Small-scale vegetation patterns are frequently the results of plant-plant interactions such as facilitation and competition. Facilitation should be particularly pronounced when both abiotic and biotic stresses are high, but few studies were conducted in such habitats. In heavily-grazed pastures on the eastern Tibetan Plateau, an area with both high abiotic stress and strong biotic disturbance, we made relevés of herb species both beneath and outside canopies of three shrub species (Spiraea alpina, Sibiraea angustata and Potentilla fruticosa) differing in palatability and canopy structure. Herb species richness (S), pooled cover (PC) of all species, number of flowering species (FS) and number of inflorescences of all species (IN) were greater outside than beneath the shrub canopies. Evenness (J), in contrast, was smaller outside, while Shannon’s diversity index (H) was the same. Differences in S and J between plots beneath and outside the shrub canopies were greater in the case of P. fruticosa than in the cases of S. angustata and S. alpina, but differences in PC, FS or IN did not depend on the shrub species. Among the common species (frequency ≥6), 47–85% were equally frequent beneath and outside the shrubs, 13–39% were more frequent outside and 3–13% were more frequent beneath the shrubs. For the rarest species (frequency < 6), however, more species occurred beneath than outside the shrubs. The ordination diagram showed a clear separation between the relevés outside and beneath the shrubs and a gradient from P. fruticosa via S. alpina to S. angustata, accompanied by a distinct decrease in the extent of the difference between the vegetation beneath and outside the shrub canopies. In conclusion, the three shrub species facilitated some species in the herb layer and each shrub species had a specific impact, related to its canopy structure and palatability but also to the grazing pressure, which was greater around the P. fruticosa shrubs than around S. alpina and S. angustata.
Authors:E. Farshadfar, R. Mohammadi, M. Aghaee, and J. Sutka
Water deficiency is a major constraint in wheat production and the most important contributor to yield reduction in the semiarid regions of the world. species related to wheat are valuable genetic sources for different traits including resistance/tolerance to biotic and abiotic stresses. To locate the genes controlling the physiological and agronomic criteria of drought tolerance, disomic addition lines of secale cereale cv. Imperial (donor) into the genetic background of Triticum aestivum cv. Chinese Spring (recipient) were tested under field, greenhouse and laboratory conditions. Disomic addition lines exhibited significant differences for relative water content (RWC), relative water loss (RWL), water use efficiency (WUE) and stomatal resistance (SR), indicating the presence of genetic variation and the possibility of selection for improving drought tolerance. Three physiological variables, RWL, WUE and SR, with high correlation with the stress tolerance index (STI) and germination stress index (GSI), contributed 69.7% to the variability of yield under stress (Ys) in the regression equation. Based on the physiological multiple selection index (MSI) most of the QTLs controlling physiological indices of drought tolerance were located on chromosomes 3R, 5R and 7R. The contribution of addition line 7R to the MSI was 47%. The evaluation of disomic addition lines for STI and GSI revealed that most of the QTLs involved in these quantitative criteria of drought tolerance are located on 3R and 7R. Cluster analysis and three dimensional plots of Ys, yield potential (Yp) and MSI indicated that 3R and 7R are the most important chromosomes carrying useful genes for improving drought tolerance.
Authors:A. Morgounov, A. Abugalieva, and S. Martynov
Winter wheat yield in three administrative regions of Kazakhstan (Almaty, South Kazakhstan, and Zhambyl) was analyzed during 1972-2009. Yield gains were greatest during 2000–2009, but absolute yields remain low (1.5–1.7 t/ha) and much below the production potential. Changes in important weather parameters over the same time period were also analyzed. Results indicated significant (15–20%) warming in winter and spring, as well as some increase in precipitation (spring and annual), especially in the last ten years. Increased temperatures in winter and precipitation in spring/annually were positively correlated with winter wheat yield, while increased temperatures in May had a small but negative effect on grain yield. Data from the four stations of the official variety testing system from 1972–2009 were also analyzed to evaluate the effect of variety on yield and quality. Genetic gain of the varieties released in the 1990s and 2000s, compared to Bezostaya 1 (1960s), was around 30%. However, the bread-making quality of new varieties, as well as the overall grain quality in variety trials, were reduced in protein content, with deteriorated dough physical properties, and therefore did not meet superior class requirements. Genetic diversity (coefficient of parentage and Shannon’s diversity index) of the winter wheat varieties tested in the 2000s was broader compared to the 1970s and 1980s, reflecting enhanced international cooperation and germplasm exchange. A negative association between genetic diversity parameters and some quality traits can be attributed to the utilization of more diverse high yielding parents with limited grain quality potential. Further yield increases and reductions in the yield gap should be based on improved agronomy, and the use of broadly-adapted varieties, with resistance to the biotic and abiotic stresses likely due to climate change.
Authors:J. Pintér, E. Kósa, G. Hadi, Z. Hegyi, T. Spitkó, Z. Tóth, Z. Szigeti, E. Páldi, and L. Marton
The level of UV-B radiation reaching the surface of the earth is increasing due to the thinning of the ozone layer in the stratosphere over recent decades. This has numerous negative effects on living organisms.Some of the Hungarian inbred maize lines examined under the climatic conditions in Chile exhibited an unusually high proportion of pollen mortality, flowering asynchrony and barrenness. The evidence suggests that this can be attributed to the approx. 30% greater UV-B radiation in Chile.The investigation of this problem within the framework of abiotic stress breeding programmes is extremely important in the light of the global rise in UV-B radiation, which may make it necessary to elaborate a selection programme to develop inbred lines with better tolerance of this type of radiation.In the course of the experiment the same ten inbred lines, having different maturity dates and genetic backgrounds, were tested for five years in Chile and Hungary. The tests focussed on anthocyanin, a flavonoid derivative involved in the absorption of damaging UV-B radiation.Averaged over years and varieties, the total anthocyanin content in the leaf samples was significantly higher in Chile than in Hungary. This was presumably a response at the metabolic level to the negative stress represented by higher UV-B radiation.In the five early-maturing flint lines the anthocyanin contents were more than 45% greater than those recorded in Hungary. This suggests that these genotypes, originating from northern regions, were not sufficiently adapted to the higher radiation level. In these samples higher UV-B caused a sharp rise in the quantity of anthocyanin, which absorbs the dangerous radiation. In late-maturing genotypes the initial content of the protective compound anthocyanin was higher at both locations, so in these types the high radiation level was not a problem and did not cause any substantial change.Similar conclusions were drawn from the results of fluorescence imaging. The F440/F690 ratio indicative of the stress level was higher in late lines with a high anthocyanin content, good tolerance and good adaptability.
Some idea of what paprika first looked like can be obtained from a relief found on the Tello Obelisk, thought to have been carved around 800-1000 AD. The introduction of paprika into Europe can be dated from the first voyage of Christopher Columbus to America in 1492. Portuguese ships carried paprika from Spain to Arabia, and from there it spread to all the areas conquered by the Ottoman Turks, including Hungary (Andrews, 1984). The first large-fruited (Kalinkói, Várnai), tomato-shaped and horn-shaped types were introduced into Hungary by Bulgarian market-gardeners in the late 19th century. These market-gardeners maintained their paprika varieties through the positive selection of individual plants. The first organised breeding of vegetable peppers is linked with the name of Lambert Angeli (1916-1971), while the most successful paprika breeder in Hungary was István Túri (1933-1999). No ready-made paprika lines are available on the market, so paprika breeders use a greater proportion of lines of their own breeding than those working with other species. It is an advantage, however, that in paprika many quality traits can be selected on the basis of phenotypical traits, so in many cases visual evaluation can be employed in place of the far more costly measurement of performance traits. A further advantage is that the paprika species behaves decisively as a self-fertilised crop, the plants require little space, and the species is cosmopolitan. To improve selection efficiency, an environment is required that accentuates differences for the traits to be selected. In Hungary this can best be achieved in a field environment, which is also less costly. The following traits can be tested in field nurseries: tolerance (CMV, Xanthomonas, etc.), horizontal resistance traits (purple nodes, leathery leaves, etc.), development rate, abiotic stress tolerance, susceptibility to sunburn and purple fruit, undesirable fruit shape and surface, lack of pungency (C gene) and undesirable flavour traits. The following traits can be selected either in the field or in the greenhouse: yield potential (fruit size, number of fruit/plant, flesh thickness), plant height, regeneration ability, Susceptibility to Ca spots, white colour, basic colour of biologically mature fruit, determinate growth. Traits that can only be selected under controlled conditions: sensitivity to light deficiency, vertical resistance genes. An important practical rule for selection is that more costly techniques should only be applied after the number of plants has been reduced using cheaper selection methods.