نشریه یافته های نوین کشاورزی
سال نهم شماره 2 (پیاپی 34، زمستان 1393)

Drought is an abiotic stress that restrict water for agriculture. This experiment was conducted with irrigation factor at two levels includes {a1: Control, a2: cut irrigation after flowering stage} and the second experimental treatments at five levels includes{b1: control, b2: seed inoculated with bacteria (Azospirillum, Azotobacter, Pseudomonas), b3: seed inoculated with bacteria (Azospirillum, Azotobacter, Pseudomonas) and sprayed silicic acids, b4: seed inoculated with bacteria (Azospirillum, Azotobacter, Pseudomonase) and sprayed amino acids, b5: seed inoculated with bacteria (Azospirillum, Azotobacter، Pseudomonas) and sprayed silicic acids with amino acids} in randomized complete blocks design with four replicates using analysis of split plot. Results showed that drought stress reduced the traits measured, but seed inoculated with plant growth promoting bacteria, sprayed silicic acid and amino acids in normal irrigation and drought stress conditions increased seed 1000 weight, spike length, number of spikelet per spike, number of seeds per spike, biological yield and seed yield. Also seed inoculated with plant growth promoting bacteria and combined silicic acid and amino acid application increased seed yield in normal irrigation and drought stress about %27/76 and %44/64, respectively.

The main cold damage occurs in germination and seedling growth stages. To examine the effect of cold stress effects on rice seedling growth was carried out a greenhouse experiments in Deputy of Rice Research Institute in Mazandaran (Amol) since 2010. The basic design was conducted a completely randomized with split plot factorial experiment in 3 replicates with different temperature levels (10, 13, 16, 32 ° C) and its duration (1, 2, 3, 4, 5 days) on five varieties of rice (Dialam, line 843, Tarom, Fajr, Shiroudi). The varieties were designed as main plot and and temperature levels and duration of thermal treatment in sub-plot. The seedlings were placed in normal growth conditions until the 3-2 leaf stage seedlings age (12-8 days) and then transferred to a growth chamber and were treated at 10, 13, 16 ° C for 1, 2, 3, 4 and 5 day. After the treatment, four seedlings from each replicate were selected and growth characters such as height, seedling dry weight (dry weight of shoot + root), sensitivity index, leaf area and color were measured. Results showed that among the varieties, the stress intensity, stress duration and their interaction effects were a significant probability of 1% for all traits in the seedling stage in which reflects the severity and duration of cold stress on the varieties is discussed. Low temperatures were reduced, the growth rate of seedlings up to 10 -50% compared with control treatment. Low temperatures (10 oc) were decreased new roots production and seedling dry weight in which 60% reduction compared to 32oc treatment. Temperature was caused discoloration of lamina and the color of the leaves of rice seedlings after exposure to cold stress conditions could be concluded, each variety is greener leaf color of seedlings with less damage and is more tolerant to cold. Tarom and Shiroudi varieties compared to other varieties more tolerant to cold stress, however, Fajr variety was more sensitive.

In order to determine the best date of transplanting and plant density on yield of rice Fajr cultivar an experiment was carried out at split plot in Randomized Complete Block Design with four replications in 2009 in experimental field of Islamic Azad University of Chaloos. The dates of planting in 3 levels (30May, 9June and 19June) as main factor and planting density in four levels (17, 34, 51, 68, plant.m 2) were considered as sub-factor. The results showed that a grain yield and harvest index 12.2 and 24.7 percent decrease. Grain yield with increase planting density until 68 plants. 10.3 percent increase because, the number of empty grain in spike 22.5 percent decries and the number of grain and number of spike plant. 50 and 52.1 percent increase. The number of whole grain with planting density on the number of empty grain and on grain yield and biological yield in level of (%5 and 1%)., Highest yield grain for planting date June 9th with planting density 34 plants.m2 obtained.

Drought stress is one of the most important factors limiting maize growth and yield in world; which maize hybrids differently respond to drought stress. Growth stages, also, have different sensitivity to drought stress. In order to examine the effect of drought stress in different growth stage on growth, yield and yield components of five maize hybrids, a study was conducted as a completely randomized design, at 2014. The first factor was drought stress (without stress, stress at 8 leaf, tassel emergence, kernel filling), and the second factor was maize hybrids (singe crosses 704, 500, 524, 400 and 370).The results showed that most reduction due to drought stress on grain yield was in tassel emergence and kernel filling, on thousand grain weight was in kernel filling, on grain number in ear was tassel emergence and on days to physiologic rapping was in 8 leaf. Furthermore, 704 hybrid had the highest yield, grain number in ear and days to rapping; 400 hybrid also had the highest thousand grain weight. On average, drought stress decreased grain yield by 36.70%. The finding of this research indicated that although drought stress in all growth stages decreased growth and yield and but for prevent economic loss must avoid drought stress; however in limited irrigation resources conditions, with a slight decrease in yield the saved water might be used for other crops.

There is noticeable insoluble phosphorus in the soil and some of bacterium have not capability of release insoluble phosphorus. Today, the lack of this element have compensate with use of chemical Fertilizer, chemical fertilizer have harmful effect on the bioenvironmental and decrease quality of agriculture production. Literally in nowadays for developing sustainable agriculture execute system with sufficient form inputs with integrated usage of chemical fertilizer and bio fertilizer specially bio fertilizer as a effective solution for replacing Agriculture for produce crop and keeping yield crop in a acceptable level. This study had performed in order to; study the effect of the release Phosphate-solubilizing bacteria on Hyssopus officinalis L. This experiment performed in the randomized complete blocks base design as a factorial with three frequencies. Two level Phosphate-solubilizing bacteria (PS1: use Phosphate-solubilizing bacteria), (PS0: no use Phosphate-solubilizing bacteria) and five level (P0: 0kg/h pure P2O5), (P90: 90 kg/h pure P2O5) (p115: 115 kg/h pure P2O5), (P140:140 kg/h pure P2O5), (P165:165 kg/h pure P2O5). In this research used Triple phosphate super as phosphate fertilizer and Baver2 as Phosphate-solubilizing bacteria.This research had performed in Arak in year 1388. The results of this experiment showed that, the mixture of biologic phosphorus and Triple phosphate super, Characteristic. plant height, flower branch height, the number of flower branch,percent of essential oil, yield of essential oil per hectare, noticeable increase with application phosphorus fertilizer treatment as compared with non-phosphorus fertilizer treatment.Almost use of 90 Kg/h with Phosphate-solubilizing bacteria was best in total Characteristic. Interaction between phosphorus and Phosphate-solubilizing bacteria all of characteristic was signification. it can be concluded that, we can reduce phosphorus fertilizer to 50% in the seeds yield, by using release bacteria, without any significant reduction.

In order to investigate irrigation intervals effect of irrigation intervals, manure and zeolite traits of agronomical and yield of potato varieties Agria on experiment was conducted in moradi field in 5km Arak-Farahan in 2010. The exprimental design was split plat on randomized complete block design with four replications. The treatment applied, including irrigation at three levels 6 days, 8 days and 10 days as main plot and in sub plots treated manure and zeolite four levels include: control (no use of manure and zeolite), 20 ton/ha of manure + 4 ton/ha of zeolite, 40 ton/ha manure and 8 ton/ha zeolite. The results showed that application of manure and zeolite on traits of measured at 1% level of probability was significant.with increasing of irrigation in terval from 6 to 8 day, yield reduced by 7/19 % declined. Main effects of manure and zeolite showed the highest tuber yield equivalent of 59/88 ton/ha from 20 ton/ha manure +4 ton/ha zeolite was obtained. Effect of interaction showed that the highest tuber mean total yield equivalent product 63/6 ton/ha from irrigation six days and application 20 ton/ha manure+4 ton/ha zeolite was obtained that with tretmant of irrigation interval 8 day and application along with 20 ton/ha manure+4ton/ha zeolite was not significantly.