Pecan cultivars have three different origins:
- chance seedlings,
- selections from seedling orchards or seeds planted by homeowners, or
- breeding programs.
Read more about our step-by-step pecan breeding process:
In the period from 1890 to the 1930's, a large number of cultivars were selected from seedling orchards, propagated, and released. Most of these cultivars were of marginal value, but a few exceptional varieties were selected including 'Stuart', 'Schley', 'Alley', and 'Pabst' which were instrumental in the development of the Georgia pecan industry.
The ultimate goal of our breeding program is to develop pecan cultivars adapted for use in the humid southeastern U.S. Potential new cultivars will be selected on the basis of large nut size, good cracking and shelling characteristics, early nut maturity, light colored kernels, and a cluster size small enough to ensure adequate filling. Resistance or tolerance to major insect and disease pests, especially pecan scab, will also be major goals.
Pecan cultivars are much like people, each is genetically unique. When you cross two cultivars, you get a lot of variation in the seedlings. Like children, they will resemble their parents, but they will also be unique. Most seedlings will be worse than the worst parent, so you need to look at a large number of seedlings to find a truly good one.
Pecan is monoecious, which means that it has male and female flowers at different locations on the same tree. The female flowers are located at the tip of the current season's growth, and if pollinated, will form the nuts. The male flowers (catkins) are at the base of the current season's growth. Normally the female flowers are not receptive at the same time the catkins are releasing pollen (dichogamy), so it takes another tree to be the pollinator. This helps to increase the genetic variability of pecan. This also means that if you plant a pecan nut, the seedling tree will be different from the parent tree. Pecan is wind pollinated, and the pollen can travel a large distance. However, for maximum pollination and fruitfulness, pollinators should be relatively close.
In pecan breeding, we need to make sure the female flowers are only pollinated by the male parent we choose, so the female flowers must be enclosed in bags before they become receptive. We accomplish this by placing white paper bags over the female flowers when they are still small. Later, when the female flowers are receptive, we use a hypodermic needle to puff pollen into the bag.
We utilize a mechanical lift to get up into the mature trees and bag the flowers.
Seed from the controlled crosses is then planted into pots to grow for a year. During this time we inoculate with scab and remove many of the susceptible seedlings.
Leaf scab of a scab susceptible seedling. Pecan scab is a fungal disease that must be controlled in southeastern orchards or large crop losses can result.
New pecan trees being set out in the seedling orchard.
Seedling orchard the next summer.
Seedling orchard in year eight.
In 5-10 years most of the seedlings will have produced fruit. The best will be kept for further trial, the rest will be removed so we can reuse the orchard space. Qualities we look for include: scab resistance, large nut size, early harvest date, high percent kernel, good shelling characteristics, light kernel color, and good tree vigor.
Seedlings began fruiting in 2007 and by 2009, several hundred and been evaluated for nut quality. Those that look good will be kept and monitored for nut quality each year. Here is one of our favorites. A cross between 'Barton' and 'Gloria Grande', it produces a large, well-filled nut in the first week of October. So far, no scab on our unsprayed tree.
Seedlings that don't make the grade get ground down to make room for the next progenies.
Selections from the seedling orchard that might be good enough to be a new cultivar will be placed in a replicated cultivar trial like the Ponder Variety Test. Those that perform better than the check cultivars will be considered for release. They will also be used as parents in the next breeding cycle.