جستجوی مقالات مرتبط با کلیدواژه "susceptible" در نشریات گروه "زراعت"

In order to determine the susceptible and tolerant lines of sunflower to drought stress, a completely randomized block design with three replications was conducted at Karaj seed Oil Research Institute. In this study, 12 different sunflower lines have been identified for the characteristics related to drought tolerance and were selected two susceptible and tolerant lines. Initially, sunflower lines were cultivated in two separate experiments under normal irrigation and drought stress conditions. Drought stress was carried out through stop irrigation in step 2 to 8 leaves formation. The studied traits included agronomic characteristics and drought stress indices of sunflower, such as Plant height, Stem diameter, Head diameter, Seed yield, Leaf Area Index, Relative Water Content, SSI and STI. The studied traits were significantly different in water stress, except stem diameter. After analyzing the tested factors and analyzing the data, the results were obtained by analyzing the percentage of variation of studied traits, calculating stress indices (drought tolerance indices, drought sensitivity) and dendrogram drawing from Cluster analysis of cultivars was identified. According to the results, in terms of water deficit stress, RGK26 and RGK41 produced the highest and the lowest seed yield per plant. Comparison of traits can identify BGK221 as susceptible line and RGK46 as tolerant line among 12 studied lines. Also, correlation between traits showed that drought tolerance index (STI) was positively correlated with almost all traits. In addition, grain yield was positively correlated with all traits except plant height.

Bacterial leaf streak of wheat caused by Xanthomonas translucens pv. undulosa is one of the most important diseases of wheat which has threatened wheat production in some regions in Iran in recent years. Considering the importance of the disease in the country and lack of information about reaction of wheat cultivars and candidate lines of Iran to the disease, the reaction of 113 wheat commercial cultivars and candidate lines from the national irrigated wheat breeding programs of Iran were evaluated under high natural disease pressure at agricultural research station of Boroujerd, Lorestan, Iran, in 2017-18 cropping cycle. The results showed that all wheat commercial cultivars and candidate lines were susceptible to the disease with scores varied from 71 to 99 based on a 00-99 scale. Ten commercial cultivars including Parsi, Setareh, Meraj, Kalateh, Tirgan, Ehsan, Gonbad, Morvarid, Darya, and Narin, and six candidate lines including M-93-11, S-94-7, S-94-12, S-94-22, N-94-8, and MS-93-3 were rated highly susceptible with scores from 94 to 99. The present study, which is the latest and most recent evaluation on the reaction of wheat to bacterial leaf streak in Iran, may open a window for further research and development of resistan wheat cultivars to the disease.

In order to study some morphological and physiological traits of susceptible (Hayola308) and tolerant (SLM046) genotypes of canola to drought stress, an experiment was conducted in CRD design with factorial split in time arrangement. The applied factors were genotype (susceptible and tolerant) and irrigation condition (non-stress and stress). The stress was applied at before flowering time and the traits were measured at 24, 48, 72 and 96 hours after it in both condition. The result showed a reduction in dry weight of root in Hayola308 genotype, and a significant increase in root to shoot length ratio, fresh weight of root and malondialdehyde level (MDA) in SLM046 genotype. The 48 hours after drought stress, the fresh weight of shoot in SLM046 genotype was higher than Hayola308 genotype. Relative water content (RWC) in SLM046 and Hayola308 at 24 hours after stress were 88.59% and 38.52%, respectively. In Hayola308 genotype, hydrogen peroxide (H2O2) content in stress condition was higher than non-stress ones. There was not a significant difference among studied treatments for electrolyte leakage. In general, the increase of root length, root to shoot length ratio, RWC, fresh weight of root and the difference between fresh and dry weight of root and shoot and no change in dry weight of root and H2O2 content in SLM046 genotype indicated that this genotype had traits which could assign tolerance to drought stress.

In order to compare the reaction of 13 millet accessions from gen bank collection to late season drought stress and with the aim of completion of gen bank information، specific assessments and determination of the best indices for drought tolerance، two separate experiments based on randomized complete block design with three replications were conducted at the Agricultural Research Center of Southern Khorasan during 2005 and 2006. The first experiment was conducted under normal irrigation and the second experiment was taken place under drought stress conditions (irrigation up to the 10% of panicle emergence). Experiment treatments included 13 millet accessions. Results showed that accessions number 15-143 (Southern Khorasan) and 15-24 (Yazd) had the highest two years average for grain and dry forage yields and number 15-132 (Hamadan) had the lowest grain yield among all accessions. Evaluation of accessions in terms of drought tolerance was made using MP، TOL، SSI، GMP، STI and HARM indices. HARM، GMP and STI were recognized as the best indices for severance of drought tolerant accessions according to the high correlation of these indices with grain and dry forage yields under stressed and non-stressed conditions. Based on using three dimensional graphics and accessions positioning on it، numbers 15-143 (Southern Khorasan)، 15-131 (Southern Khorasan) and 15-24 (Yazd) were identified as the most yielding and tolerant accessions to drought stress.

Reactions of 74 promissing genotypes from temperate, cold, northorn warm and humid and Southern warm and dry agro-ecological senes together with a commercial check and a susceptible check were evaluated for their reactions to common bunt in Karaj and Kermanshah, during 2002-2004 growing seasons. Genotypes were evaluated under artificial inoculation using a randomized compelet block desigen with three replications. Mean percentage of infected spikes were analysed and genotypes were classified. Combined analysis of variance on mean percentage of infected spikes showed significant differences between genotypes in different agro ecological zones. Among temperate agro-ecological zone entries, commercial cultivar‘Pishtaz’ and two sister lines of ‘Alvand/MV17’ with 0.3,0.9 and1.1percent infection, respectively, were resistant and Flt/Tajan’with 63.8% was the most susceptible genotypes, Bolani had 48.8% infected spikes. Among cold agro-ecological zone entries‘K2340/Sx//Mt/Gb/3/K340 /Fr/Pi/"S"/Kt54*//Nar"S"/5/1-32-1317//II/Y50E/3/Cno/Jar//On/4/Anza/3/Pi/ Nar/Hys with 0.5% infection was resistant.Commercial cultivar ‘Shahreiar’ with 33.7% infected spikes was susceptible and susceptible check had 63.7% infected spikes. Among nothern warm and humid Agro-ecological zone entries Chum/8/3Hel/3*Cno7g/2*Seri/4/Star with 10.1% infection was moderately susceptible and commercial check ’Tajan’ with 15.8% and susceptible check with 50.3% infected spikes were susceptible. Among Southern warm and dry agroecological zone entries Janz/Attila/4/San/Ald"S"//Avd/3/Kea"S"/Ghk"S" with 4.2% infected spikes was resistant. Commercial cultivar ‘Chamran’ and susceptible check with 17% and 58% infected spikes respectively, were susceptible. Considering that in commercial irrigated wheat cultivars resistant cultivars to common bunt are highly reguested in Iran, the resistant genotypes found in this study are very useful to be grown as cultivars or used as sources of resistance in wheat breeding programs.

The susceptibility of 52 wheat and 12 barley cultivars to two pathovares of cereal’s bacterial leaf streak (BLS) was studied. The experiment was carried out under field conditions. Seeds of all cultivars were grown using randomized block design with 4 replications in the Alborz Research Institute, Karaj in 1999-2000 cropping season. In spring of 2000, 20 days after inoculation of seedlings with a suspension of bacteria (adjusted approximately to 109 cfu/ml) the percentage of infected area on the lower leaves were scored from %1 to %75 in 5 levels. Results showed that among wheat cultivars, Kavkaz, P.K., Sardari, Adle and Golestan were more susceptible and Kaveh, Mahooti, Maroon, Shiroudi, Chenab, Niknejad, Bayat, Moghan 1, Morocco, Cross Azadi, Alborz, Hirmand and Arvand cultivars showed resistant reactions to BLS. In barley cultivars Zarjo, Karoon, Dasht, Goharjo, were more susceptible and. Aras, Eram and Valfajr were more resistant.