JOURNAL OF CROP PRODUCTION RESEARCH (ENVIRONMENTAL STRESSES IN PLANT SCIENCES)
Year:2011 | Volume:2 | Issue:4|Papers Count:8

In order to evaluate rice genotypes for tolerance to drought stress and identifying tolerant and sensitive genotypes to drought, 15 rice cultivars were evaluated according to the factorial design in the basis of randomized completely design in four replications according to non –stress conditions, drought stress in vegetative stages and drought stress in reproductive stages .Six drought resistance indices including Means Productivity(MP), Geometry Mean Productivity (GMP), Harmonic Means Index (HarM) , Stress Tolerance Index (STI), Stress Susceptibility Index (SSI) and Tolerance (TOL) were assessed on basis of seed yield. Stress intensity in this experiment for vegetative stress was (SI=0.63) and for reproductive stress was (SI=0.61). Mean comparison of genotypes showed that Dorfak cultivar was better cultivar for planting in vegetative stress and Mohammadi cultivar was better cultivar for planting in reproductive stress. Relationship between drought resistance indices and seed yield in stress and non –stress environments showed that GMP, MP, STI and HM indices were the best indices for identifying resistance and or tolerant genotypes to drought stress in vegetative stage, and MP was as the best index for identifying resistance and or tolerant genotypes to drought stress in reproductive stage in rice cultivars.

Knapweed (Acroptilon repens L.) is a highly competitive weed in the family of sunflower (Asteraceae). Using systemic chemicals is one of the most important methods to control perennial weeds such as Russian knapweed. This study (during 2005-2006) was performed in experimental greenhouse of Agriculture, Medicine and Industrial Research School of Nuclear Technology of Karaj. Experiments were conducted to examine the influence of Russian knapweed growth stage on 2, 4-D and Glyphosate absorption and translocation. Russian knapweed plants were inoculated with 14 C-2, 4-D and 14 C-glyphosate with activity of 0.080 and 0.085 micro curi (in each 10 ml of solution) in rosette, bud and bloom growth stages. This experiment was arranged as factorial with four replications in a randomized complete block design with four replications. Factors were herbicide (2,4-D and glyphosate) and Russian knapweed growth stage (rosette, bud and bloom stages). Extraction and counting of labeled herbicide (After 168 hours) showed that, there was no significant difference between translocated amount of 2, 4-D and glyphosate. But, Root accumulation of 14 C-2,4-D by Russian knapweed was greater in rosette stage, and root accumulation of 14 C-Glyphosate was greater in bud and bloom stages. Results of this study showed that root accumulation of 2, 4-D and glyphosate are directly dependent to ability of Russian knapweed control. It is expected that the best application time to chemical control of Russian knapweed by 2, 4-D and glyphosate is at rosette and bloom stages, respectively.

In order to study the effects of phosphate and sulfur solubilizating microorganisms and zinc foliar application on yield, oil and protein percentage and nutrients uptake in soybean (Glycine max L.) cultivar TMS, a field experiment was conducted in summer 2010 in Aleshtar, Lorestan, Iran on a calcareous clay loam soil. The treatments were arranged in a factorial design based on randomized complete blocks design (RCBD) with 3 replications. The treatments included: 1- inoculation with Pseudomonas fluarescens, 2- inoculation with Thiobacillus thiooxidanc, 3- inoculation with Pseudomonas fluarescens + inoculation with Thiobacillus thiooxidanc, 4- zinc foliar application, 5- inoculation with Pseudomonas fluarescens + zinc foliar application, 6– inoculation with Thiobacillus thiooxidanc + zinc foliar application, 7– inoculation with Pseudomonas fluarescens + inoculation with Thiobacillus thiooxidanc + zinc foliar application and 8– no treatment . The results of comparison showed the highest grain yield with 4133.2 kg per hectare obtained in T3 (Pseudomonas fluarescens + Thiobacillus thiooxidanc) and the highest oil percentage with 21.26% obtained in T7 (Pseudomonas fluarescens + Thiobacillus thiooxidanc + zinc foliar application).

In order to study the effect of spraying micronutrient elements on yield and yield components in grain sorghum (Sorghum bicolor), an experiment was carried out in split plot based on RCBD with three replications in 2007 in agricultural research institute of Jahadeh-keshvarzi organization in khoy. The used fertilizer in 5 levels (T1: absence of fertilizer usage, T2: spraying zinc, T3: spraying zinc + iron, T4: spraying zinc + iron + manganese and T5; spraying zinc + iron + manganese+ copper) and grain sorghum vaierties, Kimia and Sepideh were as main plots and sub plots, respectively. Duncan's mean comparsion indicated that the highest grain yeild is for variety Sepideh (12.36 T/ha). The used fertilizer was also significant for some factors, such as, panicle length, number of grain per panicle, 1000 grain weight, grain yield and biolojhical yield. The highest grain yield (14.16 T/ha) was obtained by spraying iron + zinc + manganese + copper that had 34.4 % higher than control traetment. Two factors interaction effect hadnt significantly effect on all of masuerd characters.

Due to study the effect of planting density and barley - chickpea mixed culture ratios on yield and yield component of barley this researcht was done as one year dry land farming form in boroujerd Agricultural Research Station, during 2009-2010. This study carried out as factorial experiment in the basis of randomized complete blocks design with four replications. The experimental factors contains, mixed cropping with 4 levels (M1= 100%barley, M2= 75%barley + 25%chickpea, M3= 50% barley + 50% chickpea, M4= 25% barley + 75% chickpea, M5= 100% chickpea) and crop density with 3 levels (D1=min, D2=normal and D3=max). The Results showed that seed number in spike, 1000 seed weight, seed yield, biological yield affected by plant density. The effect of mix culture ratio on spike number in plant, seed number in spike and biological yield vere significant difference at 1% level of probability. The plant density 300 seed/m2 and pure stand barley gained to maximum grain yield of barley 837.6 kg/ha and 854.8kg/ha respectively.

In order to study the effect of drought stress on morphological traits, yield and yield components of 34 hybrids of corn and influential traits on it’s yield, an experiment was carried out based on a completely randomized block design with three replication under normal irrigation and drought stress conditions in khorasan razavi agricultural research and natural resources institute mashhad, Iran in 2010. The results a variance analysis showed that in both conditions there was significant difference between all hybrids for all traits. Results means comparison of hybrids with Duncan’s multiple range test showed that in normal irrigation condition S.C500 hybrid and in stress condition N.11 hybrid had the highest yield (13.79 and 5.69 respectively). This experiment showed that kernel number per row has the highest correlation with yield in drought stress condition, wheras in normal irrigation condition ear diameter had the highest correlation with yield. In drought stress condition ear weight and 300 kernel weights had highest and lowest direct effect on yield respectively. Also the highest negative indirect effect on yield belonged to kernel number per row through ear length.

In order to investigate the effect of ascorbate and gibberellic acid on some biochemical traits in davian dragonhead (Dracocephalum moldavica L.) under drought stress conditions, an experiment was done as factorial experiment in the basis of completely randomized with four replications, irrigation in three level include without stress (FC), moderate stress (2/3FC) and severe stress (1/3 FC), ascorbate operating in two levels (0 and 10mmol) and gibberellic acid in two levels (0and 100mmol) were considered. During testing, Biochemical traits such as proline accumulation, whole carbohydrate, protein and Hill reaction were measured. The Results showed that, ascorbic acid treatment had positive and significant effect on measured traits of moldavian dragonhead under stress condition. The plant with osmotic regulation mechanism and increasing of proline (87.62mmol/L) and whole carbohydrate, to a degree tolerate stress condition. This result indicated that, ascorbic acid and gibberellin noticeably decreased deleterious effect of drought stress. Result revealed that under severe drought stress, proline increased in root and shoot and gibberellin decreased. Protein (569.062mg/L), soluble carbohydrate (81.83mg/L) and insoluble carbohydrate (0.68mg/L) and Hill reaction (0.12OD/min%) significantly decreased under severe stress. Using ascorbic acid and gibberellin under drought stress had positive effect on these traits, decreased drought damages and approach the plant to control condition.

In order to investigate the effect of source and sink relationship and the planting systems in fajr rice cultivar, an experiment carried out in rice investigations institute of Amol during 2010. This experiment performed as split plot in the basis of randomized complete blocks design with 3 replications. Different planting systems in three levels (Traditional planting, Improved planting and SRI planting) were in main plots and 3 levels of sink- source relations (1/3 Panicle omitting, Flag leaf omitting and Control) were allocated in sub plots. Maximum grain yield (873.9 gram at m2) produced under system of improved planting. Improved planting grain yield had 18.3% and 25.1% significant increasing and compared to traditional and SRI respectively, because maximum and minimum number of empty spikelet in the panicle obtained for SRI and improved planting systems alternatively. Minimum number of empty spikelet in panicle gained after cutting 1.3 panicle that has 39.5 % decrease to control and shows source photosynthesis limitation in the fair cultivar.Cutting flag leaf 7.3% increased the Number of empty spikelet to control. It showed importance of flag leaf for filling spikelets. Grain yield 16/4% decreased by cutting flag leaf compare to control. Interaction effect of different planting systems and source- sink relations was significant only on the number of empty spikelet on panicle,