Changes in time of sowing, flowering and maturity of cereals in Europe under climate change.

The phenological development of cereal crops from emergence through flowering to maturity is largely controlled by temperature, but also affected by day length and potential physiological stresses. Responses may vary between species and varieties. Climate change will affect the timing of cereal crop development, but exact changes will also depend on changes in varieties as affected by plant breeding and variety choices. This study aimed to assess changes in timing of major phenological stages of cereal crops in Northern and Central Europe under climate change. Records on dates of sowing, flowering, and maturity of wheat, oats and maize were collected from field experiments conducted during the period 1985-2009. Data for spring wheat and spring oats covered latitudes from 46 to 64°N, winter wheat from 46 to 61°N, and maize from 47 to 58°N. The number of observations (site-year-variety combinations) varied with phenological phase, but exceeded 2190, 227, 2076 and 1506 for winter wheat, spring wheat, spring oats and maize, respectively. The data were used to fit simple crop development models, assuming that the duration of the period until flowering depends on temperature and day length for wheat and oats, and on temperature for maize, and that the duration of the period from flowering to maturity in all species depends on temperature only. Species-specific base temperatures were used. Sowing date of spring cereals was estimated using a threshold temperature for the mean air temperature during 10 days prior to sowing. The mean estimated temperature thresholds for sowing were 6.1, 7.1 and 10.1°C for oats, wheat and maize, respectively. For spring oats and wheat the temperature threshold increased with latitude. The effective temperature sums required for both flowering and maturity increased with increasing mean annual temperature of the location, indicating that varieties are well adapted to given conditions. The responses of wheat and oats were largest for the period from flowering to maturity. Changes in timing of cereal phenology by 2040 were assessed for two climate model projections according to the observed dependencies on temperature and day length. The results showed advancements of sowing date of spring cereals by 1-3 weeks depending on climate model and region within Europe. The changes were largest in Northern Europe. Timing of flowering and maturity were projected to advance by 1-3 weeks. The changes were largest for grain maize and smallest for winter wheat, and they were generally largest in the western and northern part of the domain. There were considerable differences in predicted timing of sowing, flowering and maturity between the two climate model projections applied.

[Not Available]. / Shifting von Fusarienarten und ihren Toxinen in österreichischem Getreide.

Based on representative analyses of Austrian cereals, a distinct shift in the spectrum of Fusarium toxins and Fusarium species has been observed since the middle of the eighties.Although in the case of maizeF subglutinans - apart fromF graminearum - proved to be the most frequent and constant contaminant over the entire range of test series, there has been a shift in the spectrum of species which is not to be explained simply by seasonal variations or by the varying degree of occurrence of the European corn borer, which in Austria is considered to be the main vector for infections involving fusaria of the Liseola section. Compared to the results from earlier vegetation periods, the nineties brought a significant increase in the number of infections withF proliferatum, a fumonisin-producer. In all likelihood, this shift in the spectrum of species is due to the changed climatic conditions now prevailing in Austria - milder and more humid winters vs. drier and warmer summers - which favour the progress ofF proliferatum.The principal toxin-forming fungus on cereals in Austria isF graminearum. On maize, its respective populations are exclusively those which produce 15-acetyl-DON as a precursor to DON (deoxynivalenol). Whilst in the 1980s,F graminearum isolates from wheat yielded both 15-acetyl-DON and 3-acetyl-DON types, only 15-acetyl-DON populations could be detected in the last few years. One possible explanation for this phenomenon is the continual intensification of maize-wheat crop rotations. In the light of the above observations, the frequently used argument whereby EuropeanF graminearum isolates produce mainly 3-acetyl-DON and American strains prevalently 15-acetyl-DON will have to be reviewed.

Occurrence of moniliformin, deoxynivalenol, and zearalenone in durum wheat (Triticum durum Desf.).

Forty-eight durum wheat samples from 5 locations in Austria were examined forFusarium infection andFusarium toxin content.F.gramlnearum andF.avenaceum were by far the prevailingFusarium species In durum wheat kernels, followed byEpoae, F.culmorum, andF.equlsetl. Ion-paired HPLC analyses of the samples showed moniliformin contents of kernels up to 0.88 mg/kg. All moniliformin contaminated samples also contained high levels of deoxynivalenol (up to 8.2 mg/kg) and lower levels of zearalenone (<0.33 mg/kg). The levels of zearalenone in naturally contaminated durum wheat samples did not correspond to the high yields of zearalenone found in cultures of the fusaria isolated from the durum wheat kernels. These conflicting results as well as some toxicologlcal aspects of the carry over ofFusarium toxins from durum wheat kernels into pasta are discussed.