ENVIRONMENTAL CONDITIONS AFFECTING POLLINATION OF AVOCADOS

Abstract

These observations on orchard trees indicate a strong correlation between temperature and flower opening. When the maximum temperature did not exceed about 70° and the minimum about 53°, Fuerte, a type B variety, either had no fully expanded stage I (female) flowers or they appeared so late in the day that pollination was unlikely. Likewise type A varieties may have stage I flowers in the morning during a warm period and in early afternoon to late afternoon, or not appear at all during a cold period. Throughout the latter part of the blooming season when other conditions, both internal and external, of the trees apparently are most favorable for fruit setting, climatic conditions at Riverside are such that stage I flowers are relatively infrequent. During the same period at Los Angeles stage I flowers appeared quite regularly.