CROP PHYSIOLOGY
Year:2011 | Volume:3 | Issue:10|Papers Count:11

In order to analysis of traits path effective on grain yield of maize hybrid SC.704 under Irrigation-off at growth stages, pattern and plant density in the climate of Ahvaz, an experiment was performed by using split split plots in the form of complete randomized block design with three replications, in the summer between 1386 and 1387 years. Irrigation-off at different growth stages as the main treatment with four levels of irrigation-off in eight leaf stage (S1), irrigation-off in twelve leaf stage (S2), irrigation-off in male florescence appearance stage (S3) and full irrigation (S4) in the main plots, planting pattern with two-level pattern of a row and two rows (zigzag) in the sub plots, and plant density as the sub-sub treatment with three levels of density D1=75000, D2=85000and D3=95000 plants per hectare were placed in sub-sub treatments. Path analysis results showed that the most direct effect on increasing grain yield per unit area, was related to: the number of grain per unit area, with 9.78, the number of grains per corn with 6.03 and thousand grain weight with 3.7, respectively. The indirect effect of high grain number per unit area on grain yield through indirect effects of grain number in a row, the number of grain in corn, biological yield and harvest index to increase grain number per unit area can be justified. The number of grains in corn; also is indirectly effected by grain number in a row, the number of grains per unit area, biological yield and harvest index of the second mentioned indirect effect on grain yield that seems increased biological yield through providing suitable conditions for the entry 0f plant into the reproductive stage affects grain number per unit area and the number of grain per corn, indirectly, has been increased the grain yield per unit area in this experiment. Stepwise regression results and dependent traits showed that 99.86 percent grain yield changes effected by biological yield and harvest index was explained. The role of biological yield with the 97.98 percent ratio on increasing grain yield reflects the effect of this factor on increasing yield grain. Similarity in cluster analysis of grain traits, the number of grains in a row, the number of grains per corn with 99.76 percent and biological yield with grain yield with99.52 percent similarity showed the highest uniformity in changing traits in this experiment.

One of the ways to improve crop, is the use of micro-nutrients. Zink is one of the most important micro-nutrients and its deficiency is seen in Iran. By spraying we can give these micro-nutrients to the plant in the fastest time and reduce the use of chemical fertilizers. In order to study the effect of spraying zinc sulfate on Soybean, a factorial experiment was made during 2009 at Islamic Azad University Research Farm at Khorramabad Region. This factorial experiment was done by using a randomized complete blocks design with four repetitions. The first factor is soybean varieties in three levels: V1=m7, V2=m9, V3=L17 and the second factor is zinc sulfate solution spray in three levels of Z2=0, 0.002 and Z3=0.004 kg/L, Z1=0 applied at flowering and pod stages. The characteristics under study in this research were: seed yield, seed oil percent, seed protein percent, plant height and the number of pod per plant. The results show that seed yield is independent from zinc sulfate spraying and the highest seed yield (2130.9 kg /ha) was obtained from L17 variety. The interaction between zinc sulfate solution spray and variety was only significant on protein and seed oil percent (p-value<0.01). The study results showed that there is negative and significant correlation between seed oil percent with seed protein percent (r=-0.725**).The number of pod per plant was under influence of zinc sulfate and increased. The influence of under study factors on plant height was not significant. Also positive and significant correlation was not observed between seed yield and measured yield components. The highest protein was obtained from L17 with average of 55/41% and the highest oil was obtained from m9 with average 35/21%. According to the results, L17 variety had the best yield and 0.002 Kg/L spraying, was considered as the most appropriate level.

This research was conducted in Pashminehzar region of Andimeshk city in 2009-10 in order to study the effect of canola planting pattern and its varieties as a tool in the sustainable management of weeds of canola varieties. This research was in the form of strip split blocks in the base of complete random blocks with 4 repetitions consisting of planting pattern treatment in 3 levels (95 cm furrows +2 swing lines and surface swing) as the main factor and 4 canola varieties (Hyola 401, Hyola 308, Hyola 4815 and Hyola 50) as sub factor. Canola and weeds dry matter was measured respectively at 2 and 3 stages during the experiment. The obtained results from variance analysis showed that planting pattern treatment and canola varieties had a significant effect on weeds dry matter before and after flowering, during canola physiological maturity, seed yield and harvest index (HI) in 1 % level. General evaluation of the results showed that Hyola 401 variety in 95cm furrows +4 sowing lines planting pattern, had a higher genetic vigor for seed yield and more adaptability as well as more effective control and better competition with weeds. So, using the mentioned variety and planting pattern can be suggested as an effective factor in the cultural management of canola for the natural weed control and higher seed production.

In order to evaluate the spacing between rows, planting density and pattern in corn silage (S.c.704) in the second cultivation after rice harvest, a factorial experiment in the form of a random complete blocks design with four repetitions at the Agricultural Research Center of Ghaemshahr City (Station Qrakheil crops farming) was conducted in 2009. Intervals between treatments consisted of three rows (85, 75, 65 cm), plant density (70 and 80 thousand plants per hectare) and planting pattern (single row and double rows zigzag), respectively. The test results showed that the highest leaf dry weight density per hectare under 80 thousand plants per hectare and the maximum percentage of sugar (WSC) in the density of 70 thousand plants per hectare was achieved that it was about 11 percent more than density of 80 thousand plants per hectare. The most dry weight of leaf, stem and ear in hectare under cultivation was in zigzag double rows, that respectively 12, 23 and 34 percent was more than linear single-row planting. Also, the maximum and minimum levels of quality traits including productive dry matter (DMD), protein (CP), fiber (ADF) and ash (ASH), respectively under cultivation of two zigzag rows and linear single row was obtained. Dry performance with all indicators of quality had a very high and positive correlation probably due to delayed planting of summer (the first week of September).

Seed deterioration is very common phenomenon in storing seeds. The Higher temperature and humidity, the more deterioration is expected. Seed priming is known as a effective seed treatment which could improve percentage of germination, germination rate and seedling length in many species. In order to investigate effect of hormone priming on deterirorated maize seeds, a factorial experiment was conducted with four replications. Treatments where five gibberlline concentration (50, 100, 200, 400 and 800 ppm) time of seed priming (8, 12 and 24 hour) and accelerated ageing duration (4, 7 and 14 days). Seed germination and germination rate decreased due to higher duration of accelerated ageing treatment. Root length, shoot length also significantly decreased by increasing duration of ageing. The most effective treatments were application of 100 and 400 ppm of gibbelline for 12 hour which significantly increased germination percentage and germination rate. Gibberlline significantly improved seedling length of deteriorated seeds. According to our result, application of 100 ppm gibberlline for 12 hour could significantly improve germination characteristics in deteriorated seeds of maize. Germination percentage of aged seeds increased around 20% while germination rate was improved around 65% by application of hormone priming with 100ppm GA3 and 12hour of duration. So it is suggested that hormone priming could be known as an applicable treatment for improve aged seeds in corn and it could increase the germination potential for aged seeds.

In order to study the effects of planting density and nitrogen fertilizer on the yield of medicinal plant Aloe barbadensis, an experiment was done as factorial in the form of base design of complete random blocks in three repetitions in Mazandaran province, Noshahr city in Katy village in the land area of 450) m2 ) in 1388. The levels of density include 2, 4, 6 plants in m2 and the levels of nitrogen (urea fertilizer 46% net nitrogen) include 50, 100 and 150 kg/hectare. The results showed that nitrogen and density levels have significant statistical effect on the studied characteristics. Among the performance attributes, the most performance of leaf weight, gel weight, and total weight of plant with average 3479/133, 1994/433, 3572/050 g/ m2 in the level unit in treatment 150kg/hectare nitrogen fertilizer and density of 4 plants in m2 and the most the performance of the number of leaf and the number of sucker with average 18/627 and 4/503 in treatment 150kg nitrogen fertilizer and density of 6 plants in m2 were obtained. Since in plant Aleo vera the gel amount is very important for us, so regarding to the climatic conditions of research, in treatment N3D2 (nitrogen fertilizer: 150kg/hectare, and 4 plants in m², the most weight of gel was obtained.

So far the main part of agriculture researcheshas been based on the field experiments and regression analysis. The great disadvantage of theseresearching methods is the impossibility of recognizing the system operation process and generalizing the obtained results out of limit at the experiment. But by helpingmodeling, the possibility of simulation and knowing the system production processes under a series of determined conditions, will be prepared and studied. This research was done in order to study the water movement in the soil and its simulation by LEACHN model in variable humidity conditions of soil under Chamran wheat culture. Three irrigation treatmentswere under the name of I1 (without water stress), I2 (water irrigation interrupting on cluster appearance stage) and I3 (water irrigation interrupted on wheat grain latency), and five proportions of nitrogen with 0, 40, 80, 120, 160 kg/hectare. In this study the water movement process in the soil was simulated by LEACHN model. As the LEACHN model has been used to corn at the beginning, by using SUCROS model and the results of past researches, the wheat root growth equation was obtained and then used in LEACHN model. The measurement of field humidity and its comparison with the results of humidity estimation, explains a high correlation between model and field results. The model predicted the field humidity with high precision. After calibration and model validation experiment, the study on percentage of water absorbed by plant showed that the most transpiration and/or water absorption got result on 10 to 20 centimeter layers. This indicates the importance of the surface layers in water stress conditions. The model has shown that the transpiration amount was proportional with water filling in each treatment. The water balance sheet examination profile soil shown that on the first growth season, the used main water evaporates from the soil surfaceand by passing time and increasing the leaf area index (LAI), the most amount of transpiration and evaporation will be in the form of transpiration.

In order to study the phonological stages and grain yield of mid maturity wheat genotypes in response to different growth degree - day (GDD) accumulation, this field research was carried out in split plots experiment using randomized complete blocks design with three repetitions at Agricultural Research Station in Ahvaz in 2008-2009 cropping season. Main plot was consisted of three planting date including Nov.11, Nov.21 and Des.1 and sub plot was including 10 mid maturity wheat genotypes consisted of chamran cultivar and lines: S-80-18, S-83-3, S-83-4, S-84-14, SS-83-3and D-79-15DH-86-12, DH-86-15, DH -86-17. The results showed that the planting date effect was significant for growth degree-day accumulation (GDD) from planting date to booting, heading, pollination, and physiological maturity. Genotypes difference and interaction of planting date and genotype were significant for mentioned traits. The highest and the lowest growth degree-day from planting to booting, heading, pollination and physiological maturity were obtained on Nov.11 and Nov.21, respectively. The effect of planting date was significant for grain yield, biological yield and harvest index. The highest grain yield with an average 5260 kg.ha-1 belonged to Nov.11 planting date. Among genotypes, the highest grain yield obtained from line DH-86-15 with 5411 kg.ha-1. In interaction of planting date and genotype study, thehighest grain yield with 5739 kg.ha-1 was obtained from line: DH-86-15 in the first planting date. In attention to the significant correlation of grain yield with Growth degree -day (GDD) accumulation, it seems that the regulation of planting date to collect the thermal unit is very important for completing growth and development stages.