Studies on the Germination of Barnyardgrass Seeds : 2. On the germination of barnyardgrass seeds stored for various days after harvest.

Abstract

Seeds were harvested from 15 varieties of Echinochloa crusgalli L., 1 strain of E. c. Beauv. var. formosensis Ohwi, 3 strains of E. c. Beauv. var. oryzicola Ohwi, 2 strains of E. c. Beauv. var. praticola Ohwi and 2 strains of E. c. Beauv. var. caudata Kitagawa immediately after reaching maturity and then were stored in paper bags for 20, 40, 60, 80 and 100 days, respectively. By using such seeds, the percentage of germination, velocity of germination and dormancy were examined in a thermostat at 30°C. The results obtained were as follows: 1. The percentage of germination of Echinocloa crus-galli L. (cultivated species) was very higher than that of the 4 wild species. The differences of the percentage were not significant among varieties. Generally speaking, the percentage was not affected by the number of storage days. But the percentage of the 4 wild species ranged from 14.4% (shown by the strain of E. c. Beauv. var. caudata Kitagawa) to 62% (shown by the other strain of E. c. Beauv. var. caudata Kitagawa) and the wild species could be divided into the following 3 groups from the relation of the percentage to the number of storage days. That is, the percentage of the first group constituted from the 2 strains of E. c. Beauv. var. caudata Kitagawa increased with the increase of storage days and the second group constituted from the 1 strain of E. c. Beauv. var. oryzicola Ohwi collected from the Hokuriku National Agricultural Experiment Station showed the decrease of the percentage with the increase of storage days. With the third group, the percentage increased up to the eightieth day from the beginning of storage, but the percentage when stored for 100 days lied between both cases of 80 days and 60 days. 2. From the above percentage of the strains of wild species, the beginning dates of awakening for both primary dormancy and the secondary dormancy were discussed. 3. There was no difference of velocity of germination among the cultivated varieties and the velocity of these varieties was larger than that of the wild species. The velocity of E. c. Beauv. var. oryzicola Ohwi differed greatly each other among the strains, but the differences of velocity among the strains of both E. c. Beauv. var. praticola Ohwi and E. c. Beauv. var. caudata Kitagawa were small. The number of storage days had no decisive influence upon the velocity of germination.