جستجوی مقالات مرتبط با کلیدواژه "سورگوم" در نشریات گروه "منابع طبیعی"

Climate change drastically reduces the amount of water available to plants and increases the severity and frequency of droughts. By the end of this century, it is anticipated that droughts will continue to increase significantly. Drought stress, as one of the major climate events, induces physiological and morphological alterations, which can restrict crop growth, yield, and quality. In recent years, separate research projects and studies in the country have evaluated the effects of drought stress on grain maize, forage maize, grain sorghum, forage sorghum, grain millet, alfalfa, and clover yields, as well as the effects of drought stress on their yield gap. However, if the results of these separate studies were evaluated together, it would have been possible to compare the drought sensitivity and tolerance of various crops. Consequently, the optimal crop to plant under drought-stress conditions in the nation's agroecosystems would be determined. The meta-analysis is a statistical analysis that can assess the aggregate effects of numerous studies conducted under varying conditions. In other words, meta-analysis is a statistical technique for integrating the findings of multiple studies in order to comprehend a problem. The purpose of this meta-analysis was to determine the impact of different drought stress levels on the yields of grain maize, forage maize, grain sorghum, forage sorghum, grain millet, alfalfa, and clover.

In this study, the data obtained from 145 final reports of the Agricultural Research, Education, and Extension Organization (AREEO) and published articles over the past decade were analyzed using the meta-analysis method. This included grain sorghum (18 studies), forage sorghum (21 studies), grain maize (28 studies), forage maize (23 studies), grain millet (18 studies), alfalfa (17 studies), and clover (20 studies). In addition to the difference in quantitative results between studies, the effect size variance was utilized in this method. Consequently, the means, standard deviations, and sample sizes (replications in each study) for the control and evaluated treatments were determined. After classifying the data, the reaction ratio (R) and its natural logarithm were calculated. Subsequently, the method determined which treatments have additive or decreasing effects on yield under drought stress conditions, as well as which treatments had no positive or negative impact on yield. Utilizing the T-test, a group comparison was conducted between the mean yield under drought stress conditions and the mean yield under normal irrigation conditions in order to determine the significance level of yield changes caused by drought stress. The statistical analysis and preparation of the figures were performed by Excel.

According to the findings of the meta-analysis, the overall effect of drought stress on the yield of all seven crops was significant for grain sorghum (-16.30%) (P<0.05), forage sorghum (-18.27%) (P<0.05), grain maize (-31.75%) (P<0.01), forage maize (-33.24%) (P<0.01), grain millet (-25.66%) (P<0.01), alfalfa (-30.79%) (P<0.01), and clover (-32.14%) (P<0.01). The yield reductions in grain maize, forage maize, alfalfa, and clover were significant under all levels of drought stress, whereas grain sorghum, forage sorghum, and grain millet yield reductions were significant only under severe drought stress. The yields of grain sorghum, forage sorghum, grain maize, forage maize, grain millet, alfalfa, and clover decreased by 10.03, 11.84, 18.21, 20.27, 14.13, 19.74, and 20.37%, respectively, under moderate drought stress, and 21.98, 25.41, 39.09, 41.37, 32.55, 40.13, and 42.08%, respectively, under severe drought stress.

As a result, it is impossible to cultivate and develop grain maize, forage maize, alfalfa, and clover in areas with limited water resources without significantly reducing yield. According to the findings of this meta-analysis, grain sorghum, forage sorghum, and grain millet with a moderate drought stress tolerance threshold could be recommended for cultivation in regions where drought stress conditions are likely to occur.

In order to evaluate the effect of water stress on grain yield and its components and parameters of dry matter remobilization in sorghum genotypes (Sorghum bicolor L.), a field experiment as a split plot design was carried out with three replications in 2014 at the research farm of the southern Khorasan Agriculture and natural resources research and education center. Main factors including normal irrigation (control), irrigation cut off in vegetative growth stage (emergence of terminal leaf as rolled) and irrigation cut off in generative growth stage (50% of plants in start of flowering) and genotypes including KGS29, MGS2, Sepideh, KGFS27, MGS5, KGFS5, KGFS17, KGFS13 and KGFS30 were as sub factors. Results showed that water stress had significantly effect on grain yield, biological yield, harvest index, 1000 seed weight, seed number per panicle and caused to decrement of them. The grain yield reduction was about 42% at the highest level of water stress (irrigation cut off in vegetative growth stage) in comparison with the control. The genotype KGFS13 had the highest grain yield, biological yield and harvest index. The effect of water stress was significant on ARDM (Amount of Remobilized Dry Matter) and %REP (Remobilization Percentage) at %5 probability level and this effect was not significant on %REE but each of those parameters were highly increased with water stress inducing and stress severity increasing. Generally, remobilization process can be considered as one of the optimal and selective mechanisms in sorghum cultivars and genotypes, especially in terms of drought stress condition.

Mycoflora of hybrid sorghum seeds in line production areas of Khorasan Razavi Seed health analysis was carried out on 30 Sorghum bicolor cv. speed feed(line AS9) seed samples belonging to two growing seasons (2001-2004) which were routinely submitted by Feizabad Research Center, Khorasan Razavi provience to Seed and Plant Certification and Registration Institute, Iran. Applying simple blotter-, deep freezing blotter-, and agar plate- methods for detection of seedborne mycoflora revealed the presence of Fusarium verticilloides, Bipolaris sorghicola, Cladosporium sp., Alternaria sp., Penicillium spp.,and Cephalosporium acremonium in seed samples at the rates of 0.5, 4.5, 16, 19.25, 21 and 0.75 percent, respectively. Using washing test, teliospores of Sphacelotheca cruenta and Sporisorium sorghi at the rates of 12 and 42 teliospores/Kg seed were detectedon the basis of teliospore morphology.