P. Revilla et Wf. Tracy, MORPHOLOGICAL CHARACTERIZATION AND CLASSIFICATION OF OPEN-POLLINATED SWEET CORN CULTIVARS, Journal of the American Society for Horticultural Science, 120(1), 1995, pp. 112-118
Sweet corn is one of the most important vegetable crops in the United
States, however the morphology and phylogeny of open-pollinated sweet
corn cultivars has not been studied. Fifty eight open-pollinated sweet
corn cultivars were characterized with thirty-four descriptors to pro
vide information for breeders interested in broadening the genetic bas
e of sweet corn. Principal component analysis and cluster analysis wer
e performed to classify sw eet corn cultivars based on morphology. Als
o, relationships among morphological variables in this set of cultivar
s were determined. The general ordination of cultivars followed an axi
s representing earliness, and plant, leaf, and tassel size, while ear
and kernel attributes were less variable. The morphological variabilit
y among all of the widely used sweet corn cultivars, except ''Country
Gentleman'', was not greater than the variability found among the ''Go
lden Bantam'' strains. Based on morphology, 52 of the cultivars could
be considered as one race, which we propose be called ''Northeastern S
weets''. These may be a subset of the race ''Northern Flint''. Five of
the remaining cultivars are from the north-central or southwestern Un
ited States and may represent races from those areas. The sixth cultiv
ar is ''Country Gentleman'', a commercially important sweet corn culti
var. Due to the importance of ''Country Gentleman'' and the introgress
ion of nonsweet germplasm into modern sweet corn, we believe that swee
t corn should be defined based on its use as a vegetable and on the pr
esence of one or more genes that increase sugar levels in the endosper
m.