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Report of the Botanical Department.

BYRON D. HALSTED, SC. D.

B. H. A. GROTH, PH. D.

MARION T. PLEASANTS, A. B.*

EARLE J. OWEN, M. Sc.
MATHILDE GROTH.

The research work for 1914 has been continued under the four projects approved two years ago namely: I. Heredity; II. Toxicology; III. Sap-circulation and IV. Environment.

For the study of Heredity fully 5,000 tomato and 3,000 pepper plants were grown in the breeding grounds and to these were added large numbers of crossed prairie berry plants, nine blocks of corn and several plots of beans, eggplants, soybeans, okra, etc. The season was not advantageous for large yields, but the protracted autumn drought and absence of early frosts permitted of an unusual amount of study in the field.

During the winter the greenhouse afforded an opportunity for the study of seedling growth of corn and soybeans, at different temperatures and depth of planting, under the project of environment and results indicated that some of the characters of the mature plant may be thus foretold.

Under sap-circulation it has been determined that the sweet potato plant when grown in a poisonous soil, inhibiting root storage, is able to deposit starch in the basal part of the stem.

EXPERIMENTS WITH CORN.

Nine blocks of corn were grown upon the four acres of experiment grounds, they being as far apart as possible and by taking note of the differences in time of bearing, very little mixing resulted. The blocks are reported upon below and in the order of their number in the field.

"Golden Queen" Upon "Brazilian Flour" FI.

This is a cross between a tall long-season variety of popcorn with the small slender yellow ears, frequently borne two or more to the stalk, and a stout, broad-leaved kind also late with large, stout ears usually produced singly with white grains that have a chalky endosperm. The block was somewhat uneven in season and size of plants, but finally produced a set of plants many of which were of unusual length with a range of over twelve feet down to five feet. The slender stalks, like the popcorn, bare the smaller ears with soft husks and the taller plants had the larger ears with thick closely adhering husks. Taking the block as a whole the "Golden Queen" seemed to be the most potent parent.

*Given leave of absence for a year to hold a fellowship in botany at Smith College.

1

In the present cross the evident great difference between the parents seems to have induced more or less sterility and consequent increased size of plants. It follows from this that the cross in question could not be recommended as a good one for ears but might serve well for forage. The characters of ears and grain may not be desirable. Intermediate ears between the two parents are long and slender with many rows of small flinty grains not husked with ease and possibly shelled with difficulty. This cross was made for the purpose of the study of the influence of the parents upon the size and type of stalk, ear and grains, also popability. The ears and grains have not yet been measured or the grains tested for their ability to pop.

Plate I* shows a series of ten crossed ears between sample ears of the parents, the "Golden Queen" at 1 and "Brazilian Flour" at 12. The ears are arranged somewhat in the order of their agreement in size and grain conformation with their respective parents. There are no ears that might be mistaken for the popcorn but on the other hand a few ears appeared fully like the "Brazilian Flour" in size and shape of ear and grain but with the dominant yellow color excepted. It is remarked that the intermediate, those occupying the middle of the series are larger but not broader than either parent and attractive in every particular. It is too soon to report upon the measurements of the ear and grains as compared with those of the parents. This cross between a fine example of the flinty type of corn with one of a floury endosperm illustrates something of the inheritance of those widely different characters. While the plants grown were the direct result of the cross, their grains, because of Xenia, show the offspring inheritance in the second generation for endosperm and color characters. It is found that many of the grains have only chalky endosperm while upon the same ear, other grains are flinty. This is easily shown by cutting off the tips of the grains when the ears are freshly husked and before they have become dry. The floury grains can be easily cut upon an old ear and easily distinguished from flinty grains cut only with much difficulty. Upon many ears the floury grains are decidedly larger than their flinty associates. There is much influence exerted by the mother plant upon the degree of flouriness, some ears showing a large, others a small percentage of evidently floury grains. Taken as a whole, there is near a quarter of floury grains, thus suggesting that this character is a Mendelian recessive. The nearer the ear approaches the pop parent the less evident is the flouriness and it may nearly disappear. In this variability the character in question resembles that of sweetness in which case some ears of a commercial kind or a cross may be more starchy than others and is a plant character as shown by the fact that all the grains of the ear or ears of a stalk are nearly alike in this flintiness. In the "Brazilian Flour" itself some ears approach the flinty, while others have the grains truly floury and easily reduced to powder.

It is possible that in the present cross the floury grains not apparent to the eye may be segregated by the process of popping.

*The photographs for the plates were taken by Prof. F. H. Dodge to whom many thanks are due for his skill.

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PLATE I-Crossed Corn: "Golden Queen" upon "Brazilian Flour" (F1) two quite opposite kinds in size of ear and texture of grain. The two parents are shown at the extreme right and left (1 and 12) with ten sample ears of the cross (Fi) between and arranged with regard to their likeness to the parents. Some ears (11) are extracted "Brazilian Flour" but none reproduce the "Golden Queen."

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PLATE II-Crossed Corn: Two ears of the "Golden Queen" upon "Brazilian Flour" with the upper rows of grains (F2) cut, while still soft to show that certain kernels are starchy throughout like the "Brazilian Flour," while the great majority are corneous and therefore in texture approach the "Golden Queen."

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