Környezeti stresszek és az emelt légköri CO2-koncentráció hatása a gabonafélék antioxidáns enzimrendszerének működésére = Effect of environmental stresses and CO2 concentration on antioxidant enzyme activity.

A pályázatban a gabonafélék antioxidáns enzimeinek működését vizsgáltuk természetes és mesterséges körülmények között. Szántóföldön az időjárási tényezők közül a szárazságnak volt a legmarkánsabb hatása az antioxidáns enzimrendszerre, míg a növénybetegségek előfordulása és a fertőzések súlyossága nem mutatott szoros összefüggést az enzimek aktivitásának változásával. A szárazabb 2008-as évben a levélbetegségek kevésbé fertőztek, a kataláz (CAT), aszkorbát peroxidáz (APX ) és a glutation reduktáz aktivitása nőtt. A fitotroni kísérletek eredményei alapján megállapítottuk, hogy a fotoszintézis intenzitása szoros kapcsolatban volt a talajnedvesség szint csökkenésével, és jól jelezte az adott genotípus stressztűrő képességét. Az antioxidáns enzimaktivitás a szárazság hatására a szárbaindulás és érés idején változott meg a legnagyobb mértékben. A fejlődés korai szakaszában a magas CO2-koncentráció a stresszhatást mérsékelte, alacsonyabb antioxidáns enzim aktivitást eredményezett. Az éréskor alkalmazott emelt CO2-szint az enzimaktivitás fokozásával járult hozzá a kialakult stresszállapot negatív hatásainak mérsékléséhez. Az antioxidáns enzimrendszer magasabb aktivitása valószínűsíti az adott genotípus jobb stressztűrő képességét. A kevésbé stressztűrő fajták relatíve nagy aktivitásváltozással reagáltak a szárazságra, de antioxidáns enzimműködésük vízmegvonás hatására sem érte el a stresszmentes feltételek között nevelt, nagyon jó rezisztenciájú genotípusokét. | Within the present project, antioxidant enzyme activities were studied in cereals under natural and artificial conditions. Among weather elements, drought had the most noticeable effect on the antioxidant enzyme system, while the changes in the antioxidant enzyme activities were not closely related to the occurrence and severity of diseases. In 2008, with low soil moisture contents, leaf diseases were less virulent and activities of Catalase, Ascorbate peroxidase and Glutathione reductase increased. According to the phytotron experiments, intensity of photosynthesis was found to be closely related to decreases in the soil water level and it indicated well the stress tolerance ability of a genotype. Antioxidant enzyme activities changed most due to water stress during the stem elongation phase and grain-filling. Elevated CO2 level mitigated the effect of stress in the young developmental phase resulting in a lower antioxidant enzyme activity level. At the grain-filling stage it reduced the negative effects of stress conditions via enhancing the enzyme activities. It was also found that higher general activities of antioxidant enzymes might indicate that a genotype has better stress tolerance. Sensitive varieties had relatively higher increases in activity due to water withdrawal but even at their highest levels the antioxidant enzyme activities were lower than those under normal conditions in genotypes with good resistance

Study of yield components under heat stress conditions in wheat

High temperature tolerance can be characterised by measuring various plant productivity traits in different developmental stages. The present work investigated the effect of exposure to high temperature (30-35°C) at first node appearance, during early embryo development and in the grain-filling stage on the yield parameters of two winter wheat varieties. Periods of high temperature had diverse effects on wheat plants in different phenophases. The greatest differences between the various developmental stages were found for grain number, grain yield and thousand-kernel weight. Heat stress was demonstrated to have the least effect on total grain number and number of grains per spikelet on the main spike during the grain-filling period. The most pronounced reductions in the traits examined were detected when heat stress was applied during the early embryo development stage

Effect of elevated atmospheric CO2 level on the abiotic and biotic stress tolerance of cereals

Abstract Effect of elevated CO2 level (EC) was studied on the tolerance of cereals to elevated temperature and drought and on the resistance of wheat to fungal diseases. In general, elevated growth temperature did not affect final grain size, thus having less harmful effects than heat stress or drought during grain-filling. The plants subjected to low water supply levels or elevated temperature had higher biomass and grain yield at EC than at the ambient level. Susceptible wheat varieties were, however, usually more prone to diseases when grown at EC, while resistant varieties remained resistant even at EC

Seedling Resistance to Stagonospora nodorum Blotch in Wheat Genotypes

In two independent experiments set up in the greenhouse the seedling resistance to Stagonospora nodorum blotch was investigated in 92 varieties, breeding lines and genotypes with a known genetic background. The greatest area under the disease progress curve calculated from lesion type was 37.06, while in the case of the most resistant genotype this value was 0.38. Many of the lines and varieties bred in Martonvásár proved to have excellent resistance in terms of both percentage of infected leaf area and lesion type. Observations indicate that, depending on the aim of the experiment, the efficient selection of breeding lines is possible in the seedling stage either on the basis of the area under the disease progress curve calculated for lesion types, or on the basis of lesion types scored 7, 11 or 14 days after inoculation

Effects of the Elevated Atmospheric CO2 Concentration on the Water Use Efficiency of Winter Wheat

AbstractIn Central Europe drought is one of the most important limiting factor for autumn-sown cereals. Due to the decreasing in groundwater resources, it is a priority to make efficient use of groundwater and to promote less water-demanding forms of crop production. Water use efficiency can only be increased if cultivars with satisfactory water management traits are grown. To this end, water consumption (WU) and water use efficiency (WUE) of winter wheat genotypes were investigated in a greenhouse experiment. Plants were grown either with optimum water supply or with simulated drought in two phenophases, shooting and heading. Measurements were made on yield parameters, phenological traits and water use parameters of plants. This experiment was carried out in greenhouse chambers using the same climatic conditions, only the atmospheric CO2 concentration was regulated. 400ppm concentration was used as control and elevated levels were 700 and 1000ppm, respectively. Water use efficiency was calculated by dividing the grain yield by the water used during the vegetation. Significant differences were determined by investigating the influence of water shortage on the water use efficiency of plants during the vegetation but also meaningful alterations were found among the drought and CO2 sensitivity of varieties examined. Elevated CO2 concentration improved the water use efficiency but there were some differences among the genotypes that could be followed not only by the control but also by the drought treated plants. Simulated drought stress by the shooting decreased the WUE compared to the well watered plants but there were meaningful differences among the varieties at the different CO2 levels. The enriched CO2 resulted in a significant increase of WUE under stress condition simulated by the heading compared to the plants grown under atmospheric CO2 level. Acknowledgements: Present study was funded by the TÁMOP project 4.2.2.A-11/1/KONV/-2012-0064 project

Effect of different sowing times on the plant developmental parameters of wheat (Triticum aestivum L.)

Studies on plant development phases and yield component patterns of wheat are essential for a better understanding of adaptation in wheat. Our main aim was to carry out detailed phenological analyses of 18 wheat genotypes in three sowing times for determining the effect of sowing date on individual phenophases, and yield components. Sowing date had the single greatest effect on the start of intensive stem elongation. The longer vegetation period had a favourable effect on main spike length and on the spikelet number per spike, but had no influence on thousand-kernel weight and grain number per spike. The time between the first node appearance and start of intensive stem elongation had a significant effect on the number of reproductive tillers. A close association (R2 = 0.191) was observed during the second phase of intensive stem elongation between the boot stage-to-heading interval and the number of spikelets per spike. Two-way analysis of variance on the yield components showed that the sowing date, as a main factor, had a weaker effect on the phenophases than on morphological and developmental parameters. The insensitive allele of the Ppd-D1 gene shortened the time required for first node appearance and heading both in autumn and spring sowing

Régi magyar búzafajták kalászfuzárium ellenállóságának és minőségének vizsgálata = Studying of Fusarium blight resistance and quality of the old Hungarian wheat varieties

Magyarországon a kalászfuzárium (KF) egészen az 1970-es évek elejéig mindössze sporadikusan fordult elő. Észszerűnek tűnt megvizsgálni, hogy az 1920-1950 között nemesített búzafajták genetikailag determinált FHB rezisztenciája hozzájárult-e a gazdasági károk elkerüléséhez. Korábbi megfigyeléseink szerint a Bánkúti 1201 fajta kimagaslóan ellenállónak bizonyult a fuzáriummal mesterségesen fertőzött kísérletekben. Kísérleteinkben 1960 előtt nemesített magyar fajták KF rezisztenciáját teszteltük mesterségesen fertőzve. Ötéves adataink alapján a fajták és az e fajtákból származó törzsek átlagos KF fertőzöttsége 9,2-51,0% között alakult, 30 törzs kalászfertőzöttsége 20% alatt volt. A BKT9086-95/Mv Magvas keresztezésből származó 250 egymag-utód (SSD) módszerrel létrehozott törzs KF rezisztenciáját teszteltük kalászka fertőzéssel, üvegházban és szántóföldön. Az eredmények alapján 15 rezisztens és 15 fogékony genotípust választottunk ki bulk szegregáns analízishez. Az egyesített és a szülőkből származó DNS mintákat 81 primer kombinációval teszteltük (AFLP) és reakciónként átlagosan 5,02 polimorfizmust figyeltünk meg a szülők között. A rezisztens szülőéhez hasonló mintázat 16 törzsben volt jelen. A technológia minőség és a KF rezisztencia között laza volt, vagy hiányzott az összefüggés. A régi magyar búzafajták értékes források lehetnek a KF rezisztencianemesítésben. | In Hungary Fusarium head blight (FHB) occurred only sporadically until the early 1970s. It thus seemed worthwhile investigating whether the wheat varieties bred from the 1920s to the 50s carried genetically determined FHB resistance that contributed to the lack of economic loss. Earlier observations indicated that the variety Bánkúti 1201 had outstanding resistance to FHB in experiments artificially inoculated with Fusarium species. In our experiments inoculation tests were made on the FHB resistance of Hungarian wheat varieties bred prior to 1960. Averaged over five years, the field scab infection of these wheat varieties and of lines derived from them ranged from 9.2 to 51.0%, with infection rates below 20% for 30 lines. A total of 250 lines of single seed descent (SSD) from the cross BKT9086-95/Mv Magvas were tested for FHB resistance by means of single floret inoculation in greenhouse and field experiments. Based on the results, 15 resistant and 15 susceptible genotypes were selected for the purpose of bulk segregation analysis. DNA of the two bulk samples and the parents were tested with a total of 81 primer combinations (AFLP), and an average of 5.02 polymorphisms per reaction was found between the parents. Patterns similar to that of the resistant parent were found in 16 cases. The correlation between the technological quality data and the FHB resistance was very weak or absent. The old Hungarian wheat varieties might be valuable sources in FHB resistance breeding

Investigation of the Stress Tolerance of Winter Wheat Genotypes Under Natural Rain-Fed and Irrigated Conditions

AbstractDrought around the world is one of the most important yield reducing factor. From the cross of winter wheat varieties (Plainsman V x Mv Magma) doubled haploid (DH) population was created consisting of 174 lines to investigate the drought tolerance of the genotypes exposed to two treatments; natural rain-fed and well-watered conditions in the field.The object of the experiment was to determine the yield production capacity of the DH lines under natural rain-fed conditions and to compare the effect of changes in the yield components due to irrigation. After ripening, the wheat plants were harvested from both treatments. The plant height, the length of last internode, number of spikelets, seed number, seed weight on the main stem; the number of reproductive tillers, seed number and weight per plant was determined.The effect of irrigation was investigated on the morphological parameters and yield properties which changed due to well watered conditions in the wheat plants. Averaged over the DH lines, the heading date was significantly affected by irrigation. Irrigation significantly increased all the morphological parameters. Not only the average, but also the minimum and maximum values increased significantly for spikelet number, reproductive tiller number and plant height. Changes in the morphological parameters resulted in significant alterations in the yield components. The irrigation significantly increased the total grain number per plant, the thousand kernel weight and the grain yield averaged over the DH lines.The results showed that the morphological parameters and yield components can still be some of the most effective features to estimate the tolerance of wheat in response to stress factors. This project was supported by the János Bolyai Research Scholarship of the Hungarian Academy of Sciences and the project DROPS (EU-FP7 No. 244374)