Drought damage, dwarf cereals, nitrogen application

Effects of drought on winter wheat  ​

Greenhouse experiments conducted by researchers at the Hungarian Academy of Science have revealed that drought stress at the heading or later phenophases of winter wheat development cause the greatest reduction in water use efficiency (WUE) values.

Considerable WUE differences were observed between cultivars and within the same cultivar (from 0.7 to 1.6 kg m−3), and were mainly due to environmental factors, they wrote in the Journal of Agronomy and Crop Science​.

While cultivars with short vegetation periods were more sensitive to drought at first node appearance, water deficit in the early phenophase only caused slight modifications in the yield components and WUE in later maturing cultivars.

In response to severe water deficit after heading, however, the plant water management was not regenerated even when water supplies were renewed.

Results demonstrated a close correlation between harvest index (HI) and WUE not only in the case of optimum water supplies but also in plants under stress.

Source: Journal of Agronomy and Crop science
Published online ahead of print: Doi: 10.1111/jac.12087​
‘Effect of Simulating Drought in Various Phenophases on the Water Use Efficiency of Winter Wheat’​​ 
Authors: B. Varg, G. Vida, E. Varga-Laszlo, S. Bencze, O. Veisz

Natural defence in dwarf cereal genotypes​

Scientists believe high cell densities found in shorter cereal genotypes provide a natural barrier against Fusarium Crown Rot (FCR).

FCR is one of the most damaging and prevalent pathogens in Australia, reducing yields and increasing production of harmful mycotoxins in cereals and vegetation.

Experiments revealed significant differences in seedling and cell length between tall and dwarf barley isolines: average seedling length for the two dwarf isolines was 23.2cm and 37.0cm for the two tall isolines was 37.0cm

The researchers could not identify the molecular mechanisms by which reduced plant height affects FCR development, but identified the uzu​ gene as the common denominator – responsible for reducing seedling length by an average 37.3% and cell length by 39.3%.

Results also suggest that tissues with higher cell density and reduced cell elongation may be more recalcitrant to cell wall breakdown, they wrote.

Source: Journal of Phytopathology
Published online ahead of print: Doi: 10.1111/jph.12283​ 
‘Histological Evidence for Different Spread of Fusarium crown rot in Barley Genotypes with Different Heights’​
Authors: Zhiying Bai, Chunji Liu

Effect of nitrogen fertilizers on phenolic concentrations​

Excessive application of nitrogen (N) fertilizers reduces the bioavailability of phenolic compounds in wheat, in addition to increasing production costs and environmental contamination, researchers claim.

The study investigated the affects of N fertilizers and grain maturity on total phenolic concentrations (TPC) on soft spring wheat treated with four different amounts of nitrogen and harvested at three different developmental stages (medium milk stage, late milk stage and dough maturity).

Researchers focused on free soluble, conjugated soluble and insoluble phenolic concentrations and discovered that TPC of free phenolic compounds rose with increasing N supply, while TPC of conjugated soluble phenolics decreased and remained more or less the same in insoluble phenolics.

Total phenolic concentrations peaked at the late milk stage.

Source: Journal of Plant Nutrition and Soil Science
Published online ahead of print: DOI: 10.1002/jpln.201400139​ 
‘Nitrogen fertilization and maturity influence the phenolic concentration of wheat grain (Triticum aestivum)’ ​
Authors: Beate Stumpf, Feng Yan, Bernd Honermeier