This study was conducted at several periods of time from 2000 to 2005 in two commercial ‘Hass’ avocado orchards in the municipalities of Tepic and Xalisco, Nayarit, México. The objective was to determine the growth cycles of ‘Hass’ avocado trees under rainfed conditions. ‘Hass’ showed two flushes of vegetative growth: winter (greatest intensity) and summer (lowest intensity). The complete floral development process, from closed pointed bud to anthesis, required 11.5 and 7.5 months for winter and summer shoots, respectively. Greatest production of roots occurred in August. “June fruit drop” maximum intensity (45 %) was observed during the first summer rains (June). Fruit growth (length), from set (March) to harvest (November), took eight months. Average annual maximum air temperatures fluctuated between 26.8 and 33.4 °C and minimum temperatures were 9.3 to 20.4 °C. Average monthly maximum soil temperatures varied from 20.1 to 24.5 °C throughout the year and the minimum ranged from 18.5 to 23.4 °C. Soil moisture level was ³85 % from the rainy season (June to October) to December; afterwards it decreased, reaching 65 % in May.

....