Black Mexican Sweet Corn

The so-called Black Mexican sweet corn is actually a sweet version of a New England dent, presumably the same strain cultivated by the Iroquois as "black puckers". It was used in breeding for its excellent quality, and later for the peculiar inheritance of its color. When crossed with a white or yellow variety, either as seed- or pollen-parent, some of the crossed seeds were black, dotted with black, or had no perceptible black coloring. The true form has 8 rows of kernels. It was sometimes confused, and mixed, with another variety having 10-12 rows. "Aztec Black" is a later name for the same ancient variety.

It is interesting to note that slate-colored forms of the giant Cuzco corn behave similarly when crossed with white and yellow types.

Gregory: Massachusetts Board of Agriculture 1858 p 330
Several collections of excellent sweet corn were exhibited by S. A. Merrill, of Salem, and others, but among them all we did not find any specimens of the Black Mexican. Of ten varieties, which we tested the past season, this was decidedly the sweetest. The ear is rather below the average size, and matures somewhat late, the kernels when ripe being of a rich, dark, purple color, but when in the milk but slightly tinged with purple. The Black Mexican is prolific, will bear close planting, and we can confidently recommend it to the gardeners and farmers of Essex.— J. J. H. Gregory, Chairman.

American Agriculturist, 22: 92 (March 1863)
New, Useful or Ornamental.—Mexican Sweet Corn, new and pure (no variety of table corn will compare with this in sweetness; a great acquisition.)
James J. H. Gregory, Marblehead, Mass. Advertisement

Burr: The Field and Garden Vegetables of America (1863)
Black Sweet. Slate Sweet. Plant, in height and general habit, similar to Darling's Early; ears six to eight inches in length, uniformly eight-rowed; kernels roundish, flattened, deep slate-color, much shrivelled at maturity. Early.
    The variety is sweet, tender, and well flavored; remains a long period in condition for use; and, aside from its peculiar color (which by some is considered objectionable), is well worthy of cultivation.

Burr: Garden Vegetables (1866)
Black Sweet, or Mexican. Slate Sweet. Plant, in height and general habit, similar to Darling's Early; ears six to eight inches in length, uniformly eight-rowed; kernels roundish, flattened, deep slate color, much shrivelled at maturity. Early.
    The variety is sweet, tender, and well flavored, remains a long period in condition for use, and, aside from its peculiar color (which by some is considered objectionable), is well worthy of cultivation.

Vick's Illustrated Monthly, January 1878 p 25.
Also, for three years, we have bought the Black Mexican Corn for seed, and each year it has come up almost white, just a black kernel here and there. Once it came up true to seed. If you can tell us the reason we shall be greatly obliged.—G. A. Cassidy, New York City.

Documents of the Assembly of the State of New York, 4: 159 (1885)
14. BLACK MEXICAN. Synonyms — Black Sugar; Slate Sweet, Burr. We have here another instance of two types being grown together under one name. The second form we will describe under the name Black Sugar, in another section. Ears six to eight inches long, and about one and one-half inches in diameter, cylindrical even to tip which is rarely well filled. Kernels broader than deep, rounded, crinkled, compactly set, of a slate black color. Plant about five to six feet tall, bearing its ears six to eight inches from the ground.
    This is the variety described by Burr in 1866, under the name of Black Sweet.

Tracy: Experiments in Crossing Corn, Tomatoes, and Carrots. Eighteenth An. Rep. State Horticultural Society of Mich., (1888)
In 1881, by starting it in pots we secured silk on three or four plants of Cuzco corn. This is a very late maturing species from Brazil which grows much taller than ours, with much more brittle leaves which are split into threads by our winds. The ear is short, nearly as thick as long, and the grain is much larger and proportionately broader, being in size and shape much like the common chestnut and perfectly smooth on the outside. The grain is made almost entirely of starch which is very white and flour like. The tassels had all been cut from the Cuzco as fast as they appeared, and the only pollen I had to use was some of Black Mexican. I used this freely and frequently, and as a result obtained two quite good ears, many of the grains being black and wrinkled like sweet corn, others being white but wrinkled, still others being white and smooth like the variety. In 1882 the white wrinkled grains were planted where there was little chance of mixture. The tassels were carefully removed as they appeared, and in due season the silk was fertilized with Early Minnesota pollen. The result was quite a lot of ears, some showing all sweet grains, some nearly all of the Cuczo type; but I think none of them black, although some of them showed considerable red. The best ear was selected and the sweet grains planted in 1883 and the silk again fertilized with Early Minnesota. This season there was considerable black corn, there being much more color than in 1882. The best two ears were selected and planted and left to fertilize themselves. There was much less color shown this season than any year previous. In 1885 the best were planted and no color appeared. In 1887 the best ears were planted and no color showed. In 1888 the best two were planted, and this season a good many grains were as black as the Mexican and some ears are as much marked with red or black as is the ordinary red blazed. I could not find that there was any red or black within a mile. Where did this color come from if it was not "in the blood?"

Hays: Corn improved by cross-fertilization and selection (1890)
In 1888 Mercer Yellow Flint was planted at the station not far from Black Mexican sweet-corn; at harvest one to several black grains were found on several ears of the Mercer Flint; a dozen of these dark-colored grains were planted in 1889 in such a way that the plants were out of the reach of the pollen from other varieties. Ears were produced which proved that the Black Mexican corn had fertilized dark-colored grains on the ears of Flint the previous year. Besides the Yellow Flint and the Black Sweet grains, there were Yellow Sweet, Black Flint, White Sweet, and White Flint grains on nearly every ear. The appearance of White Sweet grains is explained on the assumption that the Black sweet-corn had at some previous time been mixed with a very light-colored variety of sweet-corn, while the White Flint grains may have come from a previous ancestor of White Flint, or even White Sweet. Moreover, the fact that on several of the ears were grains of sweet-corn of a reddish or flesh-colored tint, peculiar to a variety of sweet-corn called Early Narragansett, may indicate that this variety was among the ancestors of the Black Mexican Sweet.

Plumb: Indian Corn Culture, p. 33 (1895)
Black Mexican; also known as Black Sugar and Slate Sweet: Ears 6 to 8 inches long and about l 1/2 inch in diameter, cylindrical, tip rarely well filled; cob white, small, 8 rowed. Kernels slate-black, broad, crinkled, compactly set, tender and sweet when ripe. Plants about 6 feet tall. A medium early, of the best quality, that has been known for many years.

Halsted: Corn Breeding (1903)
Plant breeding has been a leading feature of the work in the field, supplemented by that of the greenhouse. During the year a new variety of sweet corn has been established, which resulted from crossing the "Black Mexican" upon the "Egyptian." This combination has produced a variety with good-sized plants, and ears of satisfactory size and number of rows of graining upon the cob. The color of the green corn when ready for market is a rich pink, and therefore especially attractive. Progress has also been made in developing a variety of corn that may have the grains mixed in the ear—pink and white—and with a special tendency to produce more than two ears to each plant. During the season a cross has been secured between the "Black Mexican" and the "Country Gentleman" for future development by selection.

Halsted: Experiments in crossing sweet corn (1904)
It was strikingly noticeable last season that the "Country Gentleman" was abundantly fertilized by the "Mexican" while the reciprocal cross was apparently the rare exception. It was almost impossible to find an ear of the white sort without few or many dark grains while among all the "Mexican" ears only sufficient white grains could be found to plant but a few hills the present year. Hand pollination was successful with the "Gentleman" and ears were thus obtained that showed the cross in every grain. The color of these crossed grains was a shade of lead color and in this respect is quite different from the cross that developed into the "Voorhees Red."

Webber: Correlation of Characters in Plant Breeding. American Breeders Association 2:73-83 (1906)
In the pure Black Mexican: the silks are white or light green, the stamens light green, and the glumes light green, commonly, but occasionally with a few reddish, longitudinal stripes. In the pure Stowells Evergreen the silks range from dark reddish purple to light pink, the stamens are reddish purple and the glumes reddish purple or with marked purplish stripes. It will be noted that the combination of colors here, in comparison with the kernel color, is just the opposite from what would be expected, as the light amber-colored kernels of the Stowells Evergreen would rather be expected to be combined with greenish or light silks, stamens, glumes, etc., and vice versa.

Emerson: Latent Colors in Corn (1909)
A cross of Queen's Golden popcorn with pollen of Black Mexican sweet corn resulted in numerous ears, the individual grains of which—something over 17,000 in all—varied from nearly yellow, through yellowish brown, greenish brown, and purplish brown, to nearly black, the color in any particular case being due to the combination of the strong, medium, or weak bluish purple of the aleurone with the dominant yellow of the underlying endosperm.

Parker: Varieties of corn used by the Iroquois. N.Y. State Museum Bulletin, Issues 144, Nov. 1, 1910
Black sweet, osoⁿgwud'dji deutgoⁿ'negaide˘ - black puckers

The Vegetables of New York, Volume 1, Part 3 p. 22 (1934)
The name Black Mexican implies that it came from Mexico: it is not mentioned by Salisbury in 1848, by Bement in 1853, or by Klippart in 1858. Under the name Black Sweet it was described by Burr in 1863. James J. H. Gregory of Marblehead, Massachusetts, listed this in 1863 in his retail catalog of garden vegetables.

Rhoades: Effect of Gene Dosate on Aleurone Colour in Maize. Journal of Genetics 33(3): 347-354. (1936)
Dotted (Dt) trait derived from Black Mexican.

McClintock: The Significance of Responses of the Genome to Challenge (1983)
In the mid-nineteen-thirties Marcus Rhoades discovered this Dotted (Dt) element in a strain of Black Mexican sweet corn. It behaved as a dominant gene that caused the otherwise very stable but non-functional a allele to mutate to new alleles that allowed anthocyanin pigment to be formed in both plant and kernel. The name Dotted, given to it, refers to the pattern of mutations that is expressed in plants and kernels homozygous for the a allele on chromosome 3 and having a Dt element located elsewhere in the chromosome complement. Small streaks of red or purple pigment appear in plants; the kernels have dots of this pigment distributed over the aleurone layer. (The aleurone layer is the outermost layer of the endosperm.)