Iranian Journal of Crop Sciences
Year:2005 | Volume:7 | Issue:3|Papers Count:10

In order to study the effects of sowing date on grain and oil yield, and yield components of four canola genotypes, an experiment was conducted at Agricultural Research Station of Gonbad during 2002–2004 cropping seasons. The experimental design was a split plot arranged in a RCBD with 4 replications. Four sowing dates (Nov. 5, Nov. 20, Dec. 5 and Dec. 20) were assigned to main plots and four genotypes (Hyola 401, S-3, Quantum and Option 500) were randomized to subplots. The number of days from emergence to physiological maturity, the number of pod per plant and 1000-grain weight in first year of study was significantly greator than those in second year, because of cooler temperature in the first year. However the effect of year on grain yield was not significant. The combined analysis of variance showed that there wasn’t any significant difference between the grain yields of two first sowing dates. The grain yield of first, second, third and fourth sowing date were 3417, 3431, 2945 and 2358 kg/ha, respectively. Hyola 401 Hybrid had the highest grain yield, due to the greatest number of pod per plant and 1000-grain weight. The mean grain yield of Hyola 401, S-3, Quantum and Option 500 genotypes were 3457,2863, 2763 and 3068 kg/ha, respectively. The oil percent in the first year of study was greater than second year. The oil content in fourth date sowing was also greater than the others, which could be associated with the heat stress at physiological maturity. Hyola 401 hybrid and Option 500 genotypes are recommend for sowing in Nov. 5-20.

Microsattalite markers are genome specific, co-dominant and highly polymorphic markers with known map location. These markers are very suitable for quantitative trait loci mapping. In order to identify the molecular markers linked to cold resistance genes in rapeseed, a F2:3 derived population from crossing between cv. SLMO46 (winter type and cold resistant) and cv. Quantum (spring type and susceptible to low temperature) were evaluated using microsatellite markers. The LT50 (the temperature in which 50 % of plants are killed), as a cold resistance index in F3 families was measured. The parental polymorphism was assessed using 350 SSR primer pairs. The 32 polymorphic primer pairs were selected for genotyping of F2 individuals. Linkage map was constructed using polymorphic markers. The markers were assigned to five linkage groups. The relationship between LT50 and genotypic data was analysed using single marker analysis, interval mapping and composite interval mapping methods. Three detected QTLs explained 13 % of the LT50 phenotypic variations.

Two experiments were conducted in order to evaluate reaction of summer safflower to different of intensities drought stress at Isfahan region. Three lines of safflower selected from Isfahan land race (Isfahan-8, Isfahan-22 and Isfahan– 44) were planted at three densities (31, 20 and 13.3 pm-2) under four irrigation regimes (after 70, 140 and 210 milimeters evaporation from calss A pan until maturity and after 140 milimeters evaporation untill  full flowering). Planting was done in north- west of Isfahan uzing a rondomized complete block design with a split-split plot layout and three replications during 2001 and 2002. The effects of drought stress on some characteristics including plant height, branching height, number of secondry-branch per plant, number of heads per plant, LAI, total CGR, NAR, flower yield, grain yield, oil yield and HI were studied. The results showed that decreased water supply in safflower canopy caused an intensive stress in canopy. Drought- stress in both years, decreased significantly all characteristics under study except NAR and HI that were increased.In both  years, at the first level of drought stress, (Irrigation after 140 milimeter evaporation until maturity), the reaction of safflower to drought stress was considerable, however with increase in drought stress intentsity, reaction of safflower to stress decreased. Therefore, it could be concluded that safflower requires adequate water for optimun growth and production this plant adapts to deficient water conditions.

The effects of 0,30,60,90 and 120 Kg N/ha and 0,100,200 or 300 Kg K2O/ha on growth, grain yield, yield components of transplanted rice cv. Khazar were investigated in a field trial in 2001 crapping system at the Rice Research Institute, Rasht, Iran. Results showed that increasing rates of nitrogen fertilizer, increased plant height, tiller number per square meter and panicle length. Yield response to applied nitrogen fertilizer was significant up to 60 Kg N/ha. Grain yield was not affected by potassium fertilizer. However, the highest yield was obtained from 60 kg N/ha + 300 kg K2O/ha. Total dry matter increased as nitrogen rate increased up to 60 kg N/ha. Potassium fertilizer did not affect the total dry matter production. Nitrogen and potassium effect on the harvest index (HI) was not significant. Increasing the rates of nitrogen from 0 to 120 kg/ha increased the number of rice panicles per square meter. Potassium fertilizer did not have significant effect on panicles/m2. Spikelets per panicle increased by nitrogen and potassium and was greatest at 120 kg N/ha + 300 kg K2O/ha. Percentage of filled grains was affected by nitrogen and potassium fertilizers. Thousand grain weight was not affected by nitrogen and potassium fertilizer. Grain yield correlated positively with panicle number/m2 and spikelet per panicle. Nitrogen fertilizer had significant effect on Leaf Area Index (LAI) but potassium did not affect LAI significantly. Crop Growth Rate (CGR) and Net Assimilation Rate (NAR) were affected by both nitrogen and potassium fertilizers.

In order to study effects of planting date and seed rate on forage yield and morphological traits of persian clover, a field experiment was conducted to compare there factors in traditional and mechanized farming systems in 2002- 2003 cropping seasons. The experiment was carried out using split split plot in a compelet randomized block design (CRBD) with 27 treatment and three replications in SPII field experiment station, Karaj, Iran. Three planting methods (a1, a2 and a3), three planting dates (b1, b2 and b3) and three seed rates (c1, c2 and c3) were assigned as main plots, sub plots and sub sub plots. The results indicated that the biological yield and morphological traits were significantly different over years, and different cuts. The traditional farming system with 13.42 t/ha, 5 september planting date with 12.02 t/h and 15 kg/ha seed rate with 10.11 t/ha had the highest biological yield. The interaction of the traditional farming system´5 Sep. Planting date ´10 kg/ha seed rate with 16.68 t/ha of biological yield was the best combination. The combined analysis of variance showed that there was a significant effect of year on biological yield. It can be concluded that the traditional farming system, 5 Sep. and 10-15 Kg/ha seed rate is recommended for forage production.

 To study the effects of salinity and drought stresses on quality traits, 10 spring bread wheat varieties (with the names of Shole, Khazar, Arvand, Falat, Kavir, Mahuti, kallek Afghani, Roshan, Bafgi, and Bolani) were grown in experimental field station of Agricultural and Natural Resources Research Center of Western Azerbaijan province (Miyandoab) under three conditions (normal, drought and salinity stresses) in 2001-2002 cropping seasons. Experimental design was randomized complete block with three replications. Results of combined analysis of variance showed that genotypes were significantly different for most of the traits. The values of gluten index and glutenin were decreased under drought and salinity stresses. However, protein percentage, gliadin, hardness index, falling number and water absorption were increased. Arvand and Khazar with high grain yield under salinity and drought stresses, respectively (416g/m2 and 418g/m2) had the lowest gluten index; in contrast Falat had the greatest gluten index under drought stress. Tolerant varieties (Arvand and Khazar) had lower accumulation of glutenin and higher accumulation of gliadin. Kavir and Roshan that had the highest and the lowest values of grain yield under normal condition had low and high values of gluten index, under drought and salinity conditions, respectively. Under salinity and drought stresses conditions gluten index were decreased 36 percent and 42 percent, respectively. Falat and Roshan had higher gluten index than Bulani and Shole. Falat had lower values of Falling number than Arvand and Khazar. Among the varieties, Arvand with softer texture showed the least starch damage, so lower water absorption capacity.

In this investigation, genetic diversity of 35 ‘Sardari’ derivative wheat lines was studied using 60 microsatellite markers. Molecular analyses results showed the numbers of observed alleles and polymorphic information contents of each locus varied from 2 to 6 and 0.11 to 0.83, respectively. Cluster and discriminant analyses results separated the lines into 5 groups with different genetic distances. The results of this study confirmed remarkable genetic diversity among Sardari derivative wheat lines. The utilization of morphological and molecular analyses can be used for appropriate parental selection in breeding and seed increasing programs.