Blog 4 - Improving Plants
Blog 4 - Improving Plants
Is the pecan self-pollinating or cross-pollinating?
The pecan tree has both female and male organs, but they are not located together, which is called monecious flowering.
Logically,
if a crop has only one reproductive organ it is not able to self-pollinate. And
if it does, looking at the time-span of the receptiveness of each organ helps
identifying its ability to self-pollinate or not. Mostly, plants that are able
to self-pollinate are also able to cross-pollinate. Another insight is the
amount of pollen grains. Self-pollinating crops do not require large amounts
for they are simply located near to the pistil. Cross-pollinating crops have
larger amounts of pollen grains, for they have to be carried by the wind, water
or animals first in order to reach the pistil.
Figure 1 Pecan nuts, different cultivars (Grauke & Thompson, n.d.) .
Breeding program for the American Pecan
Several breeding programs have taken place in the
United States and more are expected to follow. Looking at one in particular we
will go into details why the breeding program was necessary and what the
characteristics are of the cultivar that has been created.
The University of Georgia started a breeding program
of pecan trees in 1998. The University has started up new pecan breeding
programs since then. The newest published evaluation on the breeding and
cultivar program is one that was conducted from July 2010 till June 2015. (University of Georgia, 2015) . The humid
conditions of the Southern States of the United States, where the pecan
production is located, are the source of growing fungi. These fungi are the
source of scab infections. The main dilemma in breeding is to find a cultivar that is both fungi
resistant and has the desirable nut quality traits. (See Figure 1). Commercial pecan plantings require 8-11
applications of fungicides in order to remain profitable. Profitability of a
commercial plantation is also an issue that is addressed by breeding new
cultivars also plays an important role in the innovation of pecan growing. (University of Georgia, 2015) .
The breeding program that was conducted by the
University of Georgia was done in a traditional way. The pollination was done
in a controlled matter. The nuts were harvested, stratified for six weeks and
then planted again. The cultivars were selected on tree productivity, nut
quality, phenology and insect and disease resistance. (University of Georgia, 2015) .
The results of the plant breeding program
The new
cultivars have a good scab pressure which could result in as much as 80% of
their offspring (progenies) being discarded for scab susceptibility. With their
sufficient nut quality traits as well as fungi resistance using these cultivars
could result in production cost savings. While over the years pecan nut prices
have only increased with 4% in the period 1980-2015 the production costs of the
nuts have risen over 154% in that same period. The savings could be
approximately up to $115 per acre per year. The reduction of the costs will be
on fungicide usage and labour. (University of Georgia, 2015) . With the stress on
low production costs in the pecan industry the need of innovations on this
field are very much needed.
If you plant a crop of the same genotype in different regions in your country, will the phenotype be the same?
To be able
to understand the sub issue we will look at the definition of both genotype and
phenotype.
Genotype
The
genetic constitution of an individual organism. (Oxford
Dictonaries, n.d.) .
Phenotype
The
observable characteristics of an individual resulting from the interaction of
its genotype with the environment. (Oxford
Dictionaries, n.d.) .
So the
phenotype = genotype + environmental conditions. So, basically how the plant
ends up developing. While a plant may share its genetical identity with
another, the environmental conditions will eventually determine how the plant
grows and develops. To give examples, its supply of sunshine, water and its
rivalry with other plants. There are many more parameters that will determine
how fast the plant will grow. Not only the genotype will influence nut quality
and production capacity, but also the environmental conditions of each
individual tree.
References
Byford, R. (2005,
May). Growth and Development of Pecan Nuts. Retrieved from New Mexico
State University: http://aces.nmsu.edu/pubs/_h/H618.pdf
Colorado State
University. (2004, March). What Are Transgenic Plants? Retrieved from
Colorado State University:
http://www.cls.casa.colostate.edu/TransgenicCrops/what.html
Diffen. (n.d.). Cross
Pollination vs. Self Pollination. Retrieved from Diffen:
http://www.diffen.com/difference/Cross_Pollination_vs_Self_Pollination
Grauke, L., &
Thompson, T. (n.d.). Pecan cultivars. Retrieved from Agricultural
Research Service, U.S. Dept. of Agriculture:
http://cgru.usda.gov/carya/pecans/03/yba1912.jpg
Oxford
Dictionaries. (n.d.). Phenotype. Retrieved from Oxford Dictionaries:
https://en.oxforddictionaries.com/definition/phenotype
Oxford
Dictonaries. (n.d.). Genotype. Retrieved from Oxford Dictonaries:
https://en.oxforddictionaries.com/definition/genotype
Smith, M. (n.d.).
Botany. Retrieved from Oklahoma State University: http://pecan.okstate.edu/html/introduction/id.htm
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