Search Results (4)

Wheat is one of the main cereal crops for ensuring food supply. Thus, increasing grain yield is a major target for plant breeders, where insights into wheat productivity can be gained by studying the activity of the components of photosynthetic apparatus. The objectives of this study were to evaluate the agronomical performance of three winter wheat varieties and test photosynthetic efficiency over two different locations. Chlorophyll fluorescence was used to evaluate the maximum quantum yield of photosystem II (PSII) (TR₀/ABS) and performance index on absorption basis (PI_abs) of flag leaves and glumes of heads at the flowering stage until the mid-senescence stage. The grain yield of all varieties on average was significantly higher at Osijek compared to Tovarnik. Variety Tika Taka exhibited the highest yield reduction (27.1%) at Tovarnik compared to Osijek, followed by El Nino (20.5%) and Vulkan (18.7%), respectively. A higher amount of precipitation in June at Tovarnik provoked higher Fusarium head blight disease intensity, which could be seen as the bleaching of plant heads at the plots and resulted in an earlier decrease in photosynthetic activity. Therefore, earlier senescence and contracted grain fill duration could occur. Full article

New sources of resistance to fungal diseases, including FHB (Fusarium head blight), need to be identified. The results of research investigating ancient wheat species with desirable traits appear promising. The aim of this study was to determine the presence of Fusarium culmorum (W. G. Sm.) Sacc., F. graminearum Schwabe, F. poae (Peck) Wollenw, F. avenaceum (Fr.) Sacc. and F. langsethiae Torp & Nirenberg in the grain and glumes of diploid Triticum monococcum ssp. monococcum, tetraploid T. turgidum ssp. dicoccum, T. turgidum ssp. polonicum and T. turgidum ssp. durum, and hexaploid T. aestivum ssp. spelta and T. aestivum ssp. aestivum grown in north-eastern and south-eastern Poland and to analyze the trichothecene genotypes of the isolated strains. The results of this study also point to shifts in the genotype of Polish F. culmorum and F. graminearum populations from 3-ADON to NIV and 15-ADON to 3-ADON genotypes, respectively. Our findings indicate that selected einkorn lines could potentially be used as sources of genetic material for breeding new varieties resistant to FHB. The fungal genotypes should be closely screened in Poland and the neighboring countries to assess the effects of potential genotypes profile change on fungal virulence, toxin loading and host specificity. Full article

In recent decades, rice disease co-epidemics have caused tremendous damage to crop production in both China and Southeast Asia. A variety of remote sensing based approaches have been developed and applied to map diseases distribution using coarse- to moderate-resolution imagery. However, the detection and discrimination of various disease species infecting rice were seldom assessed using high spatial resolution data. The aims of this study were (1) to develop a set of normalized two-stage vegetation indices (VIs) for characterizing the progressive development of different diseases with rice; (2) to explore the performance of combined normalized two-stage VIs in partial least square discriminant analysis (PLS-DA); and (3) to map and evaluate the damage caused by rice diseases at fine spatial scales, for the first time using bi-temporal, high spatial resolution imagery from PlanetScope datasets at a 3 m spatial resolution. Our findings suggest that the primary biophysical parameters caused by different disease (e.g., changes in leaf area, pigment contents, or canopy morphology) can be captured using combined normalized two-stage VIs. PLS-DA was able to classify rice diseases at a sub-field scale, with an overall accuracy of 75.62% and a Kappa value of 0.47. The approach was successfully applied during a typical co-epidemic outbreak of rice dwarf (Rice dwarf virus, RDV), rice blast (Magnaporthe oryzae), and glume blight (Phyllosticta glumarum) in Guangxi Province, China. Furthermore, our approach highlighted the feasibility of the method in capturing heterogeneous disease patterns at fine spatial scales over the large spatial extents. Full article

A total of 122 wheat varieties obtained from the Nordic Genetic Resource Center were infected artificially with an aggressive Fusariumasiaticum strain in a field experiment. We calculated the severity of Fusarium head blight (FHB) and determined the deoxynivalenol (DON) content of wheat grain, straw and glumes. We found DON contamination levels to be highest in the glumes, intermediate in the straw, and lowest in the grain in most samples. The DON contamination levels did not increase consistently with increased FHB incidence. The DON levels in the wheat varieties with high FHB resistance were not necessarily low, and those in the wheat varieties with high FHB sensitivity were not necessarily high. We selected 50 wheat genotypes with reduced DON content for future research. This study will be helpful in breeding new wheat varieties with low levels of DON accumulation. Full article