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ing, but in practice it is not generally desirable to treat the seed in any way.
272. Method of Testing Seed. If the plumule and radicle of the embryo are carefully exposed by means of a sharp knife, these parts will be white and plump. Any discoloration or wilting is evidence of injured vitality. To determine vitality definitely, seed should always be tested before using. This may be done by any method
Homemade germinating apparatus : consists which furnishes proper condi- of a shallow tin basin, which is given two tions of heat, moisture and air.
coats of mineral paint to prevent rusting.
The bottom of the basin is covered with A satisfactory method is to fill water and a small flat-bottomed saucer of any receptacle similar in size porous clay is placed inside. Seeds are
placed between two layers of moist blotand shape to a dinner plate ting paper or flannel cloth. A, complete; with sand. Pour on water until B, section. (After Hicks.) it covers the surface of the sand. Gently drain off water. Place grains in the moist sand, thoroughly covering them, and
cover receptacle by inverting a similar one over it to prevent too rapid evaporation and place in a temperature of 80° F. If ninety-five per cent of the seed fails to germinate in five days, the seed is unsatisfac
tory. If shelled grain is to be tested, Cigar box used for testing germina. take 1oo grains after thorough mix
tion of maize. Grains may be placed ing. If ears are to be tested, take between moistened newspapers or cloths, preferably flannel. (After three grains from each of twenty-five Holden.)
to fifty ears, taking a grain from butt, middle and tip. In some cases it may be desirable to test each ear separately by taking ten grains from each ear. In no case should an ear be used in which nine out of the ten grains failed to germinate under conditions named.
273. Seed from Different Parts of the Ear.-Grains on an ear equally represent inherent qualities of the plant which produced them. They should, under favorable conditions, produce plants having similar characteristics. The butt grains being larger and the tip grains smaller, differences in the food supply exist which it was thought might modify the ability of the seed to survive unfavorable conditions or cause variation in the vigor with which the young plant was started upon an independent existence. It has also been suggested that the grains on the middle of the ear are more likely to be fertilized with pollen from the same plant and that this closer breeding might tend to decrease the yield from plants grown from such grains. In no case have any considerable differences in yield been obtained from using grains from different parts of the ear. The results given below seem clearly to demonstrate that there is no advantage in planting grains from any special portion of the ear, provided equal stands are obtained. Average Yield per Acre of Seed from Different Parts of Ear
The Kansas Station found that under field conditions eightysix per cent of the butt grains, ninety per cent of the middle grains and seventy per cent of the tip grains produced plants. The Iowa Station found that when all the grains of an ear
1 Kan. Bul. 64, p. 238.
Iowa Bul. 68, p. 278.
were used in the corn planter, the number of grains dropped at one time varied from one to six grains, the planter dropping three grains to the hill sixty-six times out of a hundred. When only the middle grains of the ear were used, the planter dropped two grains eight times and three grains ninety-two times to each hundred hills. Since uniformity of stand is essential to maximum yield, it is therefore good practice to discard the largest of che butt and the smallest of the tip grains. It is also found that in order to secure uniformity of stand it is essential to select ears having grains of uniform size. It was found that when long and short grains were mixed together, the planter dropped three grains seventy-five times out of one hundred; while when planted separately with proper plates for each, the planter dropped three short grains ninety-five times out of one hundred and three long grains ninety-two times out of one hundred.
274. Limited Distribution.—That there is a wide difference in distribution of maize as compared with other cereals is shown in the following table giving average production in million bushels by continents for five years, 1898-1902 inclusive:
The fact that sixty-six per cent of all the maize raised in the United States is grown in seven maize surplus States—Ohio, Indiana, Illinois, Iowa, Missouri, Nebraska and Kansas—is a further indication of its limited distribution. It is this limited distribution, coupled with the fact that maize will produce about twice the food nutrients of any of our other cereals per acre, that makes lands especially adapted to the culture of maize command relatively high prices.
275. Causes Limiting Distribution. Among the causes limiting successful cultivation are temperature and sunshine, rainfall and physiographical features, including soil. It is only when these several factors are properly combined that the culture of
maize becomes commercially successful. The absence of any one may limit successful production. If, for example, the area between the 70° and 80° July isotherm be followed around the world in the northern latitude, it will be found that throughout the larger part of its course the rainfall is insufficient at those times of the year when it is most needed by the maize plant;
Variation in amount and distribution of normal monthly rainfail, see map (276). For
May, June, July and August, total normal rainfall is: Lincoln, Nebraska, 15.7 inches; Tuscola, Illinois, 14.4 inches ; Columbus, Ohio, 13.2 inches; Western England, 10.7 inches: Middle Germany, 8.6 inches ; Southeast Russia, 7.2 inches.1 The great maize belt lies between the longitudes of Columbus, Ohio (83° 0' W. Long.), and Lincoln, Nebraska (96° 45' W. Long.).
or, where the rainfall is sufficient, physiographical feacures prevent the culture of maize on a large scale.
The so-called “corn belt” of the United States appears to have the best combination of temperature, sunshine, rainfall, soil and topography for the production of maize of any considerable area in the world.
1 Rainfalls for Lincoln, Tuscola and Columbus are from twenty-five-year averages of the United States Weather Bureau. The European figures are from Davis' Elementary Meteorology.