Combining ability analysis of fusarium head blight resistance in European winter wheat varieties

The aims of the present study were to estimate the general combining ability (GCA) and the specific combining ability (SCA) effects controlling type II FHB resistance across environments in a set of European winter wheat varieties and, for purposes of future selection, to identify potential combinations of parents with suitable levels of FHB resistance. Parental varieties as well as F1 generations were evaluated under both field and greenhouse conditions in two years. The results of the present study indicate that in the F1 generation mean DON content was relatively lowest after crossing of moderately resistant parents (Sakura/Bakfis, Sakura/Federer, Petrus/Bakfis, and Sakura/Petrus), and mean DON content is low also after crossing the moderately resistant Bakfis variety with the susceptible Biscay and Cubus varieties. Evaluation of crosses in the F1 generation was followed by evaluation of selected crosses (derived from the Bakfis and Sakura varieties) in the F2 generation. Correlations between F1 and F2 were highly significant in relation both to their DON content and visual symptom score (VSS), as well as between the individual experiments (and in the different years). The only exception was in the case of the 2014 field experiment, when inoculation was successful but conditions were not optimal for the disease to progress and DON to accumulate. The selection of a suitable parental variety (with a high GCA) can markedly influence the success rate of breeding for resistance to FHB. Detection of high SCA in the F1 generation is important for directing breeders to promising combinations for achieving FHB resistance. It was demonstrated here that low DON content may be achieved even after crossing a moderately resistant variety with susceptible varieties. Another possibility is to make use of heterosis directly for acquiring resistance in hybrid wheat (for decreasing DON content and manifestation of symptoms)

The concept of tacit knowledge in the paradigm of a unified field

Cílem teoretické studie je vyjasnit pojetí tacitních znalostí (TZ). V první části autoři ukazují, v čem tkví hlavní problém současného diskurzu o tacitních znalostech. Jestliže budeme vnímat znalost jako mentální reprezentaci, nemůžeme náležitě pochopit a zkoumat TZ. Ve druhé části za pomocí příkladů z děl J. Deweyho a J. Piageta autoři dokládají, že zde již jedno století existuje alternativní – funkcionální – pojetí znalosti. Třetí část se zaměřuje na definice znalosti a poukazuje na fakt, že problematika takových definic spočívá v tom, že pedagogové a epistemologové nerozhodně stojí mezi tradičním a alternativním paradigmatem (v textu pracovně nazývaných: „paradigma oddělených objektů“ a „paradigma sjednoceného pole“). To vede k mnohým nesrovnalostem v jednotlivých teoriích a k jejich malé použitelnosti v praxi. Ve čtvrté části autoři představují epistemologické pozadí tradičního paradigmatu, aby v části páté poskytli popis pozadí paradigmatu alternativního. Díky tomuto postupu jsou v závěrečné části autoři schopni definovat alternativní pojetí TZ. Docházejí zde ke zjištění, že znalost musíme vnímat jako dynamickou strukturu sjednoceného pole a TZ chápat jako tacitní dimenzi dynamické struktury (TDZ). Teprve takto pochopená tacitní znalost nám umožňuje zkoumat její dimenze.The aim of this theoretical study is to clear the concept of tacit knowledge. In the first part of the text, the authors show where the confusion comes from. If we take knowledge as a mental representation we will not, in fact, be able to inquire it. In the second part, an alternative, which has been alive for more than a hundred years, is detected in works on knowledge and knowing by scholars such as Dewey and Piaget. Then, in the third part, the authors depict the hesitation of specialists that could not abandon the old traditional understanding of knowledge (in the study connected with the “paradigm of separated objects”) and their need to across it. Thus they stay between the old and the new paradigm (the new one is in the text referred to as the “paradigm of a unified field”) and therefore, their theories are very often confusing and unusable in praxis. For better understanding of the two – traditional and alternative – paradigms, the authors off er a short introduction to both in the fourth and fifth parts. The study ends by the conclusion that if we are able to understand knowledge not as a representation, but as a dynamic structure of a unified field, we will be able to grasp tacit knowledge as a tacit dimension of the structure and thus we will be able to study it more properly

Evaluation of Fusarium head blight resistance in wheat under high infection pressure in field conditions

Resistance of 28 winter wheat cultivars registered in the Czech Republic and ten potential sources of resistance to Fusarium head blight (FHB) was evaluated after artificial inoculation with Fusarium culmorum in field trials lasting for three years (2008, 2009, 2010). The data on deoxynivalenol (DON) content were supplemented by symptom scores and determination of% of Fusarium damaged grains and% reductions of grain weight per spike due to infection. The examined traits were significantly interrelated and showed high variation in all years. Significantly lower DON content, combined with relatively lower manifestation of the disease was observed in the modern, commercially grown cultivars Bakfis, Graindor, Sakura and Bodycek (catalogued in the Official Journal of EU), besides Novokrymka 102, PI 166910 (line resistant to dwarf and common bunt) and Arina, which could be effectively used in resistance breeding. However, the experiments performed under high infection pressure were also able to reveal high susceptibility to FHB in some commercially grown wheat cultivars, which may pose a serious threat to wheat production

Content of fusarium-mycotoxins in some spring barley varieties (artificial and natural infection).

A quantitative immunochemical technique ELISA was used to determine DON content in samples of spring barley varieties inoculated by Fusarium culmorum in 2000 (12 varieties) and 2001 (19 varieties). DON content in the samples from 2000 crop ranged from 5.1 (Forum) to 19.1 ppm (Jersey) with average 9.7 ppm while the range of DON content in 2001 crop was from 1.3 (Madeira) to 8.2 ppm (CI.4196) with average 3.8 ppm. DON content was also determined in another set of 32 samples of spring barley varieties from fields in 24 districts of the CR from 2001 crop and a mycological examination was made using the method of mycologically monitored grains to identify the species of fungal pathogen. ELISA detected DON in all samples of this set; its content ranged from 0.03 to 3.77 ppm, average content was 0.4 ppm, the limit value was exceeded in one sample only. Fusarium graminearum was a prevailing toxicogenic species in spring barley in 2001; its capture coincided with higher levels of DON. It was stated that ELISA and GC were compatible methods for DON determination.A quantitative immunochemical technique ELISA was used to determine DON content in samples of spring barley varieties inoculated by Fusarium culmorum in 2000 (12 varieties) and 2001 (19 varieties). DON content in the samples from 2000 crop ranged from 5.1 (Forum) to 19.1 ppm (Jersey) with average 9.7 ppm while the range of DON content in 2001 crop was from 1.3 (Madeira) to 8.2 ppm (CI.4196) with average 3.8 ppm. DON content was also determined in another set of 32 samples of spring barley varieties from fields in 24 districts of the CR from 2001 crop and a mycological examination was made using the method of mycologically monitored grains to identify the species of fungal pathogen. ELISA detected DON in all samples of this set; its content ranged from 0.03 to 3.77 ppm, average content was 0.4 ppm, the limit value was exceeded in one sample only. Fusarium graminearum was a prevailing toxicogenic species in spring barley in 2001; its capture coincided with higher levels of DON. It was stated that ELISA and GC were compatible methods for DON determination

AFLP genotyping improves the level of discrimination between the Fusarium species responsible for head blight in wheat

Amplified fragment length polymorphism (AFLP) analysis was applied to genotype 186 Czech isolates of the Fusarium species responsible for head blight disease in wheat. Using 15 primer combinations, 694 polymorphic fragments were detected. The effective number of patterns was dependent on both the identity of the selective primer combination and on which Fusarium species was involved. The most informative primer combinations were CAT + AT, CAT + AC and CTA + AG, and a triplex assay based on CAT was able to distinguish all 186 isolates from each other. A principal component analysis identified six phylogenetic clusters, and this genetic architecture was supported by an analysis of population structure. AFLP profiling is an appropriate method for uncovering differences between these groups of Fusarium species