Within temperate climates the frequency and severity of high and low temperature stresses vary with continentality. The current study reports on the assessment of the performance of 49 barley cultivars across four environments. The cultivars stem from 50 years of breeding activities in Romania and Italy, in two temperate climates that differ in continentality. The plants were phenotyped through stress monitoring, measurements of yield and yield related traits as well as laboratory stress tolerance tests. Genotypes for alleles of vernalisation and photoperiod genes were determined. These genes were significantly associated with frost damage in the field and frost tolerance in laboratory tests. Grain yield (GY) was more closely correlated with the number of grain sinks than with the degree of grain filling indicating major limitations in the vegetative growth phase and during grain initiation. High temperature stress during the grain filling phase significantly reduced GY. Frost damage due to freezing temperatures below −10 • C when plants were not protected by snow cover significantly reduced GY of sensitive cultivars. The characterisation of environmental cues that cause stresses with yield penalties as well as the susceptibility of genetically different cultivars lay the ground for future targeted selection.

During 2014-2016 at National Agricultural Research and Development Institute Fundulea three yield trials with winter barley cultivars under three levels of nitrogen fertilization were performed. The objective of this study was the evaluation of Romanian winter six and two row barley cultivars across three years, in order to analyse the effects of cultivar and fertilizer dose on yield and grain weight. As the main source of variation, the nitrogen level influenced significant the grain yield, which registered a progressive increase according to nitrogen dose, while the grain weight decreased from the second to third nitrogen level. Influence of grain weight on yield was different and much stronger in a few cases, comparing winter six row with two row varieties and their reaction to the nitrogen dose. Variations in grain weight were related to the number of row/spike and at the three levels of nitrogen fertilization were highly correlated (r = 0.93*** and 0.85***). The most productive winter six row varieties registered on average the lowest grain weight (Cardinal, Smarald and Lucian) and the highest yield. Winter two row variety Artemis and Gabriela presented an increased value of grain weight at 100 kg ha-1 nitrogen level and this quality index contributed to achieve higher yield.

Grain protein content (GPC) is the main quality trait of barley (Hordeum vulgare L.) because this parameter is a decisive component of seed quality for malt industry. Reaching the level of protein concentration required by the raw industry is very difficult, due to the negative correlation with the yield level. Seventeen winter barley genotypes (varieties and breeding lines), created at NARDI Fundulea during 2003-2017, known as having different grain protein contents, were tested with and without nitrogen fertilization in yield trials at NARDI Fundulea in 2014, 2015 and 2016. Weather conditions during the testing period was reflected by the variation of average yield of the trial from 3861 to 7722 kg/ha (unfertilized) and 4748 kg/ha to 9492 kg/ha (fertilized) and of the average grain protein content from 9.6% to 14.8% (unfertilized) and 10.3% to 15.4% (fertilized). Correlation between grain protein content and yield was significantly negative under unfertilized condition in two years (2014 and 2016) and under nitrogen fertilization in 2016 only. The genotypes with higher GPC in the grains and low yield under nitrogen fertilization are not adequate for use in breeding for improved protein content. Positive and negative deviations from the regression of grain protein content on grain yield were found, several varieties and lines combining high yields and high grain protein content and few varieties and lines combining high yields and low grain protein content. Differences between protein contents with and without nitrogen fertilization were smaller in some varieties and new lines and also presented negative deviations. The information obtained in this study might be useful in breeding new varieties combining low grain protein content and high grain yield.