Cereal Crops Induced by Changes in Their Environment.
Prof. T. L. Lyon, Cornell Univ.
Whether or not plants adapt themselves to changed climatic or soil influences during the life of an individual and to what extent, if any, this is operative in producing new strains, varieties or even species is a matter of interest both to pure science and to agricultural science. It is, moreover, a subject that has received comparatively little clarification from exact experiment, although it has been quite widely discussed. Some of the Experiment Station work in this country furnishes data bearing upon the subject, in spite of the fact that almost none of It was planned with this object in view.
THAT MODIFICATIONS OCCUR IN PLANTS
WHEN CARRIED FROM ONE ENVIRONMENT TO ANOTHER.
Seed of two varieties of corn, Snowflake White and Early Yellow Rose, was obtained from Shenandoah in western Iowa and grown two years in central Nebraska. It was then planted at the Experiment Station in eastern Nebraska beside the same varieties, the seed of which had been obtained from the crop grown at Shenandoah the previous year. In this way seed of the same varieties grown, in the one case in Iowa continuously, and in the other in central Nebraska for two years, were tested under the same conditions, so that if any change had taken place in the habits of growth of the variety during its residence in Nebraska it could be detected.
The following table shows the difference in the Iowa and Nebraska corns. The dimensions and weights of plants were obtained by measuring and weighing ten plants from each plot. The yields per acre were obtained from the entire plot.
MODIFICATIONS INDUCED IN CORN BY ITS ENVIRONMENT.
|Snowflake White.||Early Yellow Rose.|
|Nebraska Seed.||Iowa Seed.||Nebraska Seed.||Iowa Seed.|
|Height of stalk, (inches)||89.2||100.3||92.9||96.2|
|Height of ear, (inches)||34.7||43.5||37.7||38.7|
|Length of shank, (inches)||5.5||7.4||5.3||7.4|
|Number of leaves,||12.5||13.7||12.6||13.0|
|Number of ear nodes,||6.8||7.7||6.8||7.1|
|Weight of stalk, (grams)||202.5||266.5||174.0||229.7|
|Weight of ear, (grams)||269.4||303.7||238.0||285.0|
|Total weight., (grams)||471.9||570.2||412.8||465.2|
|Ratio stalk to ear,||1 : 1.33||1 : 1.14||1 : 1.37||1 : 1.02|
|Leaf area, (sq. inches)||1066.0||1262.0||1001.0||1035.0|
|Yield per acre, (bushels)||73.7||68.7||68.1||62.1|
|Date of tasseling,||Aug. 1||Aug. 6||Aug. 2||Aug. 4|
The most marked changes are in the Snowflake White variety, where as the result of two years growth in central Nebraska, the stalk had decreased almost a foot in height; the ear is 8.8 inches lower down on the stalk, and the shank almost two inches shorter, while the plants have an average of 1.2 less leaves.
The weight of the stalk is heavier in the corn grown from the Iowa seed, and the ear on the Snowflake White is heavier, but on the Early Yellow Rose the Nebraska seed produced a slightly heavier ear. The proportion of the ear to the total weight of the plant is much higher in the Nebraska corn. It is also significant that the Nebraska corn has an average of almost 100 square inches less leaf surface. Plants growing in a drier climate usually have less leaf area than those growing under more humid conditions. The yield of grain was greater from Nebraska corn.
An experiment giving similar results was conducted with wheat. Turkish Red seed wheat was obtained from the Ohio Experiment Station in eastern Ohio, the Iowa Station in central Iowa, and through the Kansas Station was obtained a sample from central Kansas. These samples and one of Turkish Red wheat that had been grown at the Nebraska Station for three years were sown on contiguous plots of land. The record of growth shows great differences in the habits of these four strains of what was, without doubt, originally the same wheat. That the Nebraska and Iowa seed were originally the same is certain, for the Nebraska seed had been obtained from the Iowa Station three years before. The Ohio seed had been raised there only one year, and probably came from the Iowa Station.
MODIFICATIONS INDUCED IN WHEAT BY ITS ENVIRONMENT.
|Kansas Seed.||Nebraska Seed.||Iowa Seed.||Ohio Seed.|
|Date of Sowing,||Sept. 9||Sept. 9||Sept. 9||Sept. 9|
|Stand in fall,||Good||Good||Good||Good|
|Stand in spring,||Good||Good||Good||Good|
|Rust,||Very little||Very little||Much||Much|
|Date of ripening,||June 25||June 27||July 2||July 3|
|Yield of grain per acre,||29.1 bu.||27.5 bu.||22.3 bu.||23.1 bu.|
|Weight of grain per bu.,||64.2 lb.||62.2 lb.||56.9 lb.||58.9 lb.|
The winter of 1899-1900 was a very favorable one for winter wheat and a comparison of the stand in the fall and spring showed that there was no appreciable loss from winter killing.
The Iowa and Ohio wheats rusted and lodged badly, while the Nebraska and Kansas wheats did not suffer in this way. The Kansas wheat ripened a little earlier than the Nebraska and both of these before the Iowa and Ohio wheat There were eight days difference between the earliest and latest ripening grain.
The growth was much ranker in the Iowa and Ohio wheat than in Kansas and Nebraska, and this with their later ripening, probably accounts for the greater rusting and lodging of the former. It is also in line with the results obtained with corn.
In the cases of both corn and wheat, the vegetative portion of the plant as compared with the grain has decreased in amount, when grown in a region of lighter rainfall, and the plants have become earlier maturing.
MODIFICATION DUE TO THE DEFINITE EFFECT OF ENVIRONMENT.
The nature of the modifications produced in the wheat and corn, by removal to a less humid climate, agree exactly with the differences found in plants of the same kinds and species as they occur in humid and sub-humid regions. The question arises, have these changes in the plant taken place as the result of natural selection in the progeny of the plants when they changed their habitat, or are they the result of the definite effect of environment upon the plant itself? It will be noted that the changes in the corn were acquired during two years growth in a new locality, and that the wheat took on its new habits in the three years it was raised in Nebraska. In neither cereal was there a large elimination of plants through any selective process, natural or artificial. The wheat seed from Iowa produced only twelve bushels of wheat the first year in Nebraska, but the small crop was due to winter killing and not to drought. The second year it produced twenty-one bushels, and the third year twenty-three bushels. While it thus showed evidence of adapting itself to the climate, this adaptation could not have been due entirely to the preservation of individuals that had varied from the Iowa type, as so large a proportion of plants could not have been expected to vary in one direction.
This was equally true of the corn, which came to our attention through the fact that it yielded well during the two years it was grown in the locality to which it had been brought.
In order to show the normal percentage of individuals that vary five days from the average in time of ripening, which was the difference between the Iowa and Nebraska wheat, I have taken fifty families of wheat plants from the Nebraska Experiment Station wheat breeding nursery where notes were taken showing the date of ripening of each plant, and have calculated the per cent of plants in each family that varied five days earlier or later than the average date of ripening. (I use the term family to mean all of the progeny of a single plant.) These tabulations have been made for me by Mr. Alvin Keyser from the crop of 1903, in which year there was a greater range in the time of ripening than in any other during which the wheat breeding experiments have been in progress. Mr. Keyser finds that the percentage of plants ripening five days earlier than the average was 7.2, and that 13.5 per cent ripened five days later than the average.
Even should natural variation produce as high as thirty to sixty per cent of plants ripening five days earlier, there is no reason why these alone should have been perpetuated, for although the conditions were unfavorable to the later maturing plants, they were not so rigorous as to entirely destroy them, as is clearly shown by the fact that the Iowa wheat, ripening five days later than that from Nebraska, produced twenty-two bushels to the acre.
The conclusion seems unavoidable that the modifications induced in these crops are the direct effect of environment.
MODIFICATIONS ACCOUNTED FOR BY
TRANSMISSION OF PREVIOUSLY MODIFIED CHARACTERS.
In the experiments with wheat and corn before mentioned, the modifications become more pronounced each year, indicating a tendency on the part of the plant to adhere to its old habits of growth and other qualities, but a continual influence on the part of the environment to change it.
The same thing is observable in other experiments where seed was carried from one locality to another.
Shepperd and Ten Eyck1 report an experiment in which twenty-three samples of seed wheat grown at the North Dakota Station were compared with seed of the same varieties that had been grown at the Minnesota Station for from one to nine years, but all of which had been raised at North Dakota immediately before being taken to Minnesota. It was found that the home grown seed yielded more than the other except in a single instance, and the table of yields that they give indicates quite plainly that the longer the wheat had been grown in Minnesota the less it yielded, when brought back to North Dakota.
SHOWING LOSS OF PRODUCTIVENESS PROPORTIONAL TO LENGTH OF RESIDENCE ELSEWHERE.
|Kind of Seed.||Yield
|8||North Dakota, 3 to 9 years,||21.6|
|Direct from Minnesota,||18.6||3.0|
|5||North Dakota, 2 years,||29.0|
|Direct from Minnesota,||27.7||1.3|
|4||North Dakota, 1 year,||16.2|
|Direct from Minnesota,||14.1||2.1|
|6||North Dakota, 2, 3 and 9 years,||32.4|
|North Dakota, 1 year,||29.5||2.9|
|23||North Dakota, 2, 8 and 9 years,||25.1|
|Minnesota or North Dakota, 1 year,||22.66||2.44|
It is a matter of very common observation in Kansas and Nebraska and also in portions, at least, of Iowa that well bred strains of corn brought from states farther east continue to improve each year for several years after their introduction.
|1. North Dakota Station, Rpt. 1900, pp. 64-66.|
"Corn brought south from higher latitudes becomes later and later and later each year for several years after its introduction, the plant grows taller, and generally the proportion of trashy weavil eaten or otherwise unmarketable grain becomes less than during the first year of growth in the south."
The same thing may be observed when the imported wheats grown at the Nebraska Station are traced for several years after their importation. The following table shows the dates of ripening of the Nebraska and Iowa Turkish Red, and also of a Russian wheat called Yaroslav, for the years 1900 to 1904 inclusive. The former year was the first in which the Iowa wheat and the Yaroslav were grown in Nebraska, and the table, therefore, furnishes a means of comparing these with the Nebraska Turkish Red during the first five years of their growth in that state.
SHOWING THE GRADUAL ADAPTATION OF WHEAT TO A NEW ENVIRONMENT.
|Date of Ripening.|
|Turkish Red, Nebraska,||6/27||6/24||6/21||7/9||7/13|
|Turkish Red, lowa||7/2||6/27||6/23||7/9||7/13|
An examination of the table shows both of the alien wheats to be becoming relatively earlier in their time of ripening, as compared with the Nebraska wheat. It also shows a difference in the degree of adaptability of the two, the Iowa wheat becoming early maturing more quickly than the Yaroslav.
This tendency on the part of wheat and corn to change from year to year cannot be due entirely to natural selection, although that probably does play some part, but, as has already been pointed out, this must be small. The chief effect must be plant adaptation, as the direct result of environment on the plant. However the fact that the process of adaptation is cumulative may mean an inheritance on the part of the off-spring of the characters acquired during the previous generation.
MODIFICATIONS SUFFICIENT TO FORM NEW STRAINS OR VARIETIES.
These modifications resulted in strains of wheat and corn having qualities sufficiently distinct to entitle them to be considered, as different varieties, and this came about in a very few years. The question arises, do modifications arising from the definite effect of environment proceed to the extent of forming new varieties?
There can be no doubt that the continued enc ida sefr [sic] plant in a new environment will in time produce a new variety. Webber in writing upon this subject says1:
|1. Ala. State Experiment Station. Bul. 134.|
"Indeed, it is a well recognized fact that different soils, climates, altitudes and locations have an effect on the plant, and lead to certain characteristic variations."
He also quotes Darwin as saying:
"Variations of all kinds and degrees are directly or indirectly caused by the conditions of life to which each being, and more especially its ancestors, have been exposed."
While there can be no doubt that varieties of plants are frequently the result of their environment, it has been commonly held that changes have been effected through natural selection of those off-spring which, varying from their parents, have assumed characters or habits that better fitted them for existence under the conditions in which they had to live.
It would seem that as these varieties change so readily under a climate different from that to which they have been accustomed that they may with the same ease have assumed their present qualities as the result of their previous environment. It is also reasonable to suppose that since striking modifications are produced by the direct effect of environment, that the varietal characters due to the environment are doubtless the result of modification in a large degree, although natural selection has in some cases been the agent.
To offset the cases just cited, it is well known that varieties of crops differing considerably from each other in appearance, time of ripening, yield, etc., may be grown in the same locality for years without changing their appearance or habits, provided no crossing occurs.
It would thus seem that the effect of environment in modifying plants is not to bring them all to a dead level, but only to effect those whose habits of growth are at variance with the requirements of the conditions.
THE SAME ENVIRONMENT MAY PRODUCE DIFFERENT MODIFICATION IN DIFFERENT PLANTS.
Modifications may take place in different ways as the result of the same environment. For instance, resistance to summer drought may be acquired through any one or more of several modifications.
1. Yearbook of the United States Dept. of Agriculture for 1896.
(1) Early maturity, by which the plant ripens before the excessive heat and lack of rainfall has dried the soil to a point where further growth is prevented or seriously curtailed.
(2) An increase in the root development, making it possible for the plant to obtain a larger proportion of the moisture in the soil.
(3) Structural changes such as the thickening of the leaf, or of the pallisade cells, or other modifications which result in decreasing the transpiration.
(4) An adjustment of the habits of growth of the plant by which it can temporarily cease growth when the moisture supply is insufficient, and resume when a rain replenishes the supply of soil moisture.
A certain class of plants will usually undergo about the same modifications in adapting themselves to a region of light rainfall, and probably the same is true in respect to other environments.
The small grains, for instance, usually acquire the habit of ripening early when transferred to a dry climate, but it is also quite probable that they undergo modifications of tissue or root development. This is surmised from the fact that durum wheat which has been grown for generations and probably centuries in semi-arid regions produces crops in Kansas and Nebraska nearly as large as winter wheat which ripens two weeks earlier, and yields much more than common spring wheat that ripens at the same time. There must be some way other than early maturity by which durum wheat contrives to yield well on a dry soil. Shepperd and Ten Eyck have shown that durum wheat possesses a much more extensive root system than common wheat growing under the same conditions, and it is doubtless owing to this modification that it is so strongly drought resistant.
Of the plants that have developed large root systems alfalfa is the most notable example, but Turkestan and Samarkand alfalfa seem to have increased their drought resistance over common alfalfa by reducing the transpiring surfaces, and protecting these surfaces by means of hairs. To what extent adaptation and to what extent seed variation has operated in increasing the extent of alfalfa roots it is impossible to say.
The cactus is perhaps the most notable example of a modification in structure to meet the condition of aridity, while buffalo grass is a striking example of a plant having the ability to cease growth when moisture is scarce, and to begin again when the supply is increased.
THE IMPORTANCE OF CONSIDERING PREVIOUS ENVIRONMENT IN CONDUCTING VARIETY TESTS.
The examples already cited show that a great difference may exist between plants of the same variety which have previously been grown under different conditions. A striking example of this is to be found in tests of varieties of corn conducted at the Nebraska Station during the last three years, in which corn of fifteen varieties was grown from seed which in the case of each variety came from different sources. The variations in yields between seed of the same varieties amounted in several cases to more than ten bushels per acre, and are consistent, in that the seed from the locality most similar in climate and soil to that in which the test was made proved almost uniformly superior, thus showing the advantage it derived from partial adaptation.
SHOWING THE EFFECT UPON ITS PRODUCTIVENESS OF THE LOCALITY IN WHICH SEED IS RAISED.
|Yield per acre in bushels.||
|Silver Mine,||Saline County, Neb.||70.0||76.1||73.0|
|Snowflake White,||Lancaster Co., Neb.||84.8||74.5||79.6|
|Early Yellow Rose,||Saline County. Neb.||67.9||75.1||71.5|
|Reid's Yellow Dent,||Pawnee County. Neb.||87.1||63.4||75.2|
|Reid's Yellow Dent,||Neb. Experiment Sta.||79.5||65.0||72.2|
|Silver Mine,||Saline County, Neb.||76.1||76.1|
|Snowflake White,||York County, Neb.||73.7||73.7|
|Early Yellow Rose,||York County. Neb.||68.0||68.0|
|Leaming,||Buffalo Co Neb.||95.2||69.8||82.5|
|Boone County White,||Otoe County, Neb.||76.2||76.2|
|Silver Mine,||Washington Co Neb.||61.3||61.3|
|Nebraska White Prize,||Saline County. Neb.||89.2||79.0||84.1|
|Washington Co., Neb.||82.1||79.0||80.5||+3.6|
|Hogue's Yellow Dent,||Neb. Experiment Sta.||67.6||67.6|
|Saline County, Neb.||65.0||65.0||+2.6|
|Nebraska White Prize,||Saline County, Neb.||79.0||79.0|
|Washington Co Nab.||63.4||63.4||+5.6|
|Silver Mine,||Saline County, Neb.||76.1||76.1|
|Washington Co., Neb.||61.3||61.3||+14.8|
|Iowa Gold Mine,||Buffalo Co., Neb.||61.5||61.5|
|Washington Co Neb.||60.9||60.9||+.6|
Where seeds of different varieties are collected at random, and carried from one region to another in which the climate or soil is essentially different, there can be little information of value obtained from the results. It is true that climatic conditions change more rapidly from the Missouri River westward to the mountains than in perhaps any other portion of this country, and that hence the differences in the yields of crops from divergent environments are probably greater than they would be in the states farther east, but the same principle will hold true elsewhere, even if its effects are less pronounced.
It would seem to be necessary to raise the different varieties under the same conditions for a number of years before strictly comparable results can be obtained. It is easy to do this with small grain in which the danger of crossing varieties is slight, but with corn it is nearly impossible. It would seem that a variety test of corn in certain portions of this country amounts only to a test of the localities for seed production from which the seeds were brought, unless these localities resemble each other in soil and climate.
In the co-operative tests of varieties of corn conducted by about one hundred farmers in Nebraska for four years it was found that the size of ear produced in the eastern sections of the state was on the average from one-third to one-half larger than in the western portion.
The number of ears to the bushel (70 lb.) in each section was as follows:
SHOWING SIZE OF EARS PRODUCED IN DIFFERENT LOCLITIES.
|Section Number.||Ears per Bushel.|
This shows quite a difference in the type of corn adapted to different portions of the state, and while the differences are doubtless greater than they would be in most regions yet they certainly indicate that under such conditions the results of variety tests with corn are of very limited application.
In reporting a variety test it seems to me to be essential to state the source of the seed of each variety, and the number of years it has been raised under the conditions in which it is now being grown.
THE PRACTICE OF CHANGING SEED.
The plan of changing seed of crops from time to time has long been a popular one with farmers, and seems to be in some favor with horticulturists, but is generally decried by experimenters with field crops. The results of experiments with this practice are, in general, unfavorable to it both in this country and in Europe. Some of the experiments have already been cited, and these have in the main been unfavorable to the use of seed brought from a distance. Other experiment. dealing with this subject may be noted.
|1. Ala. Expr. Sta. Bul. 134.|
Seed corn grown in Illinois was planted at the Alabama Station beside the same varieties grown in Georgia, Alabama, Virginia, Delaware and Tennessee. The experimenter finds a difference in their habits of growth, and concludes:1
"Varieties of corn from north of the Ohio River usually give smaller yields in Alabama than corn grown farther south. Seed corn from about the same latitude as that in which it is to be grown appears to be as good as that from further north, provided it is as well selected, and maintained as pure as the imported seed."
It seems likely that the factor in this case which operated against the northern grown seed was its early maturity which prevented it from taking advantage of the long growing season at the disposal of the southern corn. It is well known that the early maturing varieties of corn do not yield as heavily as late maturing varieties. That the northern corn matured earlier than the southern is apparent from the words of the author.
"Corn brought south from higher latitudes becomes later and later each year for several years after its introduction, the plant grows taller, etc."
It is evident that the northern grown seed does not make as rank a growth, and thus has not the assimilating and elaborating facilities that the southern plants have.
|2. Maryland Experiment Station. Bul. 96.|
Stabler2 makes some very interesting observations on sweet corn in Maryland. He says, speaking of Connecticut seed in Maryland:
"A sweet corn that has always been grown on low ground near the sea in a humid climate, and in highly manured, intensely cultivated soil—the conditions in Connecticut—will not produce as well on the high, dry hillsides of central and western Maryland as a corn that has been grown and selected for a series of years to suit similar conditions."
He also says that a corn carried from a rich soil with plenty of moisture to a drier and less fertile soil curls up and stops growing much quicker in time of drought than does the "deeper rooted native varieties." He thus implies also that corn adapted to a dry climate roots deeper than one having been raised in a moist one.
|1. Maryland Experiment Station. Bul. 14|
Hayward1 at the Maryland Station also tested wheat from Kansas in comparison with the same varieties grown at the Maryland Station for some years. Six varieties were used. The results were slightly in favor of the Maryland wheats.
|2. Connecticut State Station, Annual Rpt. 1889, p. 282|
Johnson2 planted in Connecticut seed of Evergreen sweet corn grown in Michigan, Nebraska and Connecticut, and also Early Crosby from Ohio and Connecticut. The notes show no difference as to date of tasseling. The Nebraska corn had a larger proportion of ears to stalk than any other, but the stalks were fewer, and if the plants were the same size, the fewer stalks would account for the larger proportion of ears. The quality of the Nebraska corn was poorer than that of the others. There was no uniform and constant difference in the proteid content, or other constituent. The most significant feature of the experiment was that the principal differences were between the corn from Nebraska as compared with that from the other states, instead of between corn from Connecticut and other states. No determination of yield were made and hence the length of the growing season made no difference. Apparently the habits most strongly affecting the plants were those acquired as the result of residence in a humid or sub-humid region.
|1. Missouri Experiment Station, Bul. 15.|
Waters1 reports an attempt to compare a number of varieties of wheat, oats and potatoes, using home grown and northern grown seed of each variety. Seed was obtained through commercial firms which proved very unsatisfactory and practically nullified the experiment. Missouri grown wheat yielded better than Kentucky grown, and potatoes from Vermont and Wisconsin yielded much better than those from Missouri. Speaking of wheat the author says:
"It is the custom of many of our best wheat growers who have to deal with the rich alluvial soils along our rivers to change their seed frequently, for that grown upon thinner upland soil, claiming that wheat after having been grown upon this rich bottom land for a number of years acquires a habit of producing so rank a growth of straw as to fall down badly, while this difficulty is obviated by the change from poorer to better conditions."
It will be noticed that the wheat was supposed to acquire this habit in several generations under the conditions named, which agrees with the idea already advanced that modifications become more pronounced with each succeeding year until they come into equilibrium with the environment.
|2. Ontario Agr'l College & Expt. Farms Rpt. 1908, p. 123.|
Experiments in which oats are brought from one locality to another show in general a lower yield from the imported oats. A rather marked exception is reported by the Ontario Station2 in which oats from Missouri yielded more in a series of years than the home grown seed.
A number of instances can be given in which imported varieties of grain have yielded better than local varieties that have been grown in the same region for a number of years.
A striking case of this kind is the Turkish Red or Turkey wheat imported into central Kansas by the Menonites in the early seventies. Previous to the advent of this wheat the varieties raised in that region were the soft winter wheats brought there by settlers from states further east, and which had never been grown in a semi-arid region. The Menonites came from southeastern Russia and brought with them this seed already adapted to a region of light rainfall and intense summer heat. For several years after its introduction this wheat met with much opposition from the millers, because its hardness prevented them from milling it to advantage, but it yielded so much better than the wheat from the eastern states that its production increased in spite of the lower market price. Finally the mills accommodated their processes to the hard wheat, and now it is the variety raised almost universally in Kansas and Nebraska.
The Fife wheat of Minnesota and the Dakotas is really of Russian origin instead of Scotch, as commonly believed, and therefore already adapted to its new environment by years of residence in a continental climate.
The Kherson and Sixty Day oats furnish another example of a similar kind. These oats from a region having a rainfall of 16 to 18 inches annually have universally produced more grain per acre than any variety previously tried in central and western Nebraska and Kansas.
Another, but somewhat more doubtful case, is that of the Crimean wheat imported into Kansas and Nebraska a few years ago. It was thought that the Turkey wheat raised so long ago in that region was deteriorating, and that the introduction of new seed from the region originally producing this wheat would be desirable. Millers and others interested in the matter imported a large quantity of seed and sold it in Kansas and Nebraska.
It has been widely stated that the imported seed known as Crimean gave greater satisfaction than that which had been raised in this country for a longer time, but I am somewhat doubtful whether the improvement was in its productiveness or its quality.
|1. Nebraska Station Bul. 89, Kansas Station Bul. 128.|
The yields of Crimean wheat compared with Turkish Red at the Nebraska Station and the Kansas sub-station located at Hays, Kansas do not indicate a greater productiveness for the Crimean wheat than for the Turkish Red1.
YIELDS FROM IMPORTED AND DOMESTIC SEED WHEAT OF THE SAME VARIETY.
|Yield per acre.|
HAYS STATION, KANSAS.
Success or failure with seed from a new locality will depend most largely upon the degree to which the new seed is adapted to the locality into which it is introduced. It will be better than the old seed in proportion as it meets with this requirement, and as the old seed failed in this respect.
Thus the northern grown corn when carried to Alabama yielded poorly because it was not adapted to the long growing season. It did not make sufficient growth of foliage to enable it to elaborate the largest possible amount of food, and it matured too early to permit of this. On the other hand, the corn brought from Iowa to Nebraska failed for the very opposite reason. (See Table I.) It used too much time and material in the growth of stalk, and left too little of each for the formation of grain. There would than seem to be an optimum development of stalk and leaf for each environment, in order to produce a maximum of grain. This is why one variety will yield best in one year, and another variety in another year. Seasons change to suit first one variety and then another.
The same thing may be observed in the wheats brought from Iowa, Ohio and Kansas to Nebraska. (See Table II.) The Iowa and Ohio wheats produced too much foliage and stalk, the Kansas wheat produced less stalk and foliage than the Nebraska grain. Wheat or oats grown for a number of years in a dry climate do not grow so tall as those raised in a more humid one, and this lesser growth is a disadvantage when they are brought into more favorable conditions, as shown by the following tables.
KHERSON OATS TESTED AT THE NEBRASKA STATION IN 1905.
|Source of Seed and Time Raised There.||Yield per Acre.|
|Grown continuously at Station,||81.2|
|Grown in eastern Kansas two years,||80.2|
|Grown in western Kansas three years,||79.1|
|Grown in central Nebraska four years,||70.3|
|Grown in western Nebraska one year,||72.8|
TURKISH RED WHEAT TESTED AT THE NEBRASKA STATION IN 1903.
|Source of Seed.||Yield per Acre.|
|Grown continuously at Station,||31.8|
|Grown in western Kansas until 1902,||31.1|
|Grown in eastern Kansas until 1902,||29.6|
|Grown in eastern Kansas until 1899,||31.3|
|Grown in Iowa until 1902,||27.3|
|Grown in Iowa until 1899,||31.6|
|Grown in Ohio until 1902,||28.1|
The tests of wheats in 1900 (Table II) show that in certain years the western seed may produce better than the home grown, but such seasons are those which resemble in climate the region farther west.
The factors determining adaptation are not entirely climatic. Soil exercises a potent influence in this respect. The remarks of Tracy, Waters, and Stabler regarding this have been quoted. Of the varieties of corn grown at the Nebraska Station, those from Washington County, Nebraska, were grown on very rich soil, and this undoubtedly accounts in large measure for the poor yields they gave on less fertile soil.
The plant accustomed to a very fertile soil will make too rank a growth to permit the production of much grain when planted on poor soil, while the plant raised for many years on a soil lacking in fertility or moisture will fail to avail itself of all of the nutriment it might obtain from a rich soil.
This, of course, does not mean that a well bred strain will not in time prove valuable under new condition, but the length of time it must be grown before it becomes useful will depend upon the extent of the difference between its old and its new environment, and upon the natural adaptiveness of the plant.
QUALITY OF GRAIN AND ADAPTATION.
The quality of the grain is quite another property from that of yield. The plant will tend to preserve the quality of its grain. Thus northern grown oats when carried south generally produce plumper berries the first year than they do the second. Hard wheat carried to a moist climate produces harder kernels the first season than it does the second. The quality of the grain thus becomes modified to conform to its new environment, and when this new quality is objectionable it is termed "running out."
Potatoes get smaller, oats produce a thinner berry, wheat grows softer, the ears of corn become smaller and less regular, and then we say they are "running out." This may be due to the climate, or to the soil, or to both.
Deterioration in the quality of seed may be rectified temporarily by securing seed from a region in which a better quality is produced, but decrease in yield can be remedied only by securing seed better adapted to the environment in which it is to be raised, or by obtaining a strain that has been better bred and raising it long enough to adapt it to its new environment.
The introduction of Crimean wheat resulted in a temporary improvement in the quality of the grain in parts of Kansas and Nebraska because it came from a region capable of producing a better quality of grain. Turkish Red wheat produced a larger yield than wheats grown there before because it had been raised under a somewhat similar environment, and had become adapted to it, while the wheats already tried had never adjusted themselves to the conditions. Turkish Red now yields better than Crimean because it has been raised longer in its new home, and has poorer quality for the same reason. Quality of grain is a more strongly adherent property than is productiveness.
THE RELATION OF ENVIRONMENT TO THE BREEDING OF PLANTS.
If I may be excused for digressing for a moment from my subject into the very fascinating realm of plant breeding, I might say that the natural conclusion from the preceding statements would be that it is desirable to breed a strain of any cereal under, as nearly as possible, the conditions in which it is to be grown; that the more strongly bred a strain is the longer it will retain its quality under the new environment, and that possibly, the better suited it is for one set of conditions the more difficult it will be to adapt it to those that are radically different. I make the last statement with some hesitation in view of the fact that Reid's Yellow Dent, which is perhaps the oldest variety of corn bred to one type, has been remarkably successful in Iowa, Kansas and Nebraska. It is, however, a medium early, small eared variety, in which respects it meets the requirements of that region.