Seed and Plant
Year:2005 | Volume:21 | Issue:2|Papers Count:13

In order to detemine forage production of clover speices in spring and fall plantings, an experiment was carrid out in randomaized compelet block desgin with three replications and twelve treatments in Karaj during 1999-2001.The results showed that dry matter yield mean of clover speices in three years of experiment, in autumn planting was higher than that in spring planting. The highest dry matter yield from years (1999-2001), 8.13 tha-1 and 8.67 tha-1 in spring and fall plantings respectively, belonged to persian clover cv. Alshtar. The combined analysis results showed that the effects of year, cultivar and interaction of year x cultivar for dry matter yield were significant at 5% level. The first cut in spring planting and second cut in autumn planting had the highest dry matter yields. In general, a trend of increase in dry matter yield of clover cultivars was observed from spring planting to fall planting. It was also cleared that persian clover cv. Alshtar with a mean forage yield of 8.40 tha-1, a variance of 0.77 and a coefficient of variation of 4.6, had the highest yield and most stability among the cultivars.

In order to study responses of wheat genotypes to sowing date, a study was carried out during 1998-2001 cropping season, for a three years period at Ahvaz Agricultural Research Center, using split plot experiment in a complete randomized block design with three replications. Three sowing dates (5 Nov., 6 Dec. and 11 Jan.), and four bread wheat genotypes (Star, Chamran, Dove and Fong) were assigned as main plot and sub plot, respectively. The results indicated that the genotypes responses to sowing dates were significantly different. Star in the first sowing date had the highest grain yield. Star grain yield at later sowing dates was decreased dramatically mainly due to delay in spike emergence. The Fact that grain filling period coincided with terminal heat stress, Chamran and Dove due to their phenological patterns had the highest yield in the second sowing date. Fong had low level of response to sowing date. There was a negative correlation between anthesis dates and grain growth period. This implies the sooner spike emergence, the longer grain growth period.

To determine the stability of grain weight using chemical desiccations and to sudy the gas relations in different advanced barley lines, this study was carried out during 2002-2003 growing season at Ghamloo Agricultural Research Station in Kurdistan province. A split plot with two main plots (rainfed and irrigation), 24 sub plots (different barley genotypes), with three replications was applied. Ten days after anthesis in irrigated plots, by spraying NaCLO3 0.4% on shoot organs, photosynthesis was disordered. In rainfed plots relative water content (RWC) was measured. Using IRGA, advice gas paremeters in rainfed and irrigated plots was also counted. The grain weight of all lines was reduced under spraying. There was positive and strong correlation between grain weight reduction in sprayed and rainfed conditions (r = 0.7**). Based on SSI (Stress Susceptible Index), three groups (tolerant, susceptible and medium) was indicated. Except water use effeciency, all gas parameters were reduced under rainfed, but this reduction was less in tolerant lines than those of susceptible lines. No significant difference was observed between tolerant and susceptible lines in RWC.

In order to determine the most suitable seed and seedling vigour test of hybrid maize (Zea mays L. Cv. single cross 704) by study and evaluation of seed viability and various seed and seedling vigour indices at three seed sizes(flat, medium and round) for predicting seed and seedling vigour and field performance, this study was carried out in 2000 at field and Central Seed Analysis Laboratory of Seed and Plant Improvement Institute in Karaj. In field, after planting seeds, seedlings emergence time, seedling vigour indices, seedling dry matter and height were measured and data analysis showed that flat seeds produced seedlings with high dry matter, height and field emergence. In laboratory, seeds at three sizes were tested by three vigour test of maize seed, seedling growth vigour test, complex stressing vigour test and cold test. In addition to seed viability, thirteen seed viability and seed and seedling vigour indices including mean time to germination and daily germination speed were determined. Abnormal seedling number in complex stressing vigour test were higher than those at other two vigour tests. Correlation among different indices showed that number of emerged seedlings in field had highly significant positive relation with final germination percent, mean time to germination and mean daily germination by seedling growth vigour test, daliy germination speed, mean daily germination, seedling dry weight and seedling vigour index by complex stressing vigour test and mean time to germination and daily germination speed by cold test and abnormal seedling number evaluated by complex stressing vigour test.

Phosphorus and zinc application effects on uptake of nutrients and P and Zn residuals in soil for rain-fed wheat conditions were investigated in the present study. An experiment was carried out in RCBD factorial arrangement design with four phosphorus levels (0,50,100 and 150kg P2O5ha-1) and four zinc levels (0,10,20 and 30 kg Znha-1) with three replications for three cropping seasons (1995-1998) in Dryland Agricultural Research Institute (Maragheh). The results showed that P application rates increased slightly uptake of N, P, K, Fe, Cu and B in wheat and increased significantly (P<0.01) Mn uptake, but, P application rates decreased Zn uptake upto 9% compared to control treatment. Zinc application rates increased significantly (P≤ 0.05) K, Zn and Cu uptake and increased slightly other nutrients. However, P application increased significantly (P<0.01) amount of phosphorus residual %159 in soil. Phosphorus uptake by wheat was 4% supplied P in soil. Zinc application increased significantly (P<0.01)amount of zinc residual %1015 in soil. Zn uptake by wheat was about 3% of supplied Zn in soil. It can be concluded that application of P and Zn fertilizers increases uptake of other nutrients by wheat from the soil. In addition, application ofP and Zn fertilizers increases highly P and Zn residuals in soil.

For increasing of irrigation efficiency and water use efficiency in cotton crop and decrease water wastes in usual methods of surface irrigation, this research was carried out during two years 2000 and 2001. The experiments were in randomized complete block design with three replications. In the first year treatment: I1: usual irrigation of furrows with space 70 cm, 12:Every Other Irrigation (EOI) of furrows with space 70 cm until fifth irrigation, 13: (EOI) of furrows with space 60 cm, 14:(EOI) of furrows with space 70 cm, and in the second year I1: usual irrigation of furrows with space 70 cm, 12: (EOI) of furrows with space 60 cm, 13: (EOI) of furrows (unstable) with space 70 cm, 14: (EOI) of furrows with space 60 cm until sixth irrigation and IS: (EOI) of furrows with space 70 cm were performed respectively. The results showed that, the performance of different every other irrigation methods did not affect yield components (with exception of boll number in first year). Despite the significant decreasing of water used in the whole growth period at the rates of 30.12% and 27.06% comparing with control in the first and the second years respectively, yield decreasing was not significant. In this respect, the treatments of every other irrigation were increased water use efficiency at the rates of 24.86% and 35.98% in comparing with control in the first and the second years respectively. The results in general was indicated the superiority of every other irrigation furrow with space 70 cm comparing with other treatments.

In order to determine the best weed control method in dry-farming of rapeseed and reach to optimal yield and also the best use of soil-water sources in drylands, this experiment was conducted in three years as RCBD desing in three replications at Maragheh, Dry Land Agricultural Research Station on Oilseed rape Cv. PF7045,91. The factors of trial were A1: No weed control (check), A2: One hand weeding before stem elongation, A3: Two hand weedings (one in mid of rosette and other before stem elongation), A4: Mechanical control with sweep before stem elongation, A5: Chemical control with Treflan 1.5 litha-1 before planting and A6: Chemical control with Treflon 2.5 litha-1 before planting. Combined analysis of the data showed that year effect was significant at 1%propability level on weeds per unit area, pods per plant, seeds per pod, grain yield, oil percentage and percentage of moisture lost. Only seed per pod and 1000 seed weight were affected by yearx control methods interaction. Two hand weeding streatment with 487.5 kgha-1 grain yield was arranged in class A, and chemical control by Treflan 2.5 litha-1 with 285 kgha-1 grain yield in class B. Chemical control by 2.5 litha-1 Treflan with 107 kgha-1 oil yield, arranged after two hand weeding, treatment. Over-all chemical weed control treatment by 2.5 litha-1 Treflan before planting is recommended for Maragheh region and other regions with similar climatic conditions.

Identification of virulence factors in the population of barley powdery mildew, is a necessary step for development of barley cultivars resistant to the disease in different parts of a country. In the present investigation, trap nurseries consisted of Near Isogenic Lines (NILs) of barley powdery mildew, were grown in ten different regions of Iran under natural infection during 2000-2002. Data on disease severity and responses of NILs were taken according to Saari and Prescott (1975) method modified by Eyal et al. (1987). According to the results, the virulence frequencies of Blumeria graminis f.sp. hordei varied in different locations and years. Virulence on Mlk was most freguent in all locations, followed by Ml(La), Mla9 and Mlal8 respectively. Virulence on Ml-Spiti were observed only in Ahvaz and Dezful, and virulence on Mla17 were recorded with the lowest frequency in Minoodasht. Virulence on Mlk, Mla9 and Ml(La) appeared to be common in all regions. No virulence on Mla6, Mlg+MlCP, Mlp, Mla7+ MlAb, Mla3, Mla19, mlo, Mla13, Mla16, and Mla19 were detected.

In order to evaluate the effects of various seedbed preparation methods on grain yield of corn and some soil properties, an experiment was conducted at Agricultural Research Station of Orzoiyeh, in Kerman in 2000 and 2001. Two residues management treatments (burned and nonbumed) along with three tillage systems (moldboard plow, disk and minimum tillage) were laid out in a strip plot within a randomized complete block design with four replications. Disk and moldboard plow treatments had the highest grain yield and plant height, respectively. Disk, moldboard plow and minimum tillage treatments produced grain yield of 15.29, 14.87 and 12.45 tonha-I and plant height 198.6, 192.6 and 185.6cm, respectively. At the harvesting time, organic carbon, potassium and phosphorus of soil and kernel protein in minimum tillage treatment was higher than those in other treatments. Residues management treatment has not significant effects on each traits, but grain yield, 1000 kernel weight, kernel protein and organic carbon was higher in unburned residue treatment. Disk with 15.96 tonha-1 and moldboard plow with 14.94 tonha-1 in combination with unburned residues treatment had higher grain yield. Based on the results of this study, incorporating residues with disk might be more adventageous under the conditions similar to those in this experiment, if the sowing machine be able to seeding corn precisely under minimum tillage condition.

Stripe rust is the most important disease in most wheat growing regions in Iran. In 2002-03 and 2003-04 cropping seasons, 9 lines and cultivars received from ICARDA germplasm, which carry combinations of adult plant resistance genes of yellow rust and leaf rust together with Bolani cultivar as susceptible check were tested in seedling and adult plant stages. In the seedling test, pathotype 134E134A+ was used in the greenhouse condotions. For inoculation, urediniospores were mixed with talcum powder (1:4). After inoculation the seedlings were placed in an incubation room at 10°C and 100% RH for 24 h in the dark. Incubated plants were moved to greenhouse with a temperature of 18°C. Infection types were recorded 14-18 days after inoculation using the scale described by McNeal et al. (1971). Infection types equal or higher than 7 were considered as virulence and infection types less than 7 as avirulent. In the field in Karaj, all 10genotypes were planted in two rows of one-meter length with 30cm distance and were artificially inoculated with race 134E134A+of stripe rust. The susceptible wheat cultivar (Bolani) was planted as spreader around the field and between the rows. Field assessments were based on disease severity according to the modified Cobb scale (Peterson et al., 1948)and disease reaction (Roelfs et al., 1992). In the seedling test all genotypes were susceptible. In field, all genotypes were resistant or moderately susceptible except Japateco S and Bolani. Pawon76 with Yr29 gene showed 80MS response. Cultivar Pastor (Yr31 + 3 minor genes) was resistant (JOR). Yr18 gene indifferent line/cultivar showed moderately susceptible response (80MS), but in Opata85 the response of this gene in combination with 3 more minor genes was reduced to 5R. Use of link genes such as Yr18 and Lr34 with combination of other genes to the leaf rust and stripe rust is the best strategy of diseases control. There is the chance to use these resistant genotypes directly or as resistant source for breeding program.