shoot proliferation was 4 mg/l BAP + 0.5 mg/l GA3 without significant difference with the medium containing 2 mg/l BAP. In vitro propagation of fruit species particularly interspecific hybrids have many of difficulties. In vitro propagation of two apricot × plum interspecific hybrids, HS405 and HS706 was investigated for the first time, in Iran.