فصلنامه علوم زراعی ایران
سال یازدهم شماره 4 (پیاپی 44، زمستان1388)

Drought stress is the most important limiting facor in rainfed agriculture all over the world. Generally, in the west Asia region, chickpea is cultivated as a rainfed crop, and its pod- filling phase often sufferes from late season drought which significantly reduces seed yield. To study the genetic variation and to determine the relationship between seed yield and some agro- morphological traits, the reaction of 103 accessions of Kabuli chickpea core collection of Natioanl Plant Gene Banak plus three improved cultivars (Jam, Arman and Hashem) was evaluated under four moisture conditions: normal (T1), low (T2), medium (T3) and limited (T4), using line source irrigation system. Experiment was conducted in Karaj Research Field Station Seed and Plant Improvement Institute, Karaj, Iran in 2006-07 cropping season. Different agro- morphological traits have been measured and recorded. Descriptive statistics nalysis revealed that there were significant variation in number of sub- branches, plant dry weight, number of seed per plant, harvest index, 100 seed weight and seed yield. Seed weight per plant had the most coefficience of variation. Variation in stress tolerance and susceptibility indices suggested a high genetic variation in studied Kabuli chieckpea genotypes. The correlation between seed yield, in stressed and non-stress conditions, and different drought tolerance indices indicated that STI and GMP were the more suitable indices for screening of Kabuli Chickpea genotypes for drought tolerance. Comparison of three dimension plot and bi-plot showed that in T3 condition, genotypes no. 67, 68 and 74 and in T4 conditions, genotypes no. 45, 47,105 and 110 were of higher drought tolerance.

Effects of seed priming in Zn and P solutions (with 10, 50 and 100mM Zn from ZnSO4 and 10, 50 and 100mM P from KH2PO4, respectively) on seed vigor, seedling establishment and grain yield of barley were evaluated in laboratory and field conditions (in autumn and spring plantings) in 2005- 2006 cropping season. Laboratory experiments were conducted as factorial on the basis of completely randomized design and field experiment was carried out as y randomized complete block design. Analysis of variance of laboratory data showed that percentages of viable seeds and germination, electrical conductivity (EC) of seed leakages, germination rate, root and shoot dry weight and seedling dry weight were significantly affected by Zn priming. All, but EC, were affected by P priming. Zn×P priming interaction was also significant on all traits. All of these traits decreased, with increasing Zn concentration in priming solutions. However, these qualitative traits increased, with increasing P concentration up to 50 mM. Further increases of P concentration resulted in reducing the traits. Priming in 10 mM Zn, 50 mM P, 100 mM P, 10 mM Zn + 50 mM P and 10 mM Zn + 100 mM P solutions were superior as compared to the other priming solutions, in the laboratory. Thus, these priming treatments were applied on seeds taht were used for autumn and spring plantings. Field traits were not significantly affected by priming treatments in spring sowing. However, in autumn sowing, the highest emergence rate and winter survival was achieved by 100 mM P + 10 mM Zn priming. In general, priming treatments, particularly 50 mM P + 10 mM Zn and 100 mM P + 10 mM Zn improved grain yield of barley up to 41% in autumn planting. Highest biological yield in autumn belonged to 100 mM P priming treatment and was 34% greater as compared with check. In conclusion, priming could icrease grain yield and biological yield in average by 29% and 16%, respectively. Therefore, these priming solutions can be applied to improve field performance of winter barley in rainfed conditions.

To study changes of volume of vacuole meristemic cells at the root tip of rice under saline conditions, suspension–cultured cells and protoplasts from three rice genotypes including IR29 (susceptible), and IR651, Ahlami-Tarom (tolerant rice cultivars) were treated with 0.1 M NaCl, 0.2 M mannitol, 20 nM bafilomycin A1, 0.1M NaCl complemented with 20 nM bafilomycin A1 and distilled water (as control). Sampling carried out at 3, 8 and 24 hours after application of treatments. Results showed that vacuolar volumes increased only in tolerant cultivars when treated with NaCl. However, after exposure of cells to the mannitol with osmolarity similar to 0.1 M NaCl, such drastic changes were not observed in the vacuole volumes, indicating that salt-specific effect responses in vacuoles. Furthermore, bafilomycin A1 completely inhibited the increase of vacuolar volume due to NaCl effects. This findings suggest that the V-ATPase may play an essential role in energizing a Na+/H+ antiporter activity as well as vacuolar Na+ compartmentation in meristimeic cells at the root tip of rice.

To evaluate crop yield, shelled kernel for conserving and determining the forage production of sweet corn (Zea mays L. var Saccharata) in pure stand and intercopped with mungbean (Vigna radiata L.), a field experiment was conducted in Varamin region, east Tehran, Iran in 2006 summer cropping season. Experiment was carried out in a split plot arrangement in a randomized complete blocks design with four replications. Plant density at three levels including 6, 8 and 10 plant.m-2 for sweet corn, cultivar S.C.403 and 10, 20 and 30 plant.m-2 for mungbean cultivar, Partow were assigned to main plots and five mixing ratios [(P1) = 0:100, (P2) = 25:75, (P3) = 50:50, (P4) = 75:25, (P5) = 100:0 for sweet corn:mungbean, respectively] were randomized in subplots. Quantitative attributes such as plant height, sucker numbers, Leaf Area Index (LAI), dry matter partitioningn in different plant organs were measured and recorded in the soft dough stage in sweet corn. Furthermore, the ear yield, ear for conserving and yield components of sweet corn and mungbean were also measured and recorded. Results showed that plant density had no significant effect on concerned traits, however, the effect of mixing ratio was significant (P<0.01). Therefore, the mixing ratio of 75:25 (sweet corn:mungbean) could be introduced as the superior mixing ratio, because it produced maximum amount of total biomass in sweet corn as well as forage yield, yield and yield components of ear in intercropping. Regarding the intercropping profitability indices, the mixing ratio of 75:25 (sweet corn:mungbean) in low density (D1P2) with LER=1.03 for total crop yield before ear harvesting and and LER=1.09 for total forage yield after removing the ears, was more profitable than sweet corn or mungbean monoculture. Therfore, sweet corn:mungbean intercropping would be a reasonable field management startegy to fill the time gap between two sequential cereal crops in regions with warm summer similar to this experimental site.

This study carried out to determine the effect of row spacing and planting density on some agronomic characteristics of safflower cv. Kooseh a local variety from Isfahan in summer planting. The experiment was conducted at the Research Field Station, Isfahan University of Technology in 2004- using a split plot arrangement in a randomized complete block design with four replications. The main plots were assigned to row spacings including; 20 and 30 cm in flat planting and 45 cm in bed planting and the sub-plots were planting densities including 40 and 50 plants.m-2. Plant height and 1000 seed weight were not significantly affected by row spacing. Number of stems.plant-1, number of heads. stem-1, number of heads.plant-1 and number of heads.m-2, number of seeds.head-1, seed yield.plant-1 and per unit area, harvest index and oil content (%) and oil yield were significantly reduced as row spacing increased. The effect of planting density on plant height, number of heads.stem-1, 1000 seed weight, seed yield per unit area, harvest index and oil content (%) and oil yield were not significant. Number of stem.plant-1 and per unit area, number of seeds.head-1, number of heads.plant-1 and number of heads per unit area and plant yield significantly decreased as planting density increased. The highest seed yield per unit area (3150 kg.ha-1) was obtained with 20 cm row spacing and 50 plants. m-2. It is concluded that this planting pattern would be suitable for summer planting of safflower cv. Kooseh a local variety from Isfahan, under conditions similar to this experiment.

To study growth and yield in 19 genotypes of soybean under deficit irrigation conditions, three separate experiments were carried out-using randomized complete block design with three replications. Three irrigation regimes were applied in three experiments: Experiment 1: after 50 (optimum irrigation), Experiment 2: after 100 (moderate stress) and Experiment 3: after 150 millimeters (severe stress) evaporation from evaporation pan class A. Results showed that the Irrigation regimesgenotype interaction had significant effect on the number of seeds per unit area, oil and protein contents. Deficit irrigation had significant effect on the number of nodes, plant height, number of branches, number of pod.m-2, number of seed.m-2, grain yield, productivity index (pod weight/total dry weight), proteins and oil contents. Severe stress conditions had maximum effect on reduction in branch number, number of pods.m-2, grain yield, productivity index, oil and protein contents. Grain yield in moderate and severe stress conditions had positive and significant correlation with STI, MP, GMP indices. The highest grain yield was obtained from genotypes L11 and Clean in moderate and severe stresses conditions, respectively.