Study on the Ripening Process of Two-Rowed Barley

Abstract

In 1963, "Kanto two-rowed .Barley No. 2" crop was seeded on the upland farm of alluvial sandy-loam soil, and grown with usual cultural methods. Changes .in the size .and weight as well as in a few chemical components of barley kernels were traced at 5-day intervals after the full heading stage. The temperatures and sunlight intensity during the ripening period in the year were somewhat above in the normal. The results are given below. (1) Panicle weight was on a rapid increase for 30 days after full heading, but the increasing rate for the former 10 days was lower than that for the latter 20 days. Panicle weight increased slightly from the 30 th day after full heading up to the ripening stage. (2) Kernel length was on a very rapid increase for 10 days after full heading, but in the first half period the rate of elongation of kernels was higher. For the subsequent 5 days it increased, reaching a peak on about the 15 th day after full heading. After that almost no change in the length was observed. The width of kernels was on the increase up to about the 25 th day after full heading. Thereafter, it increased slightly up to the ripening stage. The thickness of kernels increased for the period from the 5 th day to the 35 th day after full heading, but the increasing rate was higher in the former half-period than in the latter half. Afterwards it continued. to show a slight increase up to the ripening stage. (3) The grains more than 2.5 mm in diameter began to appear from about the 20 th day after full heading. No. 1. grain ratio reached the standard value on about the 30th day to the 35 th day after full heading. (4) 1, 000 kernel weight showed a rapid increase from the 10 th days about the 30 th day after full heading, reaching a peak at about the stage between the 35 th day to the 40 th day after full heading. Thereafter, it decreased slightly. Almost similar trend was observed in respect of the kernel weight per liter. (5) Hull weight ratio showed a rapid decrease up to about the 20 th day after full heading. Thereafter, it decreased slightly, reaching the minimum on around the 35th day after full heading. (6) Crude-protein content showed a rapid decrease from about the 10 th day after full heading, reaching the minimum on about the 25th day after full heading. Thereafter, crude-protein content increased up to about the 40 th day after full heading and thence it showed a slight decrease again. (7) Starch value showed a rapid increase for 20 days from the 5 th day after full heading. Afterwards, it increased slightly. (8) Crude fat content increased slightly after full heading, reaching the maximum on about the 30th days after full heading. Thereafter, almost no change was observed. (9) Ash content decreased from around the 5 th days after full heading, reaching the minimum on about the 30 th day. Afterwards almost no change was observed. From the above results, it was evidenced that the ripened grains being about the 35 th day to the 40th day after full heading showed the highest yield and quality.