Friday, January 22, 2016

Yield data from 2015 cultivar trials

    Harvesting pecans from cultivar trials takes a lot of effort. We harvest dozens of plots separately by cultivar, then work to clean and weigh the nuts from each plot. The results, however, are worth the effort. By the end of the harvest season, we have not only harvested thousands of pounds of pecans but we have also collected the data that allows direct yield comparisons between cultivars. In this post, I present the yields from 3 different cultivar blocks

    Our oldest cultivar trail was established in 1981 by planting one-year-old pecan seedlings. Trees were set on a triangular spacing with 35 feet between trees.These trees were grafted starting in 1984. During the winter  of 2008 (after the 2007 ice storm), we thinned the grove by removing every other row. Today these trees stand at a 35 by 60 foot spacing.
    The 2015 yield data for the nine cultivars in this trial is presented in the table at left. The yield per acre values were calculated from the per tree data based the current tree spacing. By far, scab-resistant Major produced the largest crop among these 9 cultivars. Yields from Colby, Dooley, Giles, Hirschi, and Peruque were terrible. The heavy scab pressure we experience in 2015 negatively impacted nut production from these 5 cultivars.
     In 1983 we transplanted more seedling trees to establish additional cultivar evaluations. These trees were planted on a 30 ft. by 30 ft. spacing then thinned in 2008 to the current spacing of 42 ft. by 42 ft. In 2015, Osage produced the greatest crop among these 9 cultivars (table at right). This was the "on" year for Osage, a severely alternate bearing cultivar. This past summer we thinned the nut crop on our Lakota trees and still produced an excellent crop. Yields from Giles and Chetopa trees were disappointing, producing less than 1/3 the crop as compared to other cultivars in this trial.  

   The table at left presents the yield data from a trial first established in 1991. This planting was established at a 30 ft. by 30 ft. spacing and is scheduled for thinning this winter. This was the first year Oconee produced a big crop for us. Oconee often ripens late in our area and this was the first time we harvested nuts with fully developed kernels. Caddo, Oswego, and Shepherd were other high yielding cultivars this year.
    In reviewing the results of all our cultivar trials make sure to remember that one year's data should not be used to plan a new massive grafting campaign. I've seen some of these cultivars long enough to know to avoid them (ie. alternate bearing Osage and USDA 64-6-182), while others still make me worry about their late ripening dates (Caddo, Oconee).