Studies on the Seed Production of Some Forage Grasses : I. On the suitable seed harvesting times of some grasses : II. On the tillering of orchard grass

Abstract

In harvesting seed of forage crops, the factors that make the determination of suitable time difficult are ; 1) the vigorous vegetative growth which covers the transition of the stage into reproductive phase ; 2) great individual difference due to the wide variation in cross pollinating plants which in turn makes such average periods as heading, blooming, and maturing lengthy. In the present report; the suitable seed harvesting times were studied with 13 gramineae grasses, and researches were made with orchard grass on tillering which has close relations with seed yield. (I) The average period from heading to harvesting stage of typical 13 grasses imported to Japan, were roughly classified into 3 grades as follows ; 1) less than 30 days ; 2) about 40 days ; 3) about 50 days or more. (II) There are found three peaks in the whole years curve of tillering of orchard grass, namely those in March, June, and Octover. In the first year, the largest part of the seed yield of orchard grass are obtained from the tillers of 1st, 2nd and 3rd orders, and the highest yield was from those of 2nd order. In the 2nd year, the major part of the yield was from the tillers of 4th, 5th and 6th orders, the 5th giving the highest yield. As to the fruitful tiller percentage, that of fall-midwinter tillers was relatively high, while it fell acutely in early spring tillers. Many of the main stems of orchard grass stopped growing in the midway. Even in those which headed and ripened, the seed yield was very small. From the comparison of the length of the tillering periods in the first year with that in the 2nd year, the latter was greatly found remarkably shorter making seed production technically more efficient.