Abstract
In Hokuriku, Japan, continous sterility in the lower spikelets of barley is observated. The results of the author's experiments were as follows : I. Plants sown at Sep. 25 produced more sterile spikelets than those sown at Oct. 20. II. The number of sterile spikelets increased by the treatment with high temperature, shading, long day, drought or high humidity of soil, in the period from snow-melting to heading. III. Cutting the leaf-blades the roots at the stage of flag-leaf emergence prmoted the sterility. IV. Top dressing with nitrogen fertilizers at the period from 15 to 7 days before heading (the stage of flag-leaf emergence) retarded the sterile spikelet developmant. V. Imperfect development of the pistle and degeneration or non-germination of the pollen were observed in the lower spikelets. Based upon these facts, authors considered that the inhibition of carbon assimilation or of absorption of nutriments at the above-mentioned period promoted the ocurrence of sterile spikelets owing to the imperfect development of the lower spikelets and that the top dressing favored, on the contrary their normal development.
