Abstract
The effects of high (day/night=30/25°C; H) and low (23/17°C; L) air temperatures on the development of pistillate flowers (PFs) during the seedling stage were clarified in 7 cucumber cultivars (Cucumis sativus L.) in order to identify potential high-yield cultivars in summer. Most of the cultivars developed nodes at a higher rate with H treatment than with the L treatment; however, the number of PF nodes and the total number of PFs on a plant were decreased with the H treatment in ‘028’ (multi-pistillate monoecious cultivar), ‘NK×AN8’ (mono- or di-pistillate gynoecious cultivar) and ‘Toyooka’ (multi-pistillate gynoecious cultivar). With H treatment, ‘028’ and ‘NK×AN8’ bore one PF or less per node, while ‘Toyooka’ produced 1.7 PFs per node. When the ‘028’ and ‘NK×AN8’ cultivars were grown in spring and summer, the PF numbers per PF node during summer were lower in the ‘028’ cultivar but not in ‘NK×AN8’. The fruit abortion rate was higher in summer in both cultivars, and it was reduced slightly by pollination. This study suggests that gynoecious cultivars could achieve a high yield in summer within a short growing period because they bear more PFs per node than multi-pistillate cultivars, and the effect of pollination on fruit abortion was too small to realize a high yield in summer.
