Timely and reliable prediction of grain yield and quality of spring barley represents a key prerequisite for effective crop management. Within this study we evaluated the relationships between yield components, grain quality, biomass production and the number of tillers in different growth stages. For this purpose, in three years (2011)(2012)(2013) multifactorial field trials focused on the combined effects of cultivar, sowing density and nitrogen nutrition were conducted. Based on ANOVA it was found that the formation of grain yield was affected by individual factors in the following order of importance: year, nitrogen, cultivar and sowing rate. The final grain yield significantly correlated both with the number of tillers and dry weight of above-ground biomass per unit area. The best estimation of yield provided both parameters at early growth stage (R = 0.83** and 0.81** for number of tillers and the above-ground biomass at BBCH 25). The grain protein content was inversely related to early growth parameters (R = -0.64** and -0.41** for number of tillers and above-ground biomass at BBCH 25). Based on the comparison of relationships between the years, it can be concluded that the early growth of barley and tiller differentiation is a key parameter for the formation of yield and grain quality.

Reverse transcription coupled with real-time quantitative PCR (RT-qPCR) is a frequently used method for gene expression profiling. Reference genes (RGs) are commonly employed to normalize gene expression data. A limited information exist on the gene expression and profiling in developing barley caryopsis. Expression stability was assessed by measuring the cycle threshold (Ct) range and applying both the GeNorm (pair-wise comparison of geometric means) and Normfinder (model-based approach) principles for the calculation. Here, we have identified a set of four RGs suitable for studying gene expression in the developing barley caryopsis. These encode the proteins GAPDH, HSP90, HSP70 and ubiquitin. We found a correlation between the frequency of occurrence of a transcript in silico and its suitability as an RG. This set of RGs was tested by comparing the normalized level of β-amylase (β-amy1) transcript with directly measured quantities of the BMY1 gene product in the developing barley caryopsis. This panel of genes could be used for other gene expression studies, as well as to optimize β-amy1 analysis for study of the impact of β-amy1 expression upon barley end-use quality.

439Water deficit is a stress factor whose implications very often lead towards the decrease in agriculture production. Current climatic changes induce not only dramatic fluctuations of the temperature, but as well as relatively non-uniform, irregular and random distribution of precipitation during the growing season. Considering these facts, a longer period of drought cannot be omitted either. Along with the increasing atmospheric CO 2 concentration and raising temperature in continental regions, water deficit is one of the most discussed elements of global climatic changes.Data obtained from meteorological stations in south Moravia from 1961 to 1990 aiming at the frequency of dry periods were analysed by Rožnovský (1998). He indicates that dry periods were found in more than 20% of the growing seasons. Thus we have to take into consideration that each two years from ten, precipitation sums in April and May will not exceed 20 mm. If we consider assumed climatic changes, an increasing number of dry periods can be envisioned. To complete these data, results from observations of the meteorological station at Kroměříž for the period of 1996-2003 can be added. The periods without precipitation longer than 6 days in April and May were found almost in each of these years (and more than once), periods longer than 11 days in three years.Effects of water deficit on plants were studied at various levels (structural and functional) from ecophysiology up to cell metabolism. In cereal crops, a number of research studies have dealt with responses and adaptations of wheat and barley genotypes (for instance, Zemánek 1991Zemánek , Švihra et al. 1996, others focused rather on the effect of water shortage than on plant growth and development, and yield formation. The effects of water deficit on plants depend on the stage of its ontogenetic development and duration of this stress factor. As Brestič (1996) reports, alleviation of drought implications can be highly effective for grain yield, nevertheless, possibilities of improving the status of the plants under water stress are limited. Of yield elements, the water stress before wheat anthesis causes the highest decrease in grain number per spike (Ali et al. 1999, Foulkes et al. 2002, and reduction in a number of developed tillers (Cabeza et al. 1993). In spring barley, drought affects a spike number Effect of drought stress on the formation of yield elements in spring barley and the potential of stress expression reduction by foliar application of fertilizers and growth stimulator I. Svobodová, P. Míša Agricultural Research Institute Kroměříž, Ltd., Czech Republic ABSTRACTSpring barley plants were exposed to water stress at different growth stages -from the period a�er emergence to the beginning of stem elongation, from emergence to the end of anthesis and from the beginning of stem elongation to the end of anthesis in pot experiments. In variants exposed to water deficit from emergence to the end of anthesis and from the beginning of stem elongation to the end of anthesis, effect...

ABSTRACT:Mapping of the with-in field variability of crop vigor has a long tradition with a success rate ranging from medium to high depending on the local conditions of the study. Information about the development of agronomical relevant crop parameters, such as aboveground biomass and crop nutritional status, provides high reliability for yield estimation and recommendation for variable rate application of fertilizers. The aim of this study was to utilize unmanned and satellite multispectral imaging for estimation of basic crop parameters during the growing season. The experimental part of work was carried out in 2014 at the winter wheat field with an area of 69 ha located in the South Moravia region of the Czech Republic. An UAV imaging was done in April 2014 using Sensefly eBee, which was equipped by visible and near infrared (red edge) multispectral cameras. For ground truth calibration the spectral signatures were measured on 20 sites using portable spectroradiometer ASD Handheld 2 and simultaneously plant samples were taken at BBCH 32 (April 2014) and BBCH 59 (Mai 2014) for estimation of above-ground biomass and nitrogen content. The UAV survey was later extended by selected cloud-free Landsat 8 OLI satellite imagery, downloaded from USGS web application Earth Explorer. After standard pre-processing procedures, a set of vegetation indices was calculated from remotely and ground sensed data. As the next step, a correlation analysis was computed among crop vigor parameters and vegetation indices. Both, amount of aboveground biomass and nitrogen content were highly correlated (r > 0.85) with ground spectrometric measurement by ASD Handheld 2 in BBCH 32, especially for narrow band vegetation indices (e.g. Red Edge Inflection Point). UAV and Landsat broadband vegetation indices varied in range of r = 0.5 -0.7, highest values of the correlation coefficients were obtained for crop biomass by using GNDVI. In all cases results from BBCH 59 vegetation stage showed lower relationship to vegetation indices. Total amount of aboveground biomass was identified as the most important factor influencing the values of vegetation indices. Based on the results can be assumed that UAV and satellite monitoring provide reliable information about crop parameters for site specific crop management. The main difference of their utilization is coming from their specification and technical limits. Satellite survey can be used for periodic monitoring of crops as the indicator of their spatial heterogeneity within fields, but with low resolution (30 m per pixel for OLI). On the other hand UAV represents a special campaign aimed on the mapping of high-detailed spatial inputs for site specific crop management and variable rate application of fertilizers.

The processes of stand structure and yield formation of spring barley were studied under different weather conditions and crop management. The multifactorial small-plot trials focused on the combined effect of variety, sowing density and nitrogen nutrition were carried out in two years with contrast weather conditions for yield formation (2011 and 2013). Evaluation of the above-ground biomass and the segmentation of tillers into three groups was conducted in four growth stages (BBCH 25, 31, 39 and 75). The performed analyses confirmed that for effective use of inputs and high yield, it is important to create a sufficient number of strong tillers at the beginning of vegetation. In year with low proportion of strong tillers at the end of tillering (2013), the differentiation of tillers is delayed and their productivity decreases. In this year therefore, yield formation is shifted from the number of spikes to the number of grains in a spike. The comparison of barley genotypes revealed that high yield plasticity can be obtained especially in the variety Bojos, which is able to compensate effectively the changes in spike number by increased grain number in a spike. This variety is also able to create a high proportion of strong tillers even under unfavourable conditions. This knowledge could help to improve the breeding and management strategy in spring barley for the expected weather conditions in the near future, especially higher temperatures in early spring.