Research Library

Employing a molecular marker-guided methodology can accelerate the breeding of Avocado. One advantage of the molecular approach is that it eliminates the step of growing seedlings to mature trees: instead, seedlings are screened for the presence of markers correlated with desirable traits.

The project was scaled back from the original proposed objectives due to a reduction in funding from the requested amount. In light of this the research emphasis for this year was made following consultation with G. Witney. The aim of this the project for the current funding year is to study the influence of fruit maturity and handling following fruit harvest on the concentration of various phytonutrients of ‘Hass’ avocado.

This project will help to maintain and enhance the California avocado industry by continuing our research efforts to examine the impact of temperature and ethylene on the ripening quality of ‘Hass’ avocado and the susceptibility of avocados to mechanical injury following harvest. The final objective is to continue our adaptation of 2 postharvest manuals developed in New Zealand for the California industry for use in standardization of terminology and measurement of fruit quality at the packinghouse, wholesale and retail levels.

This project is aimed at evaluation and recommendation of rootstocks that are useful for production of avocado on saline soils. Rootstocks identified as salinity tolerant and that also meet criteria with respect to productivity and Phytophthora resistance from other related projects will be recommended for commercial release. Rootstocks with high salinity tolerance are also being incorporated into the breeding program.

This project will provide avocado growers with information on which rootstocks are most useful for production of avocado on saline soils. Identification of rootstocks that can be incorporated into the breeding program will eventually allow growers to use irrigation water having a higher salinity content that is currently used for avocado production. As water costs increase and growers rely increasingly on saline water for irrigation, this will permit use of higher salinity water with lesser damage to the trees and concomitant reductions in crop yield.

This research project will be ending October 31, 2008 and we are on schedule to accomplish all of the major goals laid out for the project. Although the avocado lace bug (ALB) has not spread into commercial avocado orchards in California, we could not have predicted ahead of time that this would not happen and it is possible a more virulent strain might be introduced into California at some point in the future. In some areas of the world, ALB is a very serious pest on avocados.

To manage foliage and fruit damaging thrips it is imperative to determine how widespread and abundant N. burungae is in comparison to S. perseae. Field surveys undertaken to delineate the range inhabited by N. burungae, its abundance in comparison to S. perseae, and its seasonal phenology will greatly aid understanding when assessing the potential pestiferousness of this new invader.

In December 2004, Neohydatothrips burungae was collected from avocado trees in San Diego California during a survey for avocado lace bug. Neohydatohrips burungae has been collected from avocados in Mexico and Guatemala by Hoddle (Hoddle et al., 2002). In Mexico, this thrips was as common as avocado thrips, Scirothrips perseae, in areas of intermediate altitude. In colder high altitude areas S. perseae dominated, almost exclusively, and in warmer more humid lowland areas N. burangae was dominant on avocados.

In December 2004, Neohydatothrips burungae was collected from avocado trees in San Diego California during a survey for avocado lace bug, Pseudacysta perseae (Hemiptera: Tingidae). Neohydatothrips burungae has been collected from avocados in Mexico and Guatemala by Hoddle (Hoddle et al., 2002). In Mexico and Guatemala this thrips was as common as avocado thrips, Scirtothrips perseae, in areas of intermediate altitude. In colder high altitude areas S. perseae dominated, almost exclusively, and in warmer more humid lowland areas N. burungae was dominant on avocados.

In December 2004, Neohydatothrips burungae was collected from avocado trees in San Diego California during a survey for avocado lace bug. Neohydatohrips burungae has been collected from avocados in Mexico and Guatemala by Hoddle (Hoddle et al., 2002). In Mexico and Guatemala this thrips was as common as avocado thrips, Scirtothrips perseae, in areas of intermediate altitude. In colder high altitude areas S. perseae dominated, almost exclusively, and in warmer more humid lowland areas N. burungae was dominant on avocados.