Two seedy cultivars, male sterile 'Sweet Spring' and self-incompatible 'Otachibana', were pollinated with soft-X-irradiated pollen to produce seedless fruit. Pollen irradiated with a dose of 510 or 720 Gy were used to pollinate 'Sweet Spring'. The rate of fruit set was low with soft-X-irradiation compared with non-irradiation. Fruit with soft-X-irradiation were slightly smaller than those with non-irradiation. All fruit were seedless with soft-X-irradiation. The other fruit traits were little affected by pollination with soft-X-irradiated pollen. Doses of 510 and 720 Gy led to almost the same results. In 'Otachibana', pollen irradiated with 510, 720, or 1000 Gy were used for pollination. There was no significant difference between the rate of fruit set with soft-X-irradiation and that of non-irradiation. Fruit with soft-X-irradiation were smaller than those with non-irradiation. Almost all fruit were seedless with soft-X-irradiation. The other fruit traits were little affected by pollination with soft-X-irradiated pollen. Differences in dose little affected almost all traits. Flowers on an entire whole tree which was enclosed by a net to exclude insect visitors were pollinated with soft-X-irradiated pollen. Numbers of harvested fruit were almost the same with soft-X-irradiation and non-irradiation. Almost all harvested fruit were seedless. Thus, this method is considered to be useful for seedless fruit production in 'Otachibana'.

View full abstract

In this study of the cultivation of winter-cropped lettuce following paddy rice, a tendency for higher ridge surface temperature was observed when mulching was performed after ridging with an up-cut rotary tiller, compared to that with a down-cut rotary tiller. Further investigation revealed that the rate of surface soil pulverization was higher in up-cut rotary tiller ridges than down-cut ridges, leading to the observed increase in soil temperature. Furthermore, this increased temperature related to increased lettuce yield associated with use of an up-cut rotary tiller.

View full abstract

The development of high quality seedlings contributes to the viability of sugarcane production. The purpose of this study was to examine the effect of electrolyzed water treatment on germination and initial growth of sugarcane seedlings. Electrolyzed water treatment is a safe method with low environmental impact; however, it has never been applied to the preparation of sugarcane seedlings. In this experiment, we prepared sugarcane seedlings with strongly acidic electrolyzed water (pH 2.3-2.4) or strongly alkaline electrolyzed water (pH 11.6-11.8) and allowed them to soak for 3-24 h. Electrolyzed water treatment had no effect on germination or growth of seedlings. However, the weight of roots was increased after 3 h of acidic electrolyzed water treatment. We conclude that acidic electrolyzed water treatment increased root growth and may therefore be useful in sugarcane cultivation.

View full abstract