Ag at Large: Citrus future may be shrunken trees

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Orange growers and others in the citrus industry, especially researchers, are exploring the possibility of reducing the size of trees that produce their crops. A few have done so already.

They can envision harvesting entire orchards without ladders; pickers reaching all the fruit while standing on the ground. Spraying nutritional or crop protection materials can be done with less powerful and less expensive equipment when trees are only head high. Land suitable for growing trees can support two or three times as many as it does now.

Any grower accused of dreaming about such outcomes only has to point to the experience of apple growers in Washington who were so willingly overtaken by the move to dwarf trees 60 years ago. Rootstocks that confined the growth of trees budded to them by nearly 100 percent became the rage.

Consumers hardly noticed. They had no reason to; only that their beloved, crisp and colorful apple varieties were more plentiful than ever. Growers noticed in major ways, planting twice as many trees in given orchard land and reaping more profitable crops. The industry grew rapidly behind the burgeoning production.

The rootstocks that vitalized the northwest apple industry were developed at two research stations in Great Britain. Concentration of the current effort in California is centered at the University of California’s Citrus Research Center at the Riverside campus.

Primary research is being carried forward there by Dr. Georgios Vidalakis, supported by others in the university’s breeding program. An important key in the process is the Citrus Research and Extension Center at the Lindcove station in Tulare County.

Dr. Vidalakis reports that some minor dwarfing of citrus trees can be observed by the slow growing citrus rootstock “flying dragon.” Other dwarfing effects due to citrus viroids have been studied carefully through the years, with causes documented. In the 1980s, plant breeders in Florida developed a rootstock that caused significant dwarfing, deepening interest by plant scientists at the U.S. Department of Agriculture.

A major outgrowth of the phenomenon of dwarfing is the Citrus Clonal Protection Program directed by Dr. Vidalakis. It carefully documents research projects that lead to dwarfing and maintains contact with all elements of the citrus industry that might be involved or affected.

In the meantime, one orange grove in eastern Tulare County has produced crops equal to the industry average for many years, picked by workers who easily reach the treetops while standing on the ground. Its proud performance continues each year, whether researchers can define the cause for its dwarfing or not.

The potential increase in production and other adjustments that dwarfing offers cause all aspects of the citrus industry to pay close attention. Citrus nurseries are among those on the front line of any new materials or methods. Eventual increases in sales volumes attract the attention of economists and others who deal with sales at home and abroad.

Packinghouse operators and managers consider needs for expansion, along with equipment designers and manufacturers. Others wonder if dwarfing rootstocks can apply in the grapefruit, lemon and, especially, tangerine quadrants, where enormous volume increases have already occurred and attracted significant consumer excitement.

The Citrus Research Board in Visalia is directing funds to Dr. Vidalakis and others, making sure that all aspects of a potential industry-wide upheaval are charted, supported and maintained.

California’s widely respected citrus industry has handled and profited from persistent growth with enviable balance and foresight for more than a century. Its new challenge may be in dealing with smallness. That may require the aplomb of the forever admired Snow White.

Don Curlee :