抄録
Experiment was carried out in 1950 on the varietal difference of the effect of short day-length upon the ripening period of soy-beans. Vaiieties used were Kisaya (Kagoshima), Norin No. 2(Ibaragi) and lwate No. 2 (Iwate). The plants were grown in soil by pot culture and the half oi them were treated with 8 hours day'length, from 8 a.m. to 4 p.m, every day, durin.g the period fronl bloommg to, maturity. Other half of them were left under natural day-length. The results are summartized as follows : (1) Apparen responses of ripening period to the short day treatment were observed. Yellowing and hedding of leaves and nlaturity " were acceleratedby short photoperiod and consequently the piriod from blooming to ripening of pods becon):es shorter. The acceleratton was remarkably larger in variety STE:12q:ERG, R. A. and GARNER, W. W. (1936) : Response of certain plants to length of day and temperture under controlled con: dition. Jour Agric. Res. 52 (12) 94-960 of long ripening period (lwate No. 2) than variety of short ripening, period (Kisaya) .(2) The growth of p. ods was accelerated by short photoperiod, but the varietal difference of this effect was not discussed becal;se the measurement was made too late. Weight and shape of seeds were also effected by short-day tratment. Weight of seed, length, thickness and wideness of seeds were maller in treated plots than control plots. This trend was less obvious in Kisaya, but obvious in varieties Norin No. 2 and lwate No. 2. (3) These facts will be useful to explain the distribution of soy-bean varieties and further to select the stlitable varieties at any place or to make soy-bean breeding. Moreover the facts will be availetble for the ecologicai interpretation of so-called seed-home of soy-beans.
