Plant Management

2005 Robert R. Krueger (Seasonal Variations in N Uptake & Nutrient Concentrations in Mature Field-Grown Citrus)

Seasonal Variations in N Uptake and Nutrient Concentrations in Mature Field-Grown Citrus

Final Report
This constitutes the final report for this project. A few data points are missing due to delays in isotopic analysis, however estimates have been made for the missing points as referenced below. The objectives of this study were to measure seasonal variations in mineral nutrient concentration and mass in vegetative organs and fruit of mature citrus trees, to estimate seasonal variations in nitrogen uptake, and to estimate the amount of nitrogen removed from soil.

2005 Carol J. Lovatt (New Field Uses for Four Commercial PGRs)

New Field Uses for Four Commercial PGRs

The goal of this research is to determine the commercial value (cost/benefit) of four PGRs – CPPU, AVG, Prohexadione-Ca and 3,5,6TPA – to solve citrus production problems.

2005 J.E. Adaskaveg (Etiology & Management of Rind Breakdown of Mandarins)

Etiology and management of rind breakdown of mandarins

Recent reports of preharvest rind decay of mandarins included cases with severe crop losses in some citrus growing areas of California (Butte, Fresno, Tulare, and Kern Co.). The damage generally occurred shortly after rainfalls and was most severe on Satsuma mandarins. Symptoms were more frequently observed on fruit on the outer perimeter of the tree and on the exposed side of the fruit.

2005 Craig Kallsen ( Irrigation Stress & Early Navel Fruit Maturity)

Irrigation Stress and Early Navel Fruit Maturity

The objective of this experiment is to measure the effects of three levels of water stress initiated approximately August 1 on navel orange fruit size, yield, sugar/acid, color, and juice percentage. The results of this experiment should provide information for early maturing navels on the relationship between fruit quality parameters such as color, sweetness, juiciness, fruit size and yield.

2005 David A. Goldhamer (Using Regulated Deficit Irrigation )

Using Regulated Deficit Irrigation to Optimize Fruit Size in Late Harvest Navels

Grower profits with late harvest navels can be significantly reduced due to both excessively large fruit and granulation. We are evaluating regulated deficit irrigation (RDI) as a technique to produce optimal-sized high-quality fruit with late harvest (Lane Late) navels.

2005 Pat Unkefer ( Metabolomic Analysis of Citrus )

Metabolomic Analysis of Citrus

Metabolomics is the study of the entire metabolome within a system, allowing for a more comprehensive look at how that system functions and reacts. The overall objective of this project is to establish metabolomics as a useful tool to analyze the metabolic state of citrus (navel orange). This tool will be applied to characterize the effects of such agriculturally important factors as changes in field management practices such as nutrient regimes, growth regulator use, timing of harvest and postharvest efforts, etc.

2005 C. Thomas Chao (Production & Management Strategies for New Mandarins in California)

Production and Management Strategies for New Mandarins in California

The main project objectives in 2004-2005 were to study compatibility and seediness among mandarins. In 2004-2005 we generated more information about compatibility/seediness among mandarins especially the compatibility and seediness issues with the triploid mandarins (Shasta Gold, Tahoe Gold and Yosemite Gold). The results from the 2004 hand cross-pollination at the UC Lindcove Research and Extension Center (LREC) are shown in Table 2.

2005 C. Thomas Chao & Carol J. Lovat (Improving the Efficacy of GA3)

Improving the Efficacy of GA3 to Increase Fruit Set and Yield of Clementine Mandarins in California

The overall goals of this research are to identify the proper rate, proper timing, and best frequency of GA3 and/or 1% urea applications to increase fruit set and yield of Nules Clementine mandarin (Citrus reticulata Blanco). We also will determine if there is any negative effect on the current and following year’s yield due too high a concentration or too frequent applications of moderate rates of GA3. We will provide growers with updated recommendations and the necessary data to amend the label for use of GA3 on Clementinemandarins in California.

2005 C. Thomas Chao (Registration of 2,4-D for Fruit Size and Yield Increase of Mandarins and Mandarin Hybrids in California)

Registration of 2,4-D for Fruit Size and Yield Increase of Mandarins and Mandarin Hybrids in California

The overall goal of this project is to seek permanent registration of 2,4-D for fruit size increase of mandarins and mandarin hybrids in California. We like to provide a tool for citrus growers in California to increase fruit size of mandarins and mandarin hybrids and increase growers’ return. We also like to collect two alternate bearing cycles (4 years) of data for Afourer mandarin at two locations and Minneola tangelo at one location.

2005 Craig Kallsen (Petroleum Oils as Navel Orange and Tangelo Fruit Thinning Agents)

Petroleum Oils as Navel Orange and Tangelo Fruit Thinning Agents

Since the 2001-02 crop year, the major objective of this project has been to determine how a summer application of I 0 gallons of a 440-weight narrow-range petroleum oil in a 200-gallon per-acre spray solution affects the alternate bearing, fruit size and yield of Minneola tangelo. In this report, the year refers to the year that the crop was harvested (which was in the spring following the previous year’s late summer oil application).