At the meeting of the Crop Advisory Committee for Pecans and Hickories held on 24 Sept. 1984 in Albany, Ga., a question was raised concerning the legitimate scientific name of the pecan tree. Two names are currently in use: Carya illinoensis (Wang.) K. Koch (3, 6, 7, 10, 12, 19) and Carya illinoinensis (Wang.) K. Koch (1, 2, 11, 18, 21). Current usage is heavily in favor of the former epithet. When the 2 names were used as key words in the BIOSIS Previews computer search file for articles written between 1977 and the present, 199 were retrieved under C. illinoensis, whereas only 1 was found under C. illinoinensis. Since Hortus Third uses the latter epithet, articles on pecan submitted for publication in horticultural journals are occassionally returned to their authors for revision. The purpose of this paper is to trace the history of the nomenclature of the pecan as it relates to this dispute and in the process, demonstrate that the strict rules of scientific nomenclature and common sense can both be satisfied by the use of the epithet Carya illinoensis.
Seven open-pollinated pecan [Carya illinoinensis (Wangenh.) K. Koch] stocks were grown in a nursery in blocks. Bud growth of ungrafted seedlings was influenced by rootstock, with growth being more advanced on `Curtis', `Elliott', `Apache', and `Sioux' seedlings than on `Moore', `Riverside', and `Burkett'. Bud growth of grafted trees was influenced by scion, with growth of `Candy' being most advanced, while `Cape Fear' trees were more advanced than `Stuart'. Growth of `Candy' grafted trees was affected by rootstock, with growth being more advanced on `Elliott' and `Curtis' seedling rootstock as compared to `Apache', Sioux', `Riverside', and `Burkett' seedling rootstock. Tree damage caused by a May freeze was directly related to bud growth and was influenced by scion and rootstock.
Putative resistance to the yellow aphid complex (Monellia caryella (Fitch) and Monelliopsis pecanis Bissell) in the `Pawnee' pecan [Carya illinoinensis (Wangenh.) K. Koch] cultivar was first noted in greenhouse tests by rating cultivars for relative amounts of honeydew on adaxial leaf surfaces. This resistance was confirmed in two field tests monitored from mid-June to mid-Oct. `Pawnee' supported significantly lower aphid populations during every rating period when relatively large numbers of these insects were present. `Navaho' also showed resistance, with `Desirable' having intermediate resistance and `Stuart' being very susceptible. Insect populations were also monitored on the four quadrants of each tree, with this quadrant effect being significant in only one test. This test had the highest populations on the West and lowest populations on the East.
Thirteen cultivars of pecan [Carya illinoinensis (Wangenh.) K. Koch] were monitored for bud break, pollen shed and stigma receptivity for 4 years at LSU Pecan Station, Robson, LA. Cultivars were generally consistent in displaying clear patterns of protogyny or protandry, although patterns were uncertain for some cultivars in some years. Mean dates of cultivar phenology varied significantly by year. Years with warm winter and spring temperatures had earlier seasons of growth and flowering than years with cooler temperatures. The duration of pollen shed and stigma receptivity varied between years. Protogynous cultivars, as a group, had greater bloom overlap than protandrous cultivars, although overlap varied between years for both dichogamy classes. The sequence of cultivar flowering relative to other cultivars varied between years, resulting in variable amounts of bloom overlap between cultivars in different years.