نشریه تولیدات گیاهی
سال سی و ششم شماره 3 (پاییز 1392)

To evaluate the effects of seed priming on inducing of water stress tolerance, an experiment was carried out under laboratory and field conditions in Satloo station of Agricultural and Natural Resources Research Center in West Azerbaijan province at 2008-9 seasons. A factorial experiment was formed, with the first factor including four cultivars Zarrin and Shahriar (irrigated cultivars), Sardary and Azar (rainfed cultivars) and the second factor, hydro-priming, osmotic solutions (10% polyethylene glycol (8000), 2.5% KCL, 5% NaCl, 10% Urea, 4/0% Micro nutrient), plant growth regulators (1000 ppm Cycocel and 20 ppm Auxin) and non priming as a control. Treatments were arranged at laboratory in Completely Randomized Design and two separate experiments with Randomized Blocks Design under normal and water stress at field conditions with five replications. Irrigation was held at booting stage in water stress experiment. Results of analysis of variance showed that there were statistically significant differences for traits of plumule and radical lenghts and their dry weights, grain yield and its components, total dry matter and relative water content of lage feaf (P≤0.05). Pretreatment of Cycocel was allocated maximum plumule (17.8cm) and radical (17.2cm) lenghts and their dry weights (8.0 and 11.5mg, respectively). All priming treatments at four cultivars had more grain yield than control and at plant growth regulators were dominant and the highest variation percentage. Total dry matter (-10.7%), grain yield (-4.0%) and relative water content (-9.3%) at seed priming with potassium cholride had the lowest variation percentage under water stress than normal conditions. This pretreatment increased spike per squar meter in Shariar, Zarrin and Azar. Within cultivars, Azar with 0.89 susceptibility index was the most tolerance to drought stress. Traits of total dry matter, grain per spike and spike per squar meter observed positive significant correlations with grain yield at seed priming treatments, 0.91**, 0.92** and 0.79*, respectively. It seems that these traits could be used as an indirect criterion for selection of cultivars with high grain yield.

In this research, empirical models and Artificial Neural Networks (ANNs) were used for estimation of equilibrium moisture content of seed and kernel of sunflower. Four empirical models of modified Henderson, Chung-Pfost, Halsey and GAB were used. Two types of back propagation networks (feed forward and cascade forward) were tested. In order to train input patterns, levenberg-marquardt was used. Temperature and relative humidity limits for the experiments were between 25-40 °C and 11-96%, respectively. The best results for empirical models were obtained for Halsey and GAB models. The best results for applying neural networks were obtained for feed forward network, topology of 3-5-3-1 and threshold function of TANSIG-TANSIG-LOGSIG. With this optimum network, coefficient of determination and mean relative error were 0.9935 and 0.0501, respectively. These results prove the superiority of neural networks compared with empirical models, because besides producing less errors in prediction of equilibrium moisture content, neural also capable of networks are considering the quality index as an input parameter.

In order to evaluate the effect of Gibberellic acid and bed substrate on germination and different traites of Persian cyclamen (C.persicum), an experiment was conducted in 2008 at Zanjan University. A factorial experiment based on completely randomize design was carrid out with 20 treatments in three replications (60 plots). The effect of bed substrate was compared in four levels (filter paper, peat and perlite, peat and sand, and peat, perlite and sand) and Gibberellic acid in five levels (0, 100, 200, 300 and 400 mg/L). The results showed that the effect of bed substrate was significantly different (P=0/01) on germination percentage, germination rate and leaf area and was significant (P=0/05 ) on petiole length. However, petiole diameter did not differ significantly (P=0/05). All the gibberellic acid levels had a significant (P=0/01) effect on all the studied triats. The effect of bed substrate and Gibberellic acid interaction was significantly different on seed germinatin percentage and leaf area (P=0/01), petiole length and germination rate (P=0/05); however, it had no significant effect on petiole diameter. The highest seed germination percentage, germination rate and leaf area were obtained in a3b3, a4b3 (Peat and sand substrate and peat, perlite and sand substrate with concentration of 200 mg/L gibberellic acid), in petiole diameter triat a3b1 (Peat, perlite and sand substrate without gibberellic acid) and in petiole length triat a2b5 (Peat and perlite with concentration of 400 mg/L Gibberellic acid).

In this study, we investigated strawberry seeds (Fragaria ananassa cv.Camarosa and Paros) germination where they scar using different concentrations of Sulfuric acid (1, 12, 24 and 36 N), in both types of in vitro culture medium of Murashig and Skoog (MS) and gamborg (B5) and wet filter paper (W). This experiment was performed in Shahid Chamran University of Ahvaz during 2011 on factorial experiment using Randomized Compeletly Design in 5 replications. The reated seeds with 4 concentrations of Sulfuric acid established in the culture medium of MS and B5 without vitamins and plant growh regulators and on wet filter paper mediun were investigated for germination indices. Germination percentage, germinatin rate, average radicle and plumule length (two week after germination) were analyzed. The results showed no germination in control treatment (no scarification seeds) and in scarification of seeds with 1, 12 and 24 N Sulfuric acid concentrations in the 3 types of culture medium (MS, B5 and wet filter paper (w)) during the experiment (40 days). However, scarification of seeds with 36 N concentration of Sulfuric acid in all types of culture medium showed the maximum seed germination index in B5 culture medium and minimum seed germination index in wet filter paper medium.

Pistacia atlantica Desf. mutica is a dioecious plant. In addition to having a high nutrition and medical value, it is considered as an important Pistacia vera stock because of desirable properties. Pistacia species has along juvenile stage and persumably marker assistance selection can enhance its breeding program. Sequence Characterized Amplified Region (SCAR) has been used to determine sex in Pistacia atlantica Desf. mutica. In this experiment,9 leaf samples of known male and female trees and 1unknown sample were collected and tested with a pair of SCAR primers. According to the results, only anapproximately 300 bp fragment was amplified in all female trees and it was absent in male trees. Although sex determination mechanism in Pistacia is still unknown, since correlations between SCAR marker and sex locus, we can useSCAR marker could be used for sex determination in Pistacia atlantica Desf. Mutica seedlings.

In order to investigate the effect of row spacing and seeding rate on Mesa-Sirsa alfalfa cultivar, this experiment was carried out in the research farm of Khuzestan Agricultural Research Center between 2000 and 2004. The research was performed in the form of a split plot in a randomized complete block design with 3 replications. The main plots were three row spacing’s (50, 60 and 70 cm) and the sub plots were five seeding rates (5, 10, 15, 20, and 25 kg seed per ha). The Traits were racemes lm2, pods/raceme, seeds/pod, 1000 seed weight, seed and biological yield and hoarest index. The effects of year were significant different on all the traits. Seeding rate did not have any significant effect on pods/raceme, seeds/pod and 1000 seed weight. The highest seed yield was obtained from 50 cm row spacing. Seed and biological yield increased as row spacing. Decreased using the highest seeding rate (25 kg/ha) produced the highest biomass yield (5034 kg/ha). The highest significant correlation was observed between race/ms/m2 and seed yield (r= 0. 922٭٭). According to the results, for alfalfa (var. Mesa-Sirsa) seed production in South Khozestan province, using 15 kg/ha seed and 50 cmrow spacing, that produced the highest seed yield due to increase in race/ms/m2 and 1000 seed weight, is recommended.

Mango is one of the important fruits in tropical regions of the world. A basic problem of its production is alternate bearing. Observation of phenotypic behaviors at maturity phase is used to screen alternation bearing in mango seedlings obtained from controlled hybridization. To evaluate the relationship among polyphenol oxidase enzymes and bearing patterns of tree at the juvenile stage, an experiment was done at Minab during 2008-2010. In this study, 8 mango genotypes with known bearing patterns (alternate or non-alternate bearing) were chosen. Scion of every genotype was grafted on its own rootstock, and then the activity of Catecholase and Cresolase was measured (60 days after grafting). The results showed correlations between low enzyme activity and regular bearing genotypes, with regular bearing trees having lower Catecholase and Cresolase activity than alternate ones. Also, correlation was observed between catecholase and cresolase activities with fruit number production per tree (r= -0.86 and -0.74 respectively) which could be used as an early screening index of mango seedlings.

In order to study the effect of plot water height on some agronomical and physiological characteristics of rice cultivars in Ahvaz, a field experiment was conducted experimental field of Ramin Agriculture and Natural Resources University in Ahvaz, in the during 2005- 2006 growing season. Treatments were arranged as a split-plot experiment in a randomized complete block design with three replications. Water height at four levels (5, 10, 15 and control: with water flowing) and three cultivars (Champa, Anbori and Danial) were the main plots and sub plots respectively. The results indicated that by increasing the height of plot water, the grain yield, number of grain in panicle and plant height increased, but at 15 cm water height a relative decrease in grain yield was seen. Also, by increasing plot water height, HI, number of tillers, water use efficiency and water temperature decreased but plot water height had no significant effect on 1000 grain weight. Among the cultivars, Danial and Champa had the highest and lowest grain yield, number of grain in panicle, tiller number and water use efficiency, respectively. If the water height, for decreasing of water usage, increasing water use efficiency and grain yield, in different cultivars is fixed, the 10 cm of plot water height inAhvaz region can be recommended.

Salinity affects plant growth by the osmotic stress of salt around the roots as well as by toxicity caused by excessive accumulation of salt in leaves. An investigation was set up to study the effects of salt stress on stomatal conductance, growth rate and the relation between them.Six selected wheat cultivarsthat were previously identified as contrasting in salt stress tolerance (Roshan, Kavir, Bam, Gaspard, Shiraz and Qods) with three salinity levels (0, 100 and 200 mM NaCl) were used in a pot experiment, using a factorial experiment based on completely randomized design with three replications. Stomatal conductance was reduced at 1, 10 and 20 days after plants were exposed to salinity, and a similar result was obtained for relative growth rate at 10 and 20 days after exposure to salt. However, the reduction was greater in salt sensitive cultivars as compared with tolerantones. Results showed that stomatal conductance acts as a tool for screening of osmotic stress tolerance which was reduced immediately after the onset of salinity, while relative growth rate was declined in the first 10 days exposure to salt. Cultivars with high stomatal conductance maintained a higher growth rate under salt stress. High stomatal conductance in short-term salinity exposure was related to high growth rate over a long period of time. A positive relationship between stomatal conductances with relative growth rate indicated that stomatal conductance can be a reliable indicator of the photosynthesis and growth rate and can be considered as a sensitive indicator of the osmotic stress toleranceand other abiotic stresses.

In order to study water deficit stress on safflower in different stages of growth, this experiment was conducted in Shahid Chamran University during 2009 – 2010 growing season in a split plot test based on randomized complete block design with three replications. The main factor was irrigation levels including I1: full irrigation, I2: withholding irrigation at bud stage until final growing season, I3: withholding irrigation during flowering until final growing season and I4: withholding irrigation at grain filling until final growing season and the subplots were two safflower: Goldasht (ILL.111) and Padideh (LRV.51.51). Results showed that stop irrigation in bolls stage (extreme water deficit) caused significant decrease in seed and oil yield, 1430.8 kg/h and 306.7kg.h respectively. Water stress significantly increased in proline content (547.12mg.kg). In the other hand, withholding of irrigation at grain filling until seed maturing stage had no significant effect on oil and proline content. Extreme water deficit stress resulted in more decrease in crop growth rate (CGR) and relative growth rate (RGR) compared to non control treatment. In the water stress condition, relative water content (RWC) decreased. The highest oil yield was obtained in Goldasht cultivar and the lowest oil yield in Padideh cultivar was observed. The research results showed watering restrictions during the grain filling stage sharply decreased in product performance, but quality did not. Accordingly, water management and economy in using water can help produce economical products.

The influence of different rates and split application (AP) of Nitrogen (N) on qualitative and quantitative characteristics of first sugarcane ratoon (Saccharum officinarum L.) cultivar CP48-103 were investigated. The study was conducted at the Sugarcane Research Center, 30 km South of Ahvaz during 2007 - 2008. The experiment was a split plot randomized complete block design with three replications, consisting of three different rates of N (N1, 92; N2, 138; N3, 184 kg N ha-1) as the main plots and three different split applications from urea fertilizer (AP1, 20-40-40%; AP2, 30-35-35%; AP3, 30-30-40%) in tillering, early stem extension and stem elongation stages as subplots. Results showed that both the rate and split application of N had no significant impact on sugarcane characteristics. However, the maximum stems and sugar yields were obtained by using 138 kg N ha-1 which was split to 20-40-40% (AP1) with values of 91.7 and 10.6 t ha-1, respectively. The highest nitrogen use efficiency was for the N1 treatments with 281.7 and 43.2 kg kg-1Nin stems and sugar yields, respectively. Results also indicated no significant effect of nitrogen application rates on sugarcane final yields; thus, the excessive application of N is not recommended in sugarcane farms.