Agriculture Reference
In-Depth Information
Table 7.3. Classi fi cation of selected avocado cultivars according to fl ower types and
climate adaptation.
Type A
Type B
Subtropical
Anaheim,Wurtz
Bacon, Edranol
Hass, Lamb Hass
Fuerte, Ettinger
Gwen, Hazzard
Nabal, Millicent
Jalna, Pinkerton
Ryan, Sharwil
Reed, Rincon
Zutano,Colin V-33
Tropical
Catalina, Collinson
Booth 7, Booth 8
Choquette, Fairchild
Gripiña No. 2, Hall
Lula, Princesa
Itzamna, Kampong
Russell, Semil 34
Linda, Monroe
Semil 42, Semil 44
Pollock, Prince
Simmonds, Waldin
Semil 43, Winslowson
Flowering occurs from late autumn to spring, depending upon the cultivar
and prevailing temperatures (Fig. 7.3). West Indian and Mexican cultivars
generally may start to fl ower early, in October or November and October-
December, respectively, north of the equator. The West Indian avocado is
called the summer avocado in Hawaii. Guatemalan cultivars and many
Guatemalan × Mexican hybrids begin to fl ower around March, extending to
May, and are called winter avocado in Hawaii. In the largest 'Hass'-growing
area in the world, Michoacán, México, the trees can fl ower three or four times
per year; the fi rst, called 'crazy' fl owering, occurs in August-September, the
second or 'advanced' in October-November; the 'normal', which generally is
the heaviest, occurs in December-January and, fi nally, the 'March' fl owering,
which takes place at the beginning of spring. These fl owering events may not
occur in all trees, and the intensity of fl owering will vary according to the fruit
set in the other fl owering cycles (Salazar-García, 2000).
Pollination and fruit set
The protogynous, diurnally synchronous dichogamy in avocado fl owers is
the normal behaviour and occurs if warm weather prevails during fl owering.
Synchronous dichogamy of fl owers of the same cultivar restricts self-
pollination and encourages cross-pollination between those of complementary
groups. Exposure to sun, wind and temperature changes can cause variability
in the time of fl oral anthesis, prolonging the open period and time between the
two open periods, and increasing the overlap of female and male opening on a
single tree. However, with moderate day temperatures (25°C) and cool nights
 
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