Desperately Seeking Seedless

Citrus Nursery Source: Desperately Seeking Seedless

In spite of citrus greening and canker being the focus of most current citrus research in Florida, work to develop resistance to these two diseases has been possible only for a few years due to regulatory issues. On the other hand, efforts to produce seedless scion varieties have been ongoing for decades, and products of those efforts have just become available. Over the years, a number of important citrus scion varieties including Minneola (1930), Sunburst (1979), and Fallglo (1987) have been developed and released from the USDA citrus breeding program in Florida. These varieties have had significant impact on fresh fruit trade in Florida as well as other citrus producing regions. However, a common fault shared by each of these important varieties is that they are seedy; whereas in the current market place, seedless citrus fruit is highly desired and can command higher prices than does seedy fruit.

Two new seedless citrus scion varieties, US Seedless Pineapple and US Early Pride, generated by our program were officially released in 2009. Irradiation of seeds was used to induce the seedless character in Pineapple sweet orange (an important midseason processing orange) resulting in US Seedless Pineapple.

Irradiation of budwood was used to induce the seedless character in Fallglo (an important early season mandarin in Florida) resulting in US Early Pride. Results of extensive testing indicate Seedless Pineapple and Early Pride are essentially identical to their seedy progenitors except for the absence of seeds. Seedlessness is a desirable trait in citrus fruit and having seedless variants of otherwise high-quality, established cultivars is of value to the citrus industry.

Seedless Pineapple budwood is available to the public from the Florida Department of Agriculture and Consumer Services Division of Plant Industry Budwood program Chiefland. Early Pride is being considered for patent protection based on requests from the Florida, California, Arizona, and Texas citrus industries. US Early Pride trees are available through an agreement between the USDA-ARS and the New Varieties Development & Management Corp.

It’s In The Genes

The utility of producing seedless variants of standard citrus scion varieties, as demonstrated with Seedless Pineapple and Early Pride, has caused us to devote considerable effort to irradiation of standard seedy scion varieties as well as seedy, but otherwise promising new hybrids in our breeding program. We currently have about 2,000 grafted trees produced from irradiated budwood of several selections in the field in an effort to identify seedless variants. Fruit produced from the irradiated material is evaluated for the presence of seeds. When low-seeded or seedless variants are identified, they are propagated for further evaluation, a process that requires several years.

Handle On Hybrids

Another approach used in our effort to generate new, valuable citrus varieties is to produce hybrids using standard but seedy cultivars as the female (fruit producing) parent in combination with Seedless Kishu, a citrus variety that is naturally seedless, as the male (pollen) parent. Our hypothesis is by using Seedless Kishu as the pollen parent, we should be able to generate at least some hybrids that produce seedless fruit. We are eagerly awaiting production of fruit by these hybrids so we may determine if any of them are seedless. As with all citrus hybrids, these seedling trees must overcome juvenility before they begin to flower and produce fruit, a process that can take numerous years. In an effort to reduce the length of the juvenile phase and thereby shorten the time to fruit production, we have been growing our seedless Kishu hybrids in the greenhouse and pruning them to a single stem, a technique that has been reported to reduce the length of the juvenile phase.

Continued Development

Regardless of techniques used, development of new citrus varieties is an inherently lengthy process, typically requiring decades from creation of new germplasm, thorough evaluation, and eventual release. Objectives that seem important today may be insignificant in five, 10, or 50 years. The need to develop citrus varieties with resistance to citrus canker and citrus greening were not apparent until just recently, and in fact, efforts to produce new varieties resistant to these diseases were not previously possible. Developing varieties with resistance to canker and greening by utilizing the most advanced technologies available has become the focus of our most recent efforts and already progress has been made. It is virtually certain sustainable solutions to these two diseases will become available. When they do, there will still be the need for seedless, high-quality scion varieties to ensure the U.S. citrus industry maintains a competitive advantage. The USDA citrus improvement program is well positioned to continue to contribute such varieties.

Leave a Reply

Featured Stories
Biofungicides supplement methyl bromide alternatives
Berries
February 5, 2016
Moving Beyond Methyl Bromide With Biofungicides
Editor’s note: University of California Farm Advisor Mark Bolda will present much more information on this topic at the Biocontrols Read More
Geotextiles being installed.

Photo: Jim Willwerth
Grapes
February 5, 2016
Geotextiles Can Help Prevent Winter Grapevine Damage
Although Northeast and Midwest grape growing regions have so far been spared from extreme cold this year, the winters of Read More
The canopy of the vines that received the under-canopy sprinkler irrigation just on hot nights during heatwaves appear to be healthier than the control vines and have a higher yield.
Photo: Michael McCarthy
Grapes
February 5, 2016
Researchers Test New Method To Mitigate Vine Heat Stress
The use of evaporative cooling in vineyards during hot weather isn’t a new concept, but researchers in Australia are testing Read More
Biocontrols USA 2016 logo
Crop Protection
February 5, 2016
Register Now For Biocontrols Conference 2016 Field And Greenhouse Tour
Space is limited, so register now to attend the first-ever Biocontrols USA 2016 Conference Field and Greenhouse Tour. Following the Read More
La Crescent produces a good quality white wine with apricot-like flavor. The off-dry, sweet white wine pairs well with appetizers, seafood and chicken. La Crescent has excellent winter hardiness with moderate disease resistance that requires a standard spray program.
Grapes
February 4, 2016
Northern Grapes Project Fuels A Market For Cold-Hardy Grapes
 There’s a burgeoning market for cold-weather grapes. The Northern Grapes Project, funded in 2011 by a USDA National Institute of Read More
two glass goblets of olive oil
Citrus
February 4, 2016
Can Olive Oil Grease Skids For Florida’s Slipping Citrus Trade?
Researchers, interested growers help launch new industry. Read More
Sunkist organic lemons being harvested at the Donlon Ranch in Ventura County, CA by Jane and Ned Donlon, 5th and 6th generation growers, respectively.
Citrus
February 3, 2016
Sunkist Expands Organic Portfolio
With the organic citrus sector growing three times as fast as conventional, the 123-year-old cooperative is keeping up with the times. Read More
money
Citrus
February 3, 2016
Syngenta OKs Buyout By ChemChina
Deal valued at more than $43 billion; Syngenta management team to stay intact. Read More
UFGem peach variety
Farm Marketing
February 3, 2016
Florida Peach Marketing Order Fails
Growers don’t meet 65% approval needed for passage. Read More
Western Growers'  Center for Innovation & Technology is a technology incubator designed to bring innovative entrepreneurs together with growers to facilitate creative solutions to the biggest challenges facing agriculture.
Farm Management
February 3, 2016
Western Growers Launches Tech Talk Series
Speakers from a variety of agricultural technology areas will make presentations on a variety of topics including drone/satellite imagery and food safety software. Read More
The Latest
Berries
February 5, 2016
Moving Beyond Methyl Bromide With Biofun…
Editor’s note: University of California Farm Advisor Mark Bolda will present much more information on this topic at the Biocontrols Read More
Grapes
February 5, 2016
Geotextiles Can Help Prevent Winter Grap…
Although Northeast and Midwest grape growing regions have so far been spared from extreme cold this year, the winters of Read More
Grapes
February 5, 2016
Researchers Test New Method To Mitigate …
The use of evaporative cooling in vineyards during hot weather isn’t a new concept, but researchers in Australia are testing Read More
Crop Protection
February 5, 2016
Register Now For Biocontrols Conference …
Space is limited, so register now to attend the first-ever Biocontrols USA 2016 Conference Field and Greenhouse Tour. Following the Read More
Grapes
February 4, 2016
Northern Grapes Project Fuels A Market F…
 There’s a burgeoning market for cold-weather grapes. The Northern Grapes Project, funded in 2011 by a USDA National Institute of Read More
Citrus
February 4, 2016
Can Olive Oil Grease Skids For Florida’s…
Researchers, interested growers help launch new industry. Read More
Citrus
February 3, 2016
Sunkist Expands Organic Portfolio
With the organic citrus sector growing three times as fast as conventional, the 123-year-old cooperative is keeping up with the times. Read More
Citrus
February 3, 2016
Syngenta OKs Buyout By ChemChina
Deal valued at more than $43 billion; Syngenta management team to stay intact. Read More
Farm Marketing
February 3, 2016
Florida Peach Marketing Order Fails
Growers don’t meet 65% approval needed for passage. Read More
Farm Management
February 3, 2016
Western Growers Launches Tech Talk Serie…
Speakers from a variety of agricultural technology areas will make presentations on a variety of topics including drone/satellite imagery and food safety software. Read More
Farm Management
February 3, 2016
Hot Topics Tackled At Mid-Atlantic Fruit…
Food safety and GMOs were two of the topics discussed on the first day of the trade show and conference. Read More
Citrus
February 3, 2016
Historic Rainfall Hampering South Florid…
El Niño express delivering floods, uncertainty for crops. Read More
Nuts
February 3, 2016
Avoid Tree Nut Cargo Theft
American Fruit Grower® and Western Fruit Grower® recently reported on a rash of nut thefts, in which truckloads of nuts Read More
Nuts
February 3, 2016
Tips To Help Secure A Good Beekeeper Agr…
Pollination is one of the most important aspects of almond growing, and this time of year, making sure you have Read More
Apples & Pears
February 2, 2016
Fine Americas Introduces Next Generation…
New formulation of Exilis 9.5 SC is five times more concentrated than previous product; it's also easier to pour, handle. Read More
Fruits
February 2, 2016
EPA Releases List Of Products Labeled Fo…
Agency gives recommendations on products to protect hives against parasites. Read More
Fruits
February 2, 2016
California Fresh Fruit Association Names…
Issues such as water, labor, and food safety top the 2016 priorities. Read More
Vegetables
February 2, 2016
Rethinking Water In The West
While El Niño could significantly help with the drought in the West, when we look toward the future, we cannot rely on El Niño events to solve the water crisis in the West Read More
[gravityform id="62" title="false" description="false"]