XVI International Botanical Congess

High temperature (HT) induces pod abscission, which is the major cause of yield reduction. HT during reproductive stage prevents normal pollen development. The objective of this study was to clarify relationship between pollen fertility and pod set as affected by HT. Snap bean plants were grown on 1/5000 wagner pot in a glass house. During reproductive stage, various HT treatments were made on plants using growth chamber. After HT treatment, flowers whose pollen fertility was determined were monitored their pod set. HT one day and ten days before flowering decreased pod set ratio while pollen fertility was reduced only by HT 10 days before flowering. Highly positive correlation was observed between pollen fertility and pod set ratio of flowers that experienced HT 10 days before flowering. We conclude that decline in pollen fertility due to HT 10 days before flowering reduced pod set ratio. No significant cultivar difference was observed in this relationship.