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Osmotické přizpůsobení rekombinantních linií ječmene jarního s vyšší tolerancí k suchu a jeho hodnocení v polních podmínkách
Baláž, David
The thesis deals with the role of drought and the effects on growth, morphology and yield of barely. The evaluation of the physiological mechanisms at the level of the osmotic adjustment of plants was done at two locations differing in the soil water regime. These mechanisms were studied on a group of 20 recombinant inbred lines (RIL) derived from crosses between spring barley Jersey (spring malting cultivar) and Syrian landrace Tadmor, which was used as a donor of drought tolerance. The progeny derived from reciprocal crosses were evaluated for yield parameters (thousand grain weight, grain yield per plant, the proportion of grains over 2 mm) and qualitative parameters (starch content and nitrogen content). The physiological status of the plants was evaluated using relative water content, osmotic potential (OP) and proline content as an osmotically active substance. The effect of location on all above mentioned parameters was estimated on parental varieties as well as on RIL lines. According to the results several lines were selected which exhibit relatively high stability of yield and qualitative parameters at both locations. The relationship between the yield parameters and values associated with the mechanism of osmotic adjustment (RWC, OP and proline content) was not clearly demonstrated. Decrease of OP and increase of proline content in plants cultivated under dry conditions at location Žabčice mostly corresponded to increased level of plant wilting, therefore it is possible that only passive mechanism for OP was involved. This mechanism did not affect the drought tolerance.
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Hodnocení potenciálních donorů vyšší odolnosti k suchu u pšenice ozimé
Prokešová, Lenka
This work summarises the results of experiments with common wheat lines (T. aestivum L. emed. Fiori et Paol.) during the growing season 2013/2014. Field experiments were carried out in two locations -- Žabčice and Branišovice. Two winter wheat varieties (Etela and Meritto) commonly cultivated in the Czech Republic and 45 Syrian lines with potentially high drought tolerance were evaluated in this work as well as Syrian variety CHAM 6. Spikes analyses were performed and the evaluated characters included awn length, spike length, spike weight, spikelet number, rachis length, rachis segments number, grains per spike number, and grains per spike weight. We focused also on grain yield per plant and the weight of thousand grains. The effect of location was highly significant for both characters -- yield per plant was higher in Žabčice, thousand grain weight in Branišovice. Two quality indicators were assessed -- the content of proteins and starch. As to protein content, all lines and control varieties exceeded the standard given in ČSN 461100-2. The amount of starch was between 66 and 68 %. The response to day length was characterised according to the photoperiod loci Ppd-D1. Photoperiod insensitive allele Ppd-D1a was more common in lines of Syrian origin than sensitive allele Ppd-D1b. To evaluate the tolerance to drought the osmotic potential was determinated and the greatest ability of osmotic adjustment was found in line 27/1.
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Hodnocení experimentálních linií ječmene z hlediska tolerance k suchu a rezistence vůči padlí
Slabá, Veronika
Drought is considered as one of the most important abiotic stress factor, which can cause a severe impact on agriculture. The development of new cultivars of barley is therefore more focused on improving of abiotic stress tolerance to drought, as well as on maintaining of good health status, appropriate yield levels and quality parameters. This work was aimed at evaluation of barley cv. Tadmor, which is specifically adapted to drought and can be potentially used as a source of drought tolerance in barley breeding programmes. F5 generation lines derived from reciprocal crosses between cv. Tadmor and cv. Jersey (advanced European spring malting barley) together with parent cultivars were cultivated at two sites (Brno, Žabčice). The assessment was aimed at traits associated with yield (thousand grain weight - TGW, percentage of sieving fraction over 2.0 mm, grain yield per plant) and quality (protein and starch content). The effect of water-limited conditions at Žabčice site was demonstrated particularly in the TGW and the percentage of sieving fraction over 2.0 mm, while the lines from Tadmor x Jersey cross sustained the stress significantly better than those from Jersey x Tadmor cross. The lines grown in Žabčice reached in average a higher level of protein content and a lower level of starch content. The significant effect of genotype was detected only in protein content and was non-significant for starch. The reaction of selected lines on osmotic stress was studied in and independent experiment under controlled conditions. The plant stress reaction was evaluated according to changes in osmotic potential in leaves and accumulation of proline. Lines with Tadmor as a female parent showed higher values of osmotic potential in comparison with those derived from the reciprocal cross. The increase in osmotic potential under stress was strongly associated with the content of proline. The last part was focused on evaluation of susceptibility to powdery mildew caused by Blumeria graminis. The symptoms of powdery mildew on experimental lines were assessed in field and the lines, which were classified as resistant/susceptible, were further analysed for the presence of mlo allele. According to the results all resistant lines carried mlo9. With regard to all evaluated parameters, positive reaction on physiological drought stress and genetically controlled resistance against powdery mildew two lines can be recommended for further work.
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