This paper presents data on the effects of winter weather on flowering and fruiting of Prunus mume.
The results obtained are as follows;
(1) Critical temperature for flower killing was -8.0°C--9.5°C, and air temperature near -4.5 °C--5.0°C was found to be critical for killing young fruits of Prunus mume.
(2) MIURA (1962) reported that the percentage of fruit set of Koume variety was high when the daily maximum temperature reaches more than 15°C.
(3) It would be desirable to cultre Prunus mume at the meteorologically suitable place where the minimum air temperature as low as -8.0°C--8.5°C in flowering stage and -4.5°C--5.0°C in the young fruits stage do not occur frequently, together with higher daily temperature in the flowering stage.