Why are warm conditions (>17C) desired during flowering?

• A. They require more water
• B. They slow down flowering
• C. They reduce berry size
• D. They speed up flowering

Answer: (D)

Warm temperatures during flowering speed up the plant’s development. For grapevines, flowering involves pollen release, pollen germination, and stigma receptivity, and these processes work more quickly when temperatures are above about 17°C. This leads to faster, more reliable pollination and fruit set, so flowering progresses sooner. If temperatures are cooler, these steps proceed more slowly, delaying flowering and often reducing yield. While very high heat can eventually harm pollen viability, within the range just above 17°C the main effect is an accelerated flowering process.