جستجوی مقالات مرتبط با کلیدواژه « bread wheat » در نشریات گروه « اکولوژی »

The effect of potassium sulfate on drought tolerance of wheat was studied in which the first factor was five wheat cultivars (Kavir, Sistan, Roshan, Bam and Boulani) and the second factor was two K levels (0 and 100 kg.ha-1 potassium sulfate). Two separate experiments were carried out in drought stress and normal conditions and the data were combined for statistical analysis. The drought stress was imposed on the basis of 110 mm evaporation from Class A evaporation pan and the normal conditions were provided on the basis of conventional crop water requirement in the region. Drought stress resulted in the loss of all traits, particularly grain yield by 39.37%. Among grain yield components, grain number per spike and 1000-grain weight were more sensitive to drought stress than fertile tiller number. The significant, positive correlation between grain yield and grain number per spike (r = 0.77) under drought stress implied its importance for grain yield under stress. Cultivars showed different responses to moisture status. Although drought stress resulted in the loss of grain yield, cv. Bam was more drought tolerant than the other cultivars and produced fairly high yield. The application of 100 kg.ha-1 potassium sulfate increased grain yield by 8% under normal conditions and by 10% under drought stress compared to non-fertilized (control) treatment. The effect of K on increasing peduncle length, grain number per spike, grain number per plant, biological yield and grain yield was more under stress than under normal conditions. Under stress conditions, K application can mitigate drought-caused losses by keeping photosynthesis activity and/or preventing the loss of photosynthesis and assimilation. So, it improves drought tolerance under stress conditions.

The current study was carried out to study the traits affecting grain weight and the effects of some physiological parameters on grain yield of autumn wheat genotypes under optimum and drought stress conditions. So, 16 bread wheat genotypes were evaluated under optimum moisture conditions during growth season and under post-anthesis drought stress until physiological maturity based on a randomized complete block design with two replications. The measured traits included grain yield, grain weight, retranslocation of reserves from stem to grain, the efficiency of stem in translocating its reserves, the partial share of stem reserves in yield, biological yield, harvest index and stress tolerance index (STI). The results showed that grain yield had a high, positive correlation with biological yield under both optimum and stress conditions. The highest correlation coefficients were observed between grain weight with biological yield, the number of grains per spike and harvest index. Under stress conditions, only harvest index and yield had significant correlations with stress tolerance index of genotypes. Stepwise regression analysis under optimum and stress conditions showed that biological yield and harvest index were the most important components which explained the variations of grain weight.

The novel salt-tolerant cereal, Tritipyrum, is the third artificially-synthesized crop plant. The agronomic traits and grain yields of 13 primary 6x Tritipyrum lines were evaluated and compared with five modern 6x Triticale lines and nine bread wheat cultivars at Shahid Bahonar University, Kerman, Iran in a randomized complete block design. The Tritipyrum lines had higher grain yields (2.25 gr/plant) than the Triticale lines (1.97 gr/plant) and wheat cultivars (0.84 gr/plant). Although the Tritipyrum lines were late-maturity, they were shorter than the Triticale lines and wheat cultivars and superior in many characters such as penultimate leaf area, flag leaf length, penultimate leaf length and time to milky ripeness. Genotypes were divided into four groups for agronomic and morphological traits and four groups for grain yield by cluster analysis. All clusters showed significant differences for all traits and the first cluster, which comprised of Tritipyrum lines, had a higher mean grain yield than the other clusters. The results of this first large-scale trial indicated the high adaptation of Tritipyrum lines to climatic conditions of Kerman province in south-east Iran.