Submitted to: Journal of American Pomological Society
Publication Type: Peer reviewed journal
Publication Acceptance Date: 5/19/2004
Publication Date: 10/22/2004
Citation: Malik, N.S., Bradford, J.M. 2004. Genetic diversity and clonel variation among olive varieties offer promise for selecting cultivars for Texas. Fruit Varieties Journal. 58:203-209. Interpretive Summary: Researchers at Texas A&M University discouraged cultivating olives in Texas based on their theoretical interpretation of climatic data from olive-growing countries; they never conducted any actual experiments. Growers, however, are strongly interested in cultivating olives in Texas because olive treees are tolerant to low water and fertilizer inputs and there is still a vast land available for cultivation in the Texas Valley. USDA has decided to help growers investigate the possibilities of growing olives in Texas on a commercial scale. As a start, a survey was conducted on various olive groves within Texas to study if any varieties or any trees within a variety grown during the last 5-6 years have shown adaptation to local climates. The primary phenotypes of interest selected for the survey were the ability of trees to flower under mild winters of the Texas Valley. Our survey identified two trees that showed extraordinary adaptability to mild winter temperatures. One of the trees produced flowers even in the Weslaco area that the earlier researcher designated as an area where olives can only grow vegetatively. This remarkable adaptability was detected in trees from among a very limted population of trees, and therefore, offers a great hope for possible development of olive cultivars suitable to Texas conditions. Clones from these trees are now being produced and will be tested at various locations during the next few years. In addition, more trees from climates similar to Texas will be imported and evaluated in the coming years.
Technical Abstract: Some researchers in the past have discouraged the cultivation of olives as a commercial crop in Texas. Their agrument was primarily based on the temperature data of olive-growing areas in the world versus the climatic conditions in Texas. Actual growth and performance of olive trees were not tested at any location in Texas. However, approximately 5-6 years ago, interested farmers started a few olive groves on a trial basis at different locations in the Texas Valley. Normally, olive trees mature and then start flowering and fruiting within 4-6 years; early maturing varieties can produce fruits within a year. A survey on the performance of these trees was, therefore, conducted during the 2002 and 2003 seasons to ascertain whether adaptability to local climatic conditions exists among clones of various olive varieties planted at different locations. The survey identified two trees with striking adaptability to local climatic conditions, thus producing flowers and fruits under conditions in which other olive trees did not flower. In addition, several trees were identified that produced remarkably well at different locations under climatic conditions that were marginally conducive to flowering. This information about the adaptability of some trees to the Valley climate offers hope that promising cultivars of olives could be developed for Texas by tapping into natural genetic diversity, clonal variation, and the ability of olive plant accessions. Additionally, there is a need to further evaluate the performance of selected trees and to import more varieties from areas of climatic conditions similar to Texas for additional testing at different sites in Texas.