فهرست مطالب g. fathi

To study the effect of drought stress and N fertilizer application on biological yield, grain yield and yield component of three wheat cultivars, a field experiment was conducted in 2006-2007 at Shushter region in Iran. The experiment was a factorial based on completely randomized block design with replications. Treatments were wheat cultivars (Chamran, Showa and Falat), N fertilizer in two levels (50 and 150 kg/ha) and levels of drought stress (without stress, and stress at grain filling). Chamran and Falat were soft bread wheat type and Showa was durum. Results indicated that under drought stress Chamran had the higher grain yield (5584 kg/ha) as compared to Showa (5332 kg/ha) and Falat (4821 kg/ha).The high level of N increased grain yield by 45% against low level N application. Response of Chamran to N fertiliser was more than that of Showa and Falat respectively. Spike number, grain number per spike and 1000 grain weight affected grain yield.

The influence of Nitrogen (N) rates on mineral nutrient uptake in stem and seeds, proline and carbohydrate in flag leaves of Wheat (Triticum aestivum L . Var Chamran) under saline conditions was studied in a field experiment in 2003 and 2004. The experiment was conducted using a split plot design with three replications. The treatments comprised five levels of salinity: 1.5, 5, 10, 15 and 20 ds/m in main plot and three nitrogen levels: 50 , 100 and 150 kg N/ha in sub plot. Salinity treatments were applied in a clay–loam soil by water with NaCl and CaCl2 (5:1 by wt ). The results showed, the nutrient uptake was influenced by both salinity and N treatments. With the Exception of magnesium in seed, salinity increased nitrogen, calcium and magnesium concentrations in seed and stem in both years. By increasing salinity levels, the concentration of potassium in stem and seed decreased and Sodium concentration increased. In the stem the concentration of Sodium in the 20 ds/m was about 17 and 22 times more in the first and second year, respectively. In these experiments, by increasing salinity and nitrogen treatments, proline concentration in flag leaves increased in the two stages (flowering and milky stages) in both years. Salinity had similar effect on carbohydrate accumulation in both stages, but nitrogen treatment had two different effects on carohydrate concentration. In flowering stage, by increasing nitrogen application, carohydrate concentration increased but in milky stage decreased.

In order to study the effects of different waterlogging duration in growth stages ZGS11, ZGS13 and ZGS31 on root and shoot growth of three wheat genotypes Chamran, Vee/Nac and Yavaros, a pot experiment was carried out in the Ramin Agricultural and Natural Resources University in 2004. The experiment was a factorial according to a Randomized Complete Block Design with three replications. Study of root dry weight and root elongation trend showed different responses among genotypes, start of waterlogging periods and different waterlogging levels, as short period of waterlogging (10 days), had unrecoverable effects on the growth. Analysis of variance of root dry weight and root length at the anthesis and physiological maturity stages indicated significant different among all of treatments levels. Vee/Nac genotype was found superior with respect of root dry weight and root length to other genotypes. ZGS11 and ZGS31, had the highest and the lowest responses to waterlogging, respectively. Duration of 10, 20 and 30 days waterlogging at anthesis stage decreased 37.75, 44.31 and 54.01% of root dry weight, and 25.85, 47.02 and 58.88% of root length compared to control, respectively. Investigation of the root anatomy of wheat genotypes under waterlogging stress showed formation of cortical root aerenchyma as a waterlogging-resistantce mechanism.

In order to investigate the best planting time and rice cultivars for the conditions in Khuzestan Province, seven high quality cultivars of rice namely Domsiah, Binam, Ramasanali Tarom, Sang Tarom, Hasansarai, Tarom Mahalli, Daylamani and Anboori were selected and studied in 4 planting dates starting in Mid-May, with intervals of 15 days. The experiment was conducted as a split plot design in randomized complete blocks with 3 replications for 2 years from 1995 in Shavoor Agricultural Research Station. Main plots were planting dates and subplots were allocated to cultivars. Results of this experiment showed that significant differences existed among planting dates on grain yield only in the second year. Grain yields were different among cultivars in the two years of study. Simple and combined analyses indicated that there were significant interactive effects between planting dates and cultivars. Tiller number was different between planting date and cultivars in the first year. Interactive effect between planting date and cultivars on tiller number was not significant. Maximum grain number in spike obtained early June planting date (76 grains per spike) and lowest grain number in spike obtained early May planting date (28 grains). Among cultivars, Anboori with 152 and Daylamani with 17 grains had maximum and minimum grain numbers in spike, respectively. One-thousand grain weight was maximum in the early June planting date. Among cultivars, Binam and Daylamani had maximum and minimum grain weights, respectively. Highest fertility percentage was obtained in early June planting date compared to other planting dates. Fertility percentage of cultivars depended on temperature at growth stages before and at anthesis, which was early June for all cultivars. Among environmental factors affecting plant growth, temperature was relatively more important than other factors, particularly than the photoperiod. Even under Khuzestan conditions, there is a wide range of temperature levels for rice planting (from early March to early November) however, even this wide temperature range may not be enough to provide favourable conditions for planting all the cultivars.

Effects of different levels of nitrogen fertilizer and cutting time of forage on grain and forage yield of barley (Hordeum vulgare L.) Karoon cultivar was studied during 1995-1996 at Ramin Agricultural Research and Educational Center, University of Shahid Chamran, Ahwas, by using a split plot design in randomized complete block with 4 replications. Main plots were assigned to five levels of N fertilizer (45, 90, 135, 180 and 225 kg N/ha) as urea fertilizer and subplots to three cutting times (no cutting, cutting forage at early stem elongation without removing reproductive meristem and cutting forage in the middle of stem elongation with cut reproductive meristem). The effects of N rates and cutting time on grain yield were significant. Maximum yield was obtained with 281.6 g/m2 when crop plants received 90 kg N/ha and cutting time at early stem elongation and minimum yield was obtained (158.2 g/m2) with 45 kg N/ha and cutting forage in the middle of stem elongation. Interactive effect of levels of N and cutting time on spike number per m2, grain number in spike and grain weight were significant. Among yield components, spike number and grain weight showed the highest sensitivity to both. Different levels of N increased forage protein concentration and protein yield significantly, but delay in cutting time decreased protein concentration and increased protein yield. Results indicated that high levels of N could not compensate for the delay in cutting time of forage for grain yield. It was concluded that application of 90 kg N/ha and cutting time in early stem elongation was preferable for grain and forage production as compared to other treatments.

Effects of different levels of nitrogen fertilizer and cutting time of forage on grain and forage yield of barley (Hordeum vulgare L.) Karoon cultivar was studied during 1995-1996 at Ramin Agricultural Research and Educational Center, University of Shahid Chamran, Ahwas, by using a split plot design in randomized complete block with 4 replications. Main plots were assigned to five levels of N fertilizer (45, 90, 135, 180 and 225 kg N/ha) as urea fertilizer and subplots to three cutting times (no cutting, cutting forage at early stem elongation without removing reproductive meristem and cutting forage in the middle of stem elongation with cut reproductive meristem). The effects of N rates and cutting time on grain yield were significant. Maximum yield was obtained with 281.6 g/m2 when crop plants received 90 kg N/ha and cutting time at early stem elongation and minimum yield was obtained (158.2 g/m2) with 45 kg N/ha and cutting forage in the middle of stem elongation. Interactive effect of levels of N and cutting time on spike number per m2, grain number in spike and grain weight were significant. Among yield components, spike number and grain weight showed the highest sensitivity to both. Different levels of N increased forage protein concentration and protein yield significantly, but delay in cutting time decreased protein concentration and increased protein yield. Results indicated that high levels of N could not compensate for the delay in cutting time of forage for grain yield. It was concluded that application of 90 kg N/ha and cutting time in early stem elongation was preferable for grain and forage production as compared to other treatments.