Tifton updates its variety trial with new selections.
Patrick Conner
New variety and selection evaluation is an important part of the University of Georgia’s pecan breeding program. Variety evaluation at the Coastal Plain Experiment Station began in 1921 with the establishment of an orchard by O.J. Woodard and continued under my predecessor, Dr. Ray Worley. Over the years, many new varieties have been added, and the orchards expanded, so that currently over 100 varieties and selections are represented.
Typically, new selections are planted out in a replicated orchard and studied over many years before a recommendation is made to growers. We believe it is vital that a selection be evaluated for several years, both as a young tree and as a mature tree, before strong recommendations are made. The first step in our evaluation process is to sort out those varieties that have obvious flaws and would be unlikely to be profitable varieties in most orchards. The majority of the selections tested are eliminated in this step, and often they can be removed from consideration after just a few years of production. Most varieties that are eliminated in this step suffer from problems such as extreme scab susceptibility, severe alternate bearing, low percent kernel, small size, or very low productivity. The difficult step comes next when we must decide which of those varieties without obvious flaws are good enough that we feel confident in recommending them for widespread usage. This is often a process of give and take and probably every researcher or grower will come to slightly different conclusions on the merit of some of these varieties. For this reason, we usually can not make a blanket recommendation but rather have to present the strengths and weaknesses of the selections and allow the grower to pick those most likely to match the qualifications that they are looking for in their operation. Every grower has a unique situation, and varieties will accordingly vary in their suitability. We also try to keep in mind that our test results are dependent upon the conditions in our orchards and a variety may perform better or worse in a different location.
Our main variety tests are located on the Ponder farm a few miles west of Tifton, Georgia. A replicated variety test was initially planted at this location by Dr. Worley in 1979, and additional varieties were added until 1991. The orchard consists of 21 rows of 12 trees spaced at 40 feet between trees and rows. This orchard is cycled so that ¼ of the orchard is replanted and a new variety test is begun every five years. This sets the maximum length of time for each test at 20 years. Since the trees begin to seriously crowd each other by this time and need thinning, and after this amount of time we have a good idea of the value of most varieties, trees are replaced rather than thinned. Cycling this orchard allows us to continually test new selections so that we can update and add to our recommendations in a timely fashion.
Cultural practices are according to UGA guidelines and in general we try to approximate the level of care commonly seen in commercial orchards. This includes irrigation, nutrient management, and monitoring and treating insect outbreaks. We attempt to manage scab so that the check varieties have a mild incidence of the disease with low damage levels. Trees are rated for the presence of leaf and nut scab, sooty mold, and black aphid damage. The test varieties are then compared to the check varieties such as ‘Desirable’ and ‘Sumner’ for pest resistance levels. Tree productivity is measured by shaking each tree independently and measuring the amount of nuts which drop within a specified area under the tree. A random sub sample is taken from the nuts harvested from individual trees and quality is measured in terms of nut size, percent kernel, specific gravity, percent fuzz, and kernel color.
The initial plantings of this orchard included varieties from the southeastern and western regions, USDA releases, and USDA selections. Results from these plantings have factored in to our recommending the varieties ‘Pawnee’, ‘Forkert’, ‘Caddo’, ‘Oconee’, ‘Kanza’, ‘Sumner’, and ‘Sioux’ (we also recommend other varieties that are not in this test). We recently have begun to update this test with 10 new selections planted in 2002, and 11 planted in 2005. Selections planted in 2002 and 2005 consist of advanced selections from the USDA breeding program, low-input selections from Dr. Bill Goff in Auburn, and selections obtained from Georgia growers. In addition, 'Desirable', 'Stuart', ‘Sumner’, and ‘Pawnee’ have been included as check varieties. Future selections tested in this program will contain similar material as well as selections from our own breeding program. Preference is given to selections with high levels of disease resistance combined with commercial quality attributes in an attempt to meet the obvious need for varieties with a large nut size, good quality, and higher levels of scab resistance.
A separate low-input orchard was also planted in 2005. This new orchard is located at a separate location on the Ponder Farm. Selections in this test will receive normal irrigation, pruning, and fertility, but will not be sprayed with pesticides. The purpose of this test is to determine how well new scab-resistant selections can do under these conditions. Homeowners and small hobby orchardists are usually unable to spray their trees. This test will simulate these conditions and provide us with a measure of how well pest-resistant varieties hold up under high-pressure conditions. Selections tested will include those planted in the Ponder variety test plus some traditional resistant clones such as 'Elliot' and 'Gloria Grande'. Clones will be evaluated for leaf and nut scab, black aphid damage, sooty mold buildup, yield, and percent kernel. The purpose of this test is not so much to document production ability as to provide information on the general ability of selections to be able to produce a usable crop without sprays.
We have recently updated and expanded our website with much of this information. This site includes information on our current variety recommendations as well as photos, descriptions, and productivity records of all the varieties we have tested. We also have sections describing our breeding program and reprints of some of our publications. The website can be accessed at this address http://sacs.cpes.peachnet.edu/pecan/ or you can do a google search for “Georgia Pecan Breeding”. Let me know (pconner@uga.edu) of any broken links or information you would like to see included on this site, as we want to make this site as user-friendly as possible.
We would like to thank the Georgia Commodity Commission for Pecan for providing funds to support this project.
Varieties and selections planted in 2002 and 2005.
* The information presented below is from the original testing locations. Most of the trees planted in Tifton have not yet begun to fruit and so we don’t yet have data from our location.
USDA selections:
‘Nacono’ – A selection from the cross ‘Cheyenne’ x ‘Sioux’ that was released in 2000 by the USDA. Large sized nut with excellent quality.
49-17-322 – A selection from the cross ‘Barton’ x ‘Schley’. These same parents that produced the ‘Oconee’ pecan.
82-17-680 – An open pollinated seedling from ‘Wichita’. Has shown surprisingly high scab resistance in Auburn tests.
85-1-2 – From a cross between an unnamed selection and ‘Osage’. Large size (50 nuts/lb) and high percent kernel (60%) in early Texas testing. Harvest date a few days after ‘Pawnee’.
86-3-666; 86-3-32 – From a ‘Cheyenne’ x ‘Pawnee’ cross made in 1986. Both selections were large (48 and 43 nuts/lb) and had a high percent kernel (60%) in early testing in Texas. Harvest date should be after ‘Pawnee’ but before ‘Desirable’.
Auburn selections:
‘B32054-59’ – An apparent ‘Schley’ seedling from Dougherty Co., Ga. with high percentage kernel. The parent tree appears to have better black aphid resistance and heavier yield than ‘Schley’. Susceptible to scab, but not as much as ‘Schley’.
‘Carter’ – A selection from southern Miss. that produces a large nut with medium quality. Tree has good scab resistance.
‘Cherryle’ – Selection from Grand Bay, Ala. with a large-sized nut of high quality. Resembles ‘Forkert’.
‘Gafford’ – Seedling from Butler County, Ala. with a medium sized nut, high and consistent yields and excellent scab resistance.
‘Headquarters 2-4’ – Likely an ‘Elliot’ seedling; from Macon Co., Ala. Has shown high yields, good quality and good scab resistance, but produces a small nut.
‘Jenkins’ – Seedling selection from northern Miss. with moderate nut size (55 nuts/lb) and 53% kernel, good pest resistance.
‘McMillan’ – Seedling from Baldwin county Ala., consistent bearer of mid-size nuts (56 nuts/lb), good scab resistance.
‘Register’ – Seedling selection from Covington Co., Ala. Has shown good scab resistance and produces a large, long nut.
‘Syrup Mill’ – A seedling from Mobile, Co. Ala. Medium size (65 nuts/lb.) and good kernel color, but low percentage kernel, about 47%, because of thick shell. Has good scab resistance and remarkable tree vigor and foliage condition. May be useful as Type I pollenizer for low input plantings.
‘Zinner’ – Seedling from Baldwin County, Ala. Medium-sized nut with a very bright golden kernel.
Georgia selections:
‘Byrd’ – Selection from a cross between ‘Desirable’ and ‘Pawnee’. Nuts average 52-56 nuts/lb and 61% kernel in early testing. Harvest date in late September.
‘Excel’ – Selection from Blackshear, Ga.. Large nut, similar to ‘Desirable’ with bright golden kernel. So far has shown excellent scab resistance.
‘Leger-1’ – Selection from Crisp Co. Ga. Medium sized nut from a tree with good scab resistance a record of consistent bearing.
‘Newt’ – Selection from Wilcox Co. Ga., large nut size with good quality.
‘Watson’ – Selection from Glennville, Ga. Large nut similar in appearance to ‘Oconee’. Thin shell and bright kernel.