نشریه تحقیقات علوم زراعی در مناطق خشک
پیاپی 2 (پاییز و زمستان 1396)

In order to evaluate the effect of tumble pigweed competition on yield, yield components and seed quality of six cultivars of sunflower; an experiment was conducted with factorial layout based on a completely randomized block design at the research farm of College of Agriculture, University of Birjand in 2012. The factors were four weed densities (0, 5, 10 and 15 plants/m2) and six cultivars of sunflower (Azargol, Jame Isfahan, Syrna, Farrukh, Progress and Euroflour). The results showed that by increasing weed density, yield and yield components of sunflower were decreased. By increasing weed density from zero to 15 p.m2, grain yield of sunflower was decreased up to 40.2%. Jame Isfahan cultivar produced the highest seed yield (5.789 kg/ha), and Farrukh cultivar had the least percentage of seed yield loss in weed density of 15 p/m2. Generally, Progress, Euroflour and Jame Isfahan cultivars had the most competitiveness and Azargol cultivar showed the least competitiveness against tumble pigweed.

In order to study the effect of drought stress on parent plant of soybean commercial cultivars on seed germination and seedling field emergence, field and laboratory experiments were conducted during 2014-2015. Seeds of six soybean commercial cultivars including Williams, M-11, M-9, Saba (L-17), Clarke, and Zane were produced at three drought stress levels on parent plant including irrigation after 50 (optimum irrigation), 100 (medium stress), and 150(sever stress) mm evaporation from Class A pan. After harvest, normal seedlings percent were determined by standard germination, cold and accelerated ageing tests in laboratory. Also, field emergence index was calculated. Results revealed that by increasing drought stress on parent plant intensity, normal seedlings’ percentage and field emergence index of studied cultivars at laboratory and field increased. The most normal seedlings’ percentage was related to the produced seeds of Zane and Saba (L-17) cultivars under 100 mm and Clark cultivar seeds produced at 150 mm drought stress of evaporation from Class A pan. Also, Zane cultivar seeds produced at 150 mm drought stress of evaporation from Class A pan had the most field emergence index. Normal seedlings’ percentage after accelerated ageing test had the most correlation with seedling field emergence and therefore this test could provide us with a more precious estimation of seedling field emergence.

In order to evaluate the effect of terminal drought stress on yield and yield components and harvest index of bean cultivars, a factorial experiment based on completely randomized  design with 3 replications was conducted in green house at faculty of agriculture, Gonbad Kavoos University. The treatments included terminal drought stress (Podding stage) in 3 levels i.e. full irrigation as the control, slight water stress (30% water depletion of filed capacity) and intensive water stress (70% water depletion of field capacity); and the second factors were four bean cultivars including withe (Daran), red (Azadshahr), green (Sanrey) and pinto (Saman). The seeds were planted in 12 kg pots containing soil. In this study; traits such as number of pods per plant, number of seeds per pod, seed weight, seed weight per plant, total dry weight and harvest index were measured. Results showed that terminal drought stress had a significant effect on all of the studied traits. Effects of cultivar on all traits, except harvest index and number of seeds per plant, were similar to results of drought stress. It was also observed that interaction effect of drought stress and cultivar on all studied traits except the number of pods per plant, was significant. The lowest and the highest seed yields were obtained for withe and pinto beans during intensity with 0.96 and 1.25 gr/plant, respectively. Overall, results of this study revealed that pinto and withe beans had the lowest and the highest sensitivity to the terminal drought stress, respectively.

Due to increased environmental issues, more attention has been paid to biofertilizers. This experiment was conducted as factorial with completely randomized design with three replications. Treatments included irrigation at 100 (control), 75 and 50% FC and humic acid spraying at 0, 200 and 400 mg l-1. The most and the least plant height, fresh and dry weight, number of lateral branches, stem diameter and root dry weight were observed for irrigation at 100% FC and 50% FC, respectively. Whilst, the highest essential oil percentage and essential oil yield was achieved for irrigation at 50% FC and 75% FC, respectively. Interaction of 400 mgl-1 humic acid and irrigation at 100% FC had the most plant height, fresh and dry weight, stem diameter, and root dry weight. Meanwhile, application of 400 mg humic acid and irrigation at 50% FC and 75% FC had the highest essential oil percentage and essential oil yield, respectively. The interaction was not significant for number of lateral branches. Vegetative growth decreased with increasing drought stress and increased with increasing humic acid application. These results suggested that humic acid alleviated drought stress on lemon balm.

In order to explore the effect of chemical and Nano bio-fertilizer on quality and quantity of sesame genotypes, an experiment was conducted in a completely randomized block design with three replications at Agricultural Research Institute of Zabol University in 2014-2015 growing season. Treatments included three sesame genotypes (Ardakan, Isfahan and Sistan landrace) as main plot and fertilizer type included 100% of recommended chemical fertilizer, 75% of recommended chemical fertilizer + 1.5 kg.ha-1 of nano bio-fertilizer, 50% of recommended chemical fertilizer + 1.5 kg.ha-1 of nano bio-fertilizer, 25% of recommended chemical fertilizer+ 1.5 kg.ha-1 of nano bio-fertilizer and 1.5 kg.ha-1 of nano bio-fertilizer as subplots. The results showed that using 100% of recommended chemical fertilizer caused significant increase in plant height, number of capsule per square meter, thousand seed weight, seed yield, and biomass. The highest of capsule number per square meter (2256 number) was obtained from Sistan landrace with the application of 100% of recommended chemical fertilizer. The number of capsule per square meter, number of seeds per capsule, thousand seed weight, seed yield, biomass, harvest index, chlorophyll index and protein percentage showed significant increase in Sistan landrace in comparison with the other genotypes. The results showed that the highest seed yield was obtained (1428.07 kg.h-1) from Sistan landrace and the highest oil percentage (41.7%) was obtained from Isfahan genotype. According to the results, it could be said that the 100 kg.ha-1 of potassium sulfate, ammonium phosphate and urea application can be beneficial in increasing yield and improving growth characteristics of sesame.

Secondary metabolites are a diverse group of molecules that help to compatibility of plants especially in face of stress. Flavonoids and anthocyanins are parts of these compounds. In this study, effect of manganese (concentration of 80 ppm) on enzymatic and non-enzymatic activity rates of cum, 18-21 days after germination, was measured at 4 different times of 0 (control), 24, 48, 72 and 92 hours after stress applying. All of the experiments were performed with 3 independent replications and completely randomized design. Analysis of variance and comparison of means were done using SAS after measurement of different concentrations. Due to manganese stress, content of total flavonoid and anthocyanin and activity of some antioxidant enzymes increased significantly compared to control, as the most enzymatic and non-enzymatic activity rates were observed 48 hours after stress applying. Guaiacol peroxides enzyme showed the most and the least activity rates 24 hours (88.24% higher than control) and 96 hours after stress, respectively. Total results showed that increased flavonoid and anthocyanin after stress applying were consequences of oxidative stress originating from manganese absorption and activation of plant antioxidant system.

Application of bio-fertilizers as plant nutrition is one of the vital solutions to increase plant yield and its quality. Therefore, pot experiment with factorial of completely randomized design with three replications was conducted in the research greenhouse of Zabol University. The first factor was bio-fertilizers which contains two levels of non-inoculated and non-sterile (control) and inoculated soil growing media with bio-fertilizers: Nitrogen fertilizer 1 (microorganism Azeotobacter) and phosphate fertilizer 2 (containing microorganisms Pseudomonas putida, Pantoea agglomrans)  and the second factor  was alfalfa extract from freshly harvested alfalfa and last year harvested alfalfa (old) which was used as foliar and soil application with two levels of concentrations  2 and 4 per thousand with control(total 9 levels). In this experiment, the sunflower (Helianthus annuus L.) was cultivated in non-sterile soil growing media. Pots field capacity was kept at 70% by weighting. The results showed that the highest concentrations of Fe (132.35 mg.kg-1), Mn (89 mg.kg-1), chlorophyll a (2.29 mg.g-1), chlorophyll b (1.07 mg.g-1) and carotenoids (1.29 mg.g-1) in sunflower shoot belonged to inoculated growing media with bio-fertilizers and the foliar consumption fresh extracts of alfalfa. The highest potassium concentration was seen in shoot (0.97 percent) in non-inoculated growing media and the foliar consumption fresh extracts of alfalfa was observed at four per thousand level. Resulted also indicated that the maximum dry weight (28.93 g.pot-1) belonged to non-inoculated with bio fertilizers and fresh foliar application at four per thousand level.

In order to evaluate the allelic diversity of Glutenin Subunits in estimating the quality of bread wheat, 29 promising dryland wheat genotypes were studied by SDS-PAGE. It was found that for Glu-A1 locus, 1 allele was observed for Karim, Rasad, Sabalan, Ohadi, 3, 4, 5, 8, 9, 10, 11, 14, 17, 19, 21, 22, 23 and 24  genotypes, for 6, 7, 12, 13, 16, 20, Homa and Rijaw genotypes, allele 2* and for 16, 18 and Azar2 genotypes, null allele was observed. In GLU-B1 locus, 7+9 allele was seen for Ohadi, Rijaw, 5, 9, 13, 16 and 21 genotypes, 7+8 allele was observed for Azar2, Homa, Karim, Rasad, 7, 8, 10,12, 19, 20, 21 genotypes, 17+18 allele was seen for Sabalan, 3, 4, 6, 11, 18, and 24 genotypes, and 13+16 allele was observed for 14, 15, 17 and 23 genotypes. In GLU-D1 locus, 5+10 allele was observed for Ohadi, Rijaw, Karim, 5, 9, 11, 13, 14, 15, 22 and 23 genotypes,  2+12 allele was observed for Azar2, Sabalan, Rasad, 3, 4, 6, 7, 8, 10, 12, 16, 17, 18, 19, 20, 21 and 24 genotypes. Significant Positive correlation was found between grains protein with zeleny number and significant negative correlation was observed between protein and starch percentage.  Based on principal component analysis, two factors were identified that can explain 72/8 percent of diversity.  Based on stepwise regression analysis, significant correlations were also found between null allel and hardness, and between 7+9 allel and zeleny.

Seed size and seed position on native rootstock affect seed quality. To study the effect of seed position on native rootstock on yield and yield components of guar under drought stress, an experimental split plot in a completely randomized block design with three replications was conducted in June 2016 at the research station in the Mollasani City in Khuzestan. The treatment consisted of drought stress (main factor) in three levels: control (90% FC), moderate stress (60% FC) and high stress (30% FC) and seed position (sub) on 9 levels including seeds elementary, middle and bottom covers of the bottom, middle and top of the plant. Analysis of variance showed that drought stress affected all traits and seed position affected all traits except number of seed per pod, significantly at 1% level. The interaction effect of seed position and drought was significant on the number of branches, number of pods per plant, seed weight and seed yield at 1% and plant height, biological yield, harvest index, and germination percentage at 5% level. Comparison of mean showed that the seeds of the lower and middle pods had better germination percentage than the plant pods. Also, under drought stress conditions, lower and middle pod seedlings showed better yield.

To investigate simultaneous effects of Thiobacillus bacteria, sulfur, and organic fertilizer treatments on chemical forms and quantity of phosphorus absorption by corn, an experiment was conducted based on completely randomized design using eight treatments and three replications in a greenhouse located in Hashtgerd, in 2014. Treatments included control, Thiobacillus, sulfur, organic fertilizer, and two ways and three ways combinations of these factors. Results showed  that the highest and lowest yield, root dry weight, root fresh weight, shoot weight, and phosphorus uptake were obtained in the Thiobacillus + sulfur +organic fertilizer treatment and control treatment (without any added Thiobacillus, sufur, and organic fertilizer), respectively. Thiobacillus + sulfur +organic fertilizer treatment caused significant change in inorganic and organic phosphorus elements and enhanced available phosphorus in soil, so that the highest available phosphorus was related to the treatment number eight with 16.22 mg/kg soil and this treatment showed four more mg of available phosphorus compared with control treatment. On the other hand, the Thiobacillus +sulfur treatment resulted in more reduction in mineral forms of phosphorus including dicalcium phosphate and apatite joint phosphorus compared with other treatments. The most organic and total phosphorus in soil was observed in sulfur + organic phosphorus and Thiobacillus + organic phosphorus treatment, respectively. Taken together, results of this study showed that using Thiobacillus bacteria along with sulfur and organic fertilizer would result in enhanced phosphorus uptake and improved phosphorus status in the plant, which would cause more reduction in chemical fertilizers in extensive scale.