Pecan

Pecan is the crop in this database with the best paper trail, and the reason is institutional. The USDA Agricultural Research Service has run a pecan breeding programme since 1930, and it curates the National Collection of Genetic Resources for Pecans and Hickories at Somerville, Texas, as part of the National Plant Germplasm System — collecting, documenting, preserving and distributing the material. Roughly thirty cultivars have been released from that programme. Where most of the species in this file rest on a nursery’s word, pecan rests on a public register.

Two biological facts shape every planting.

It cannot pollinate itself. Pecan is monoecious but dichogamous: the male and female flowers on one tree are not ready at the same time. Type I cultivars are protandrous — pollen sheds before the tree’s own female flowers are receptive. Type II are protogynous — the female flowers are receptive first. A block needs both, and every record below states the type, because it is the single most consequential line on the page. It is the same problem hazelnut solves with S-alleles and pawpaw solves with two clones, arrived at by a different route.

One fungus sorts the list. Pecan scab, Venturia effusa, is the dominant disease wherever summers are humid, and it is why a cultivar bred for west Texas can be worthless in Georgia. Read every resistance claim as local: scab populations vary regionally and a cultivar’s rating is a statement about where it was tested.

The third thing worth knowing is that the crop has a north. Pecan is native as far up as Illinois and Iowa, and a set of northern cultivars — most of them chance seedlings found in Kentucky, Indiana and Illinois between about 1900 and 1915, plus their bred descendants — ripen early enough to fill kernels in a short season. ‘Major’ is the taproot of that group: it is a parent of ‘Kanza’, ‘Lakota’ and ‘Hark’.

Rights split cleanly along institutional lines. The old chance seedlings pre-date the US Plant Patent Act of 1930 and are freely propagated. USDA-ARS releases have gone out as public varieties. The University of Georgia programme, working on scab resistance for the southeast, patents its releases and licenses named nurseries to sell them. Three eras, three answers.