« AnteriorContinuar »
374. Score Card For Dent Maize. I
Furnish each student with a sample consisting of ten ears of maize.
1. Trueness To Type Or Breed Characteristics, 10 Points.—The ten cars in the sample should possess similar or like characteristics, and should be true to the variety which they represent.
2. Shape Of Ear, 10 Points.—The shape of the ear should conform to the variety type. Ear should be full and strong in central portion and not taper too rapidly toward the tip.
3. Purity (a) In Grain, 5 Points.—Color of grain should be true to variety and free from mixture. For one or two mixed grains, a cut of one-fourth point; for four or more mixed grains, a cut of one-half point should be made. Difference in shade of color must be scored according to variety characteristics.
(b) In Cob, 5 Points.—An ear with white cob in yellow maize or red cob in white maize, should be disqualified or marked zero. This mixture reduces the value of the maize for seed purposes, indicates lack of purity, and tends towards a too wide variation in time of maturity, size and shape of grains.
4. Vitality Or Seed Condition, 10 Points.—Maize should be in good seed condition, being capable of producing strong, vigorous growth and yield.
5. Tips, 5 Points.—The form of tip should be regular; grains near tip should be of regular shape and size. The proportion of tip covered or filled must be considered. Long pointed tips as well as short flattened or double tips are objectionable.
6. Butts, 5 Points.—The rows of grains should extend in regular order over the butt, leaving a deep depression when the shank is removed. Open and swelled butts, depressed and flat butts, with flattened glazed grains, are objectionable and must be cut according to the judgment of the scorer.
7. Grains (a) Uniformity Of, 10 Points; (b) Shape Of, 5 Points.—The grains should be uniform in shape and size, making it possible to secure uniformity in dropping with the planter, and consequently a good stand. The grains should also be not only uniform on individual ear, but uniform in color and true to variety type. The grains should be so shaped that their edges touch from tip to crown.
8. Length Of Ear, 10 Points.—The length of ear varies according to variety, type, and the characteristics sought for by individual breeders. Uniformity in length is to be sought for in a sample, and a sample having an even length of ears should score higher than one that varies, even if it be within the limits. Instructor will set limits for length of ears of sample according to variety, allowing a variation of one inch. The sum of the excesses and deficiencies in inches shall constitute a cut in points.
9. Circumference Of Ear, 5 Points.—The circumference of the ear will vary according to the variety and the latitude. The circumference of the ear should be in symmetry with its length. An ear too great in circumference for its length is generally slow in maturing, and too frequently results in soft maize. Instructor will set limits for circumference of ears of sample according to variety, allowing a variation of one-half inch. The sum of the excesses and deficiencies in inches shall
1 The score card of the Iowa State College slightly modified. Iowa Bui. 77 (1904). constitute a cut in points. Measure the circumference at one-third the distance from the butt to the tip of the ear.
10. (a) Furrows Between Rows, 5 Points. — The furrows between the rows of grains should be of sufficient size to permit the maize to dry out readily, but not so large as to lose in proportion of grain to cob.
(b) Space Between Tips Of Grains At Cob, 5 Points.—This is objectionable, as it indicates immaturity, weak constitution and poor feeding value.
11. Proportion Of Grain To Cob, 10 Points.—The proportion of grain is determined by weight. Depth of grains, size of cob, maturity furrows and space at cob, all affect the proportion. In determining the proportion of grain to cob, weigh and shell every alternate ear in the exhibit. Weigh the grain and subtract from weight of ears, giving weight of grain; divide the weight of grain by the total weight of ears, which will give the per cent of grain. Per cent of grain should be from 86 to 87. For each per cent short of standard, a cut of one and one-halt points should be made.
375. Determination Of Commercial Grades Of Maize. — Give each student two to four pounds of maize of two or more unlike samples and have him determine the proper grade. (367)
(a) Per cent of water: grind a sufficient amount of maize into a coarse meal and
determine per cent of water in thirty grams by drying to constant weight at 102° C
(b) Color: determine percentage of color in 500 grains by count.
(c) Damaged grains: determine percentage of rotten, moldy or otherwise un
sound grains in 500 grains by count.
(d) Broken grains and dirt: determine on the basis of weights the percentage of all
broken grains, meal, dirt, chaff and other foreign material in two or more pounds.
376. Collateral Reading.
Natural Distribution of Roots in Field Soils. By F. H. King. Ninth Ann. Rpt
of the Wis. Agr. Expt. Sta. (1892), pp. 112-120. Varieties of Corn. By E. L. Sturtevant. U. S. Dept. of Agr., Office of Expt.
Sta. Bui. 57.
Manual of Corn Judging. By A. D. Shamel. New York: Orange Judd Company (1903).
Xenia, or the Immediate Effect of Pollen in Maize. By H. J. Webber. U. S Dept. of Agr., Div. Veg. Phys. and Path. Bui. 22 (1900).
Methods of Corn Breeding. By C. G. Hopkins. 11i. Agr. Expt. Sta. Bui. 82 (1902).
Selecting and Preparing Seed Corn. By P. G. Holden. Iowa Agr. Expt. Sta. Bui. 77 (i9°4)
The Maintenance of Fertility. By Charles E. Thome. Ohio Agr. Expt. Sta. Bui. 110 (1899).
Ten Years of Experiments in Corn Culture. By R. J. Redding. Ga. Agr. Expt.
Sta. Bui. 46 (1899), pp. 73-75. Modern Silage Methods. The Silver Manufacturing Co., Salem, Ohio. Maize. Origin of Cultivated Plants. By Alphonse De Candolle. New York:
D. Appleton & Co. (1902), pp. 387-397.
377. Relationships.—The tribe (Avenae) to which the oat (Avena sativa L.) belongs differs from the tribe (Hordeae) to which wheat, rye and barley belong, in having the inflorescence in panicles instead of in spikes, and in having a crooked awn on the back of the flowering glume, instead of a straight awn at the end. To this tribe belong few economic plants. Arrhenathemm avenaceum Beauv. is somewhat extensively cultivated in France under the name of Ray Grass. It is only sparingly cultivated in America under the name of Tall Oat Grass. Velvet
Grass (Holcus lanatus L.) is also occasionally sown as a pasture grass.
378. The Plant.—The habit of growth of the roots is similar to that of wheat. The culms are somewhat larger in diameter and of rather softer tissue. Environment has a greater influence upon
Nodes of oats: A, exterior view; B, cross- length of Culm of OatS than of
section of straightcuim; c, cross-section winter wheat and rye. Height of
culm varies from two to five feet:
becomes erect by the growth on its lower
side of the sheath node, not the culm probably the average height is node' three and a half feet. The leaves are more abundant, the blade broader, and the ligule more pronounced than in wheat.
The Ohio Station found during seven years an average of one pound of grain to two and one-tenth pounds of straw when fertilizers were used, and one of grain to two of straw when no fertilizers were used.1 The Illinois Station has found as high as two and seven-tenths pounds of straw per each pound of grain,2 and as low as one and two-tenths pounds in different seasons under otherwise like conditions.3 Kansas Station found a variation of from four and one-tenth to one and two-tenths pounds of straw to one pound of grain due to season.4 In general, the more favorable the season the more fertile the soil, and the later the variety or the later the seeding the greater is the proportion of straw to grain.
379. Inflorescence.—A typical panicle is nine to twelve inches long, contains from three to five whorls of branches and bears about seventy-five spikelets. The branches arise from alternate sides of the rachis and vary in length and position; thus the panicle may be open or closed; symmetrical or one-sided. Each spikelet is at the end of a flexible pedicel of variable length. The spikelet contains two or more flowers; only two usually mature, the lower one always developing into the larger grain. The outer glumes are membraneous and
. _ . . A spikelet of oats: I, outer
considerably larger (three-fourths to one giUmes; 2, lower flower; inch) than the flowering glume. The color 3, upper flower; 4, mdi
. ment of third flower
of the latter varies from yellow to reddish brown and black. The flowering glume of the lower flower usually partially encloses that of the upper flower. The awn, when it occurs, is on the back (not at the tip) of the flowering glume, and usually occurs only in the lower flower of the spikelet. The palea is smaller than the flowering glume and enclosed
1 Ohio Rpt. 1896, p. 142.
within the latter. The organs of reproduction are quite similar to those in wheat . (56)
380. The Grain.—The oat kernel, except in hull-less varieties, remains enclosed in the flowering glume and palea. These parts are usually referred to as the oat hull, but are entirely different from the hull of maize (228) or the bran of wheat. (64) In this book the caryopsis of the oat will be called the kernel, and the kernel plus the hull will be called the grain. In general form and structure the oat kernel is similar to the grain of wheat, but is rather more elongated, while the pericarp is characterized by its hairy surface. Richardson found in an average of 166 varieties that 100 grains weighed 2.5 grams, with variations from 1-75 to 3.75 grams per hundred grains.1
381. Relation of Hull to Kernel.— The quality of oats depends principally upon the proportion of hull to kernel. The per cent of hull depends both upon the variety and upon the conditions of growth, varying from at least twenty to forty
Magnified section of
portion of oat kernel: p, pericarp; /, testa; a, double
row of ateurone five per cent . American varieties contain on an
cells; x, endo
average about thirty per cent of hull and seventy per cent of kernel. It has been demonstrated that there is no necessary relation between weight per bushel or shape of grain and the per cent of kernel or food value. The Illinois Station, working during five years with from thirty to sixty varieties, the seed of which was from various sources, but the crops all grown under like conditions, found that generally varieties with long, slender, comparatively light grains had the largest per cent of kernel.2 The Ohio Station, working with seventy varieties
1 U. S. Dept. of Agr., Div. of Chem. Bui. 9.
2 11i. Buls. 7, 12, 19 and 23.