Effects of Mild Temperature Stress on Grain Quality and Root and Straw Nitrogen Concentration in Malting Barley Cultivars

It is a challenge to obtain the appropriate protein concentration in cereals for the intended end-use. This study examined ambient temperature effects on two spring malting barley cultivars (Henley and Tipple) grown in soil or in solution culture with controlled nitrogen supply in daylight chambers with low temperature (day 18 degrees C, night 12 degrees C), and high temperature (23 degrees C/17 degrees C) to/after anthesis. In soil-grown plants, high temperature to anthesis resulted in higher grain nitrogen amount (GNA), grain nitrogen concentration (GNC) and straw nitrogen concentration (SNC). In plants grown in solution, high temperature to anthesis resulted in lower GNA and higher GNC. A temperature rise of 1 degrees C during the growing period in solution cultivation increased GNC, root nitrogen concentration (RNC) and SNC, by 1.20, 1.35 and 0.33 mg g(-1), respectively. In solution culture, GNC was positively correlated with RNC and SNC (P < 0.01). Cv. Henley had higher GNC but lower SNC than cv. Tipple. Cv. Henley was more stable in grain size and cv. Tipple in GNC. The results showed that temperature has a direct effect on GNC. Accounting for temperature fluctuations up to the latest possible nitrogen fertilisation occasion can therefore help when deciding appropriate nitrogen supply for intended end-use.