نشریه تولید و ژنتیک گیاهی
سال دوم شماره 1 (پیاپی 2، بهار و تابستان 1398)

Species diversity of natural enemies of Eurygaster integriceps Puton, 1881 (Hemiptera: Scutelleridae), and percent parasitism of egg parasitoids of sunn pest were studied in three regions, Saveh, Shahriyar and Qom. Upon the results of faunistic surveys, five species of Tachinidae (Diptera) including, Phasia crassipennis (Fabricius, 1794), Phasia subcoleopterata (Linnaeus, 1794), Ectophasia rubra (Girschner, 1888), Elomya lateralis (Meigen, 1824), Gymnosoma desertorum (Rohdendorf, 1947), and seven species of egg parasitoids, Trissolcusbasalis (Wollaston, 1858), Trissolcus grandis Thomson, 1861, Trissolcus pseudoturesis (Ryakhovskii, 1959), Trissolcus manteroi (Kieffer, 1909), Telenomus chloropus (Thomson, 1861),Trissolcus semistriatus (Nees, 1834) (Hymenoptera: Scelionidae), and Ooencyrtustelenomicida (Vassiliev, 1904) (Encyrtidae) were collected and identified. In Saveh, T. semistriatus and T. grandis were the dominant species which the highest percent parasitisms were 24.39% in 19th May 2015 for T. semistriatus and 21.42% in 27th May 2015 for T. grandis. In Shahriyar, T. semistriatuswas the dominant and its hieghst percent parasitism was obtained 13.41% in 18th May 2015. In Qom, T. basalis, as the dominant species, showed 19.74% percent parasitism in 22th May 2015.

A field experiment was conducted in order to evaluate drought stress on yield, radiation use efficiency (RUE) and water use efficiency (WUE) of drought resistant and susceptible cultivars of wheat at agricultural faculty research field of University of Kurdistan during 2012-2013 growing season. The experiment was split plots based on randomized complete blocks design with three replications. The main plots were different levels of irrigation (FI as irrigation based on crop water requirement, 75%FI, 50%FI and 25%FI as irrigation based on 75%, 50% and 25% of crop water requirement in FI treatment, and NI as treatment without irrigation) and subplots were three wheat cultivars (Azar2 (resistant), Gascogen and Sayonce (susceptible). Analysis of variance showed that the differences among irrigation treatments and studied cultivars were significant for economical yield (EY), biological yield (BY), and WUE in terms of economical (WUEe) and biological (WUEb) yield. The amount of EY, BY, WUEe, WUEb, and RUE were decreased with reduce in water availability rather than control treatment. The overall results showed that the amount of EY, BY, WUE and RUE of resistant cultivar were greater than susceptible cultivars. However, the harvest index of susceptible cultivars was greater than resistant one. In general, increasing WUE and RUE under drought stress treatments were two most important factors determining performance excellence of resistant cultivar rather than susceptible cultivars.

Sever coldness causes damage to the wheat and affect its growth and yield. Therefore, this experiment was conducted in controlled conditions to investigate freezing tolerance of eight wheat genotypes. Combination of temperature (+3, -3, -5, -7 and -9 °C) and genotypes (Bahar, Parsi, Pishtaz, Pishgam, Chamran, Zarin, Sivand and Marvdasht) as a factorial based on completely randomized design with three replications. Survival percentage, dry weight, number of leaves per seedling and seedling height were measured two weeks after freezing in the glasshouse. The results showed that with decreasing seedling survival due to temperature drop, dry weight, height and number of leaves in seedlings also decreased. The genotype of Marvdasht had the highest freezing resistance (-5.2 °C) was superior to other wheat genotypes in terms of dry weight, seedling height and number of leaves per seedling. Parsi and Zarin genotypes were in the next rank. While the Pishtaz genotype was a highly sensitive genotype to freezing. According to the results of this research, it can be recommended that in the regions with the probability of frostbite, it is better to avoid cultivating the Pishtaz genotype and instead use Marvdasht, Parsi and Zarin genotypes.

Phenological, molecular and metabolite analysis during vernalization in wheat show that there is a tight relationship between vernalizatio fulfillment/reproductive transition with decrease in the accumulation of some metabolites and expression of cold-induced genes/proteins. In the present review, we will describe a number of similar protective metabolites and cold related proteins which are present or expressed in both sensitive and tolerant wheat genotypes. Based on several studies duration of cold acclimation in winter genotypes is quite higher which is influenced by developmental genes and consequently the level and duration of expression of cold-lnduced proteins is longer when compared with spring genotypes. Also, the initial rate of cold acclimation in cold tolerant winter wheat is higher than the cold sensitive genotypes. Our results show that the expression patterns of cold related proteins and metabolites are consistent with the trend of the developmental factors that have regulatory effects on proteome/metabolome. In addition, sub-zero acclimation of plants in field conditions during autumn/winter seasons has significant effects on numbers, levels and patterns of cold associated proteins in compared with plants acclimated in controlled condition at low temperature but above zero temperature. This present work, provide a novel insight to uncover the molecular mechanisms behind cold adaptation in wheat and pave the way to breed wheat for cold tolerance.

A field experiment was conducted in order to evaluate drought stress effects on some physiological traits of drought resistant and susceptible cultivars of wheat at agricultural faculty research field of University of Kurdistan during 2012-2013 growing season. The experiment was split plots based on randomized complete blocks design with three replications. The main plots were different levels of irrigation (FI as irrigation based on crop water requirement, 75%FI, 50%FI and 25%FI as irrigation based on 75%, 50% and 25% of crop water requirement in FI treatment, and NI as treatment without irrigation) and subplots were three wheat cultivars (Azar2 (resistant), Gascogen and Sayonce (susceptible). Results showed that ascorbic acid (ASA) amount increased only under severe stress conditions, and other stress levels did not affect amount of this metabolite. The amount of glycine betaine (GB) and peroxidase activity were increased with increase in drought stress severity. Also, the amount of the cultivars the amount of rubisco large subunit was decreased with increasing plant age and due to drought stress in sensitive and resistant cultivars. In flowering and dough stages, irrigation cause to decrease in malondialdehyde (MDA) concentration. In general, the activity of peroxidase enzyme and the MDA concentration in drought resistant cultivar (Azar2) showed a higher increase compared to other sensitive cultivars under the stress condition. The overall results of this study showed that the resistant and susceptible cultivars have different physiological responses to drought stress. Results of this study can help breeders to select suitable cultivars for drought stress.

Wheat is the first cereal and the most important crop in the world, and due to the increasing population growth, its production is expected to increase every year. Meanwhile, Iran is considered to have a Mediterranean climate and is part of the arid and semi-arid regions of the world due to its geographical location. Under the Mediterranean climate, grain filling of wheat and other cereal usually occurs when the average temperature of the environment increases and the amount of available moisture is reduced, which would disrupt the photosynthesis and reduce the production of photoassimilates during the current photosynthesis process. However, at the same time, the demand for photosynthetic materials for grain filling and also demand for respiration of the live biomass of plant increases, and current photosynthesis does not respond to them. Therefore, the carbon needed to fill the growing grains is provided from other carbon-based sources, such as the remobilization of stored carbohydrates in the stem internodes before anthesis stage. Therefore, studying the factors affecting the transfer of photoassimilates from different parts of the plant, can provide us with a solution that can be used more effectively to reduce the damage to drought stress and the optimal yield of wheat.

Genetically improvement for salinity resistance is one of the most effective breeding methods for wheat. But understanding the mechanism, assessing and identifying salinity tolerance genes is a prerequisite for genetic modification. The role of a number of families of transcription factors has been proven in response to environmental stresses, hence, their identification and investigation facilitates the possibility of overcoming stresses. Considering the significant role of the important family of WRKY transcription factors in response to stresses, the expression of two important genes of this family including TaWRKY10 and TaWRKY53 in different tolerant and susceptible cultivars of wheat was investigated. The results showed that TaWRKY10 exhibited different expressions in susceptible wheat (Tajan) and resistant (Bam) cultivars. In resistant cultivar (Bam) under saline conditions over a period of 48 hours, TaWRKY10 showed more expression level in both leaf and root tissues than the control and also the sensitive (Tajan) cultivar. However, the expression of TaWRKY53 was different in resistant and susceptible cultivars. TaWRKY53 in susceptible cultivar (Tajan), over the period of 48 hours, showed more expression level than the control and resistant cultivar (Bam) in leaves and root tissues. Also, by using salicylic acid under salinity stress, the expressions of TaWRKY10 and TaWRKY53 in Tajan and Bam cultivars were different. In general, our results show that WRKY transcription factors can play a role in generating resistance to salinity stress in wheat and therefore can be used in genetic improvement.