|To view the Power Point presentation click on the
shortcut on the left. If you do not have Power Point on your computer
click on the link to the right to install the Power Point viewer on
your computer. Please note: The Power Point files are very large and
may take a long amount of time to download.
"Pecan" is a Native American word of Algonquin origin that
was used to describe nuts requiring a stone to crack. The history of pecans
can be traced back to the 16th century, originating in central and eastern
North America and the river valleys of Mexico. George Washington and Thomas
Jefferson planted pecan trees in the 1700s. Washington called them Mississippi
nuts. Pecan trees can be magnificent, usually ranging in height from 70
to 100 feet but sometimes growing to 150 feet or more. Native pecan trees
over 150 years old may have trunks well over 3 feet in diameter.
Pecan is a member of the genus Carya, i.e. the hickories. In depth taxonomic
information on pecan and other hickories can be found at http://extension-horticulture.tamu.edu/carya/species/index.htm.
An understanding of the pecan tree's anatomy and its flowering habit
is important to understanding how to provide for the tree. Pecan trees
are monoecious, i.e. they have male and female flowers on the same tree,
but at different locations. The male pecan flower, the catkin, provides
the pollen. The female flower, the pistil forms the nut. The pecan flower
cluster consists of many pistils, each capable of forming a fruit containing
a seed, i.e. nut. The number of pistils in a flower cluster is influenced
by the cultivar and growing conditions.
Pecan trees are dichogamus, i.e. the tree's pollen shedding and pistil
receptivity occur at different times. Therefore, pecan trees require pollination
by a different cultivar or a native tree. Even if a particular cultivar
sheds pollen at the same time that its pistils are receptive, research
has demonstrated that more fruit aborts and nuts are smaller if the flowers
are self pollinated rather than cross pollinated.
Pollen shedding in relation to pistillate flower receptivity of
a single cultivar is referred to as protandrous, meaning that the pollen
is shed before the pistil is receptive, or protogynous, when the pollen
is shed after pistil receptivity. Oklahoma Cooperative Extension Service
cultivar suggestions refer to these as early (protandrous) or late (protogynous)
pollen shedders. Literature from other sources may refer to protandrous
as type 1 and protogynous as type 2.
Click Next to continue.