Appearance of Tillers Stimulated with Additional Topdressing at Late Growth Stage for Naked Barley Cultivar “Kirarimochi” and Influence of Large Amount of Topdressing at Tillering Stage

Abstract

In barley cultivar “Kirarimochi”, many premature tillers are observed at harvesting while the grain yield and spike number increase with additional topdressing at later growth stages. The amount of nitrogen fertilizer applied was 4 g m^–2 at pre-sowing, 2 g m^–2 at tillering stage, 6 g m^–2 at spike formation stage and 6 g m^–2 at anthesis (4-2-6-6). The appearance of many tillers at the early growth stage might inhibit the late emerging tillers from appearing. The amount of topdressing at the tillering stage was increased and topdressing at the spike formation stage omitted (4-8-0-6) in order to make the tillers productive earlier. Tiller number and spike number were counted by fixed point observation to determine whether the tillers become productive or non-productive. Grain yield, yield components and total weight for 4-8-0-6 were not different from those in 4-2-6-6. The 8 g m^–2 of nitrogen topdressing at the tillering stage, 4-8-0-6, did not increase the number of tillers compared with 2 g m^–2 in 4-2-6-6. Spike number at harvest was twice that at anthesis both in 4-2-6-6 and 4-8-0-6. Many spikes appeared from two weeks after anthesis in 4-8-0-6. The distribution of culm length was bimodal. There were many spikes with a culm length less than 600 mm in 4-2-6-6 and 4-8-0-6.