- Author: Therese Kapaun
- Editor: Elizabeth E Grafton-Cardwell
Claire Federici (UC Riverside, Dept. of Botany and Plant Sciences) examines Olinda Valencia oranges, hoping to locate seedless fruit. This group of Valencia trees are part of a long-running plant breeding project at Lindcove that is headed by Dr. Mikeal Roose, and is the same project that has brought low-seeded mandarins to global markets. The Valencia trees were grown from irradiated budwood, which has the intended result of occasionally disrupting the genes that promote seed formation. If a tree is found to have low-seeded fruit, then its budwood is likely to produce low-seeded fruit, and a new low-seeded line of Olinda is created!
While several varieties of seedless or low-seeded Valencias are commercially available, notably Delta and Midknight, the popular seedy Olinda variety is favored by San Joaquin Valley growers for high productivity and tolerance of hot summers.
- Author: Therese Kapaun
The mandarin trees in this one-year-old rootstock trial at Lindcove are getting their annual health evaluations, conducted by Dr. Mikeal Roose and Dr. Tracy Kahn (UC Riverside, Dept. of Botany and Plant Sciences). The varieties in this block include satsuma, clementine, and newly released low-seeded mandarin selections. The trial at Lindcove is replicated in different climate zones in several other locations in California. The project goals are to determine how well the varieties perform on three different trifoliate rootstocks, Carrizo, C-35, and Rich 16-6, as well as their performance in the different climates.
- Author: Therese Kapaun
- Editor: Elizabeth E Grafton-Cardwell
During the spring of 2013, all 12,000+ trees at the Lindcove Research and Extension Center were tested for citrus tristeza virus (CTV). This week, LREC staff treated and removed 36 CTV-infected trees. The CTV strains found at LREC have been mild, causing few if any symptoms in the trees. However, infected tree removal ensures the research plots are free of disease that could potentially affect the conclusions of the research.
- Author: Therese Kapaun
- Author: Elizabeth Fichtner
Lindcove REC has a small block of mature Manzanilla and Sevillano olive trees. In past years the trees have been used for olive fruit fly research and mechanical harvester field trials, but now are currently being used by Dr. Carol Lovatt, Professor of Botany and Plant Sciences at UC Riverside, and Dr. Elizabeth Fichtner, UCCE Farm Advisor in Tulare County. Their research is investigating the physiological mechanism underlying alternate bearing in olive with the goal of utilizing plant growth regulator treatments for mitigation of alternate bearing.
The alternate bearing cycle in table olive results in a heavy crop one year followed by a light crop the next year. Alternate bearing is disadvantageous to growers and processors because it affects the total annual yield of the crop and the average fruit size. The first goal of the project is to better understand the nature and timing of fruit’s inhibition of vegetative shoot growth and return bloom in olive. To achieve this goal, the research team collects olive shoots throughout the season and excises buds in the laboratory for analysis of expression of floral genes, natural plant growth regulator production, and visualization of floral and vegetative bud development. Understanding the timing of floral bud development in olive will allow growers to effectively time plant growth regulator treatments on mature trees to counteract or eliminate the alternate bearing cycle.
- Author: Therese Kapaun
- Editor: Elizabeth E Grafton-Cardwell
Field trials evaluating the systemic uptake of neonicotinoid insecticides into citrus trees are in their third year of evaluation at Lindcove REC. Dr. Frank Byrne (right) and Richard Aubert (left) from the Department of Entomology (UC Riverside) are mixing up a batch of Belay insecticide to be applied to mature Parent navel orange trees. One strategy is to apply the insecticide under the tree as a soil drench and another strategy is to apply it as a trunk spray. Belay, which is not yet registered for citrus, is in the neonicotinoid class of insecticides, which are recommended insecticides for control of Asian citrus psyllid. Dr. Byrne is comparing the two methods of application to see how they affect the rate of uptake of the chemical and what level of protection from the Asian citrus psyllid is imparted to the tree.