Cultivation method for high-quality and stable yield for the two-rowed malting barley 'Sukai Golden'

We studied the growth characteristics of the two-rowed malting barley 'Sukai Golden' and the factors necessary for full development of its varietal characteristics, including levels of fertilizer application, sowing density, and row distance. The following results were obtained from a three-year-long test of various levels of nitrogen fertilizer and sowing densities. 'Sukai Golden' and 'Mikamo Golden' had similar grain weights, but the former had a higher plump-grain percentage than the latter. 'Sukai Golden' had a distinctly higher content of grain crude protein than 'Amagi Nijo'. 'Sukai Golden' and 'Mikamo Golden' had similar levels of grain crude protein. These two cultivars also had similar responses to fertilizer application. The crude protein content in grains of 'Sukai Golden' was strongly affected by the amount of applied nitrogen fertilizer and by the sowing density. The crude protein content showed a tendency to decrease at low levels of fertilizer application (e.g., 6.5 kg N/10 a) and at high sowing densities (e.g., 238 seeds/m(2)). At the same time, low level application of fertilizer induced a marked decrease in the number of spikes, and the grain weight was also decreased. High sowing density decreased the number of grains per spike, 1000-grain weight, and plump-grain percentage; thus, the varietal characteristics of 'Sukai Golden' were not fully expressed under these conditions. Based on these results, a fertilizer application of 8 kg N/10 a and a sowing density of 192 seeds/m(2) were best for suppressing the level of grain crude protein, and at the same time maintaining high plump-grain percentage and high yield in 'Sukai Golden'. However, as the test plots used in our study were relatively infertile, we recommend a fertilizer level of 5.5-6.5 kg N-10 a when cultivating 'Sukai Golden' in ordinary fields, a level similar to that used for 'Mikamo Golden'.