Scientific method in education

Author's Preface

HIS book is written with the hope of fulfilling the various needs of the potato growers of California. Many suggestions will also prove beneficial to the eastern grower. Since the potato is the foremost food plant of the American people, the author has endeavored to give in as brief and complete form as possible the much-needed and valuable information. Since the author has made a life study of this problematical plant, there are some profitable suggestions unfolded to the reader within these few pages. Such knowledge is the author's personal experience, having learned from this, the world's greatest teacher.

The book contains some interesting experiments on the plant as well as the practical culture of the potato.

A thorough study and strict observance of the instructions herein will insure the most amateurish growers of California remarkable success.

July, 1917. A. J. YOUNG, SR.

Spraying. Preparation of Bordeaux mixture and Paris Green. Insect pests. Causes and prevention of diseases.

Chapter 7. Harvesting and Marketing 85

How to grade for market. Sources of influence upon quality of the potato.

TABLE OF ILLUSTRATIONS

Page

The old home 3

A. J, Young, Sr 5

Potato bloom ready for pollination 13 '

Potato fruit and seed 17 •

A perfect two-year seedling 21

The best hill of seedlings I ever produced 27 '

A potato in good condition to plant 33

Results of planting a potato when too old 37

My 1916 field of potatoes 41

A cutting ready for planting 53

How to plant to reproduce on top of the vine 65

Potato insect pests 71

A potato affected with wilt 78

The Scottish Chief potato is the best marketable tuber known 83

Young's Early Harvest King 87

The upper bloom shows the exact time for pollination.

Chapter I

F all interesting studies of plant life, the problems confronting the potato breeder, also the nature of the plant, are the most interesting to me. There are numerous difficulties in potato breeding. He who would succeed must discover for himself these obstacles and overcome them.

I have studied the nature of the potato, have experimented, have propagated many kinds, and have grown the potato extensively for about twenty-three years, and every day there are different problems confronting me, most of which I have solved, yet there is deep study ahead and much to be learned. I have grown potatoes from cuttings, and from such cuttings have grown four crops in one year, each cutting being taken from the vine that had been grown from a cutting. The first cutting was taken from a seedling, which would make four crops without using a tuber for seed. I have learned how to grow potatoes on top of the vine, and many more interesting experiments, and find there are always new ideas presenting themselves. Some of the problems confronting the potato breeder are: In some cases it is impossible to cross one desirable potato with another which has otherwise good characteristics, because of non-production of fertile pollen. Again, he must grow a great number of varieties in order to determine which have viable pollen. The climatic and soil conditions greatly influence the production of fertile pollen. There are some varieties of potatoes whose buds drop off before opening, and some that have a few flowers open but fall too soon. There are also some whose flowers live for several days but frequently the pollen is not fertile. Again, many times when the blooms do appear and the pollen is fertile, in some cases the seed balls or fruits are seedless, and if they do have seed it does not always germinate. Instantly a question arises in our minds, "Is there a means by which we could produce this coveted fertile pollen ?" There are, however, a few varieties which generally produce viable pollen. The disease resistance of a tuber plays an important part in this matter.

After these difficulties have been overcome, the actual crossing of the plants is an easy matter. The plants to be selected for crossing should be strong and healthy, with good characteristics. The mother plant should be especially strong, having a desirable feature that is lacking in the male plant, and the male plant possessing some characteristics which would make a good cross.

There are two ways of pollination. First, nature's way, self-pollination. Second, hand pollination, of which there are several methods.

One method of hand pollination is as follows : First, the female plant is deprived of its anthers. The anthers stand erect in the center of the flower, like a cone. These flowers are then covered with paper bags with some foliage to insure moisture, for proper development. After this, in about two days, the male plants are gathered, the pistil removed and the pollen jarred onto the emasculated plant.

Potato fruit and seed.

The pistil is the small, cylindrical form in the center of the anthers. Within a week's time the blooms will have either swollen or dropped, thus determining the success or failure of this method of pollination.

Another method of hand pollination is: After the selection of the mother plant, the corolla, or inner petals, and the stamens are cut away before fully developed and then the blossoms are bagged. At the proper time for pollination, the pollen is collected from the male plant with a fine camel's hair brush and is then dusted on the mother plant. This is repeated for two successive days; that is, if the pistil has not fallen. When the fruit has begun to form, the paper bags are removed to allow free access to the air and light. When the seed balls are ripe, they are gathered and allowed to dry. They are then squeezed out, as they are liable to decay if left in the fruit.

Still there is another method, one which the Japanese are said to use, and is very simple. The flower of the male plant, when in proper condition to pollinate, is dusted by hand onto the mother plant. The plant is then covered to keep stray pollen off the pollinated flowers.

Another method, one which I have found best in my experience, one which is nearest nature's way, therefore we would conclude it to be best. I do not cut the flowers in any way, but when the flowers are to be pollinated, I limit the blooms to two bunches, and, with the use of a fine camel's hair brush, lightly dust on the pollen of the male to the mother plant. These always being desirable crosses. Before this, however, when the mother plant is beginning to bloom, I cover it with a cheese cloth. A frame can be easily made by pushing laths or sticks into the ground around the vine to keep the cheese cloth from touching it. Thus by the use of the cheese cloth the blooms have free access to the air and light, and in no way can stray pollen fall upon the blooms. The proper time for pollination is about the second or third day of bloom. The pollination is repeated for two successive days ; that is, if the pistil has not fallen. The cheese cloth should be left on for about five or six days. When the fruits are thoroughly ripe they are gathered, seeds squeezed out, washed in a cheese-cloth bag, and allowed to dry.

It is always a wise plan to select strong parent plants, because they develop larger and better seed. These seed in turn develop larger potatoes the first year from the seed than those from a delicate plant. It is of greater importance that the mother plant be strong than the male plant, and care should be taken in selecting the most vigorous ones.

This is a fact not known by most potato experts, if any. The way of determining the actual fertility of the potato fruits or seed balls without the aid of a magnifying glass: The balls are partially or wholly covered with small, white pimples. The smooth fruits are rarely, if ever, good.

I have, in selecting crosses, chosen those with about the same qualities, with the idea of im.proving them; while at other times I have crossed the opposites, with the idea of obtaining different and better qualities. These ideas are both good, providing the crosses used possess favorable points. I have noticed that the potatoes not seemingly closely related have greater affinity for one another than those which are apparently related.

I would not advise the potato breeder to use too much fertilizer on the first-year seedlings. This policy is followed by some, but is not a wise plan. The potato vines generally grow rank and scarcely any tubers are to be found. Some breeders use food material to induce variation, but the potato naturally tends to vary even if crosses within a variety

A perfect two-year seedling are used. However, after the first or second year from the seed, large vines do not indicate that such excessive top growth is opposed to the formation of tubers, as some believe. I find that large vines make large tubers and a greater quantity. But if a so-called "run out" or "stray" is found, it must be noted that the vine is overgrown and very few tubers are to be found.

In selecting the seedlings from year to year, always choose the one nearest your own ideal of a perfect potato. Keeping this in mind, select and plant for eight years ; or, if planted twice a year, for four years. By this time your potato will have reached a true-to-type one.

The seedlings must be grown several years in a comparison test ; that is to determine the best type before a definite selection is made. The discovery of a way in which potatoes are bred up to a pure strain within less time is of great advantage to the potato world.

By the use of the potato cuttings from seedling vines making four crops in one season, then the tubers produced used for early spring and fall planting for the next two years, the development would be shortened.

In comparing and selecting the seedlings each year the qualities to be kept in mind, in addition to productiveness and uniformity in size and shape, are :

1st. The largest seedling should be selected each year. By so doing the potato will have reached its highest state of development within a shorter period or will be a larger potato when developed, which is a quality the people of California want.

2nd. Select those that are hardiest, consequently less liable to disease. The vigorous potatoes are more drought or disease resistant, and by the selection of such progeny the breeder is always assured a potato of good quality and yield.

3rd. Those that are most adapted to peculiarities in climatic and soil conditions.

In cutting seedlings, it is always advisable to cut and throw away the blossom end of the potato ; that is, the bud-eye cluster. This end, when planted, is more liable to cause prongy tubers, although the tubers produced from this end are more disease resistant.

In order to insure a good development during the first year or season's planting of the potato seed, it is advisable to allow the seedling a long growing period. They require from five to nine months, depending on all conditions. It is well to plant as early as possible, if planted in the field.

SELECTION AND CARE OF THE SEED POTATO.

Chapter II

N the growing of a profitable crop of potatoes, I would say that the first important factor is that of good seed. The next of importance is good soil. Without both these necessities, a good crop of potatoes cannot be produced. Good seed potatoes are known by their yield and quality when cared for properly. Good seed will produce a fairly good crop in poor soil, but poor quality seed in the most fertile soil will not give good results.

The average potato grower is careless in that he allows his seed stock to become mixed with other varieties. This is decidedly undesirable. These mixtures are generally of a poor quality, and the grower should look to discarding them, as well as the diseased ones. This demands, or should demand, the special study and attention of the grower. Study and learn the varieties, and discard the unproductive strains! Again I would emphasize the importance of unmixed seed. If a mixture of early and late potatoes were planted, the result is, naturally, an uneven germination; and scarcely any of the late tubers are set on when those of the early varieties are ready for market. The great loss to the grower can be readily seen, and is enough within itself to pay for the good seed.

The majority of potato growers in California and elsewhere use "culls," or inferior seed. Thus doing, they invite an unfavorable quality as well as yield. The belief that is prevalent throughout the country that the average cultivated potato shows a tendency to degenerate or "run out" is true. It is quite a natural result, caused from lack of knowledge or carelessness in the selection of the seed potatoes. The inferiors are used year after year, and the resultant crops are very poor. The fact that like produces like is essentially true in the potato as well as other plant life. If the best of seed were used, planted in good soil and handled properly, this tendency of degeneration would soon be overcome, and better prices could be demanded for the better grade of potatoes. If studied closely and carefully, each variety may be found to have unproductive strains. These potatoes are generally curly topped. These should always be discarded, so that the variety grown be kept to its highest standard of development.

In my experience I have learned that strong plants produce many times the number of good tubers than the weak plants, and in some cases the poor seed does not produce any marketable tubers whatsoever. Therefore, I would say that the selection of seed should be conducted with the greatest of care.

Now arises the question, "What is good seed?" Too much stress cannot be laid on this ever-important and interesting subject, the production of good potatoes.

1st. The tubers used for seed must be strong, vigorous, and productive.

2nd. Must be pure and unmixed.

The best hill of seedlings I ever produced, being eighteen smooth potatoes, and not an ounce difference in weight.

3rd. Should be firm and with the sprouts just showing at planting time, as shown on page 33,

4th. Should have been selected at digging time. This is called "Hill Selection."

5th. Must have been carefully and properly handled.

6th. The seed should not be too ripe or mature.

7th. The seed should not show any disease whatever, or have any rotten spots.

8th. The seed must not be too old or too new.

Potatoes that have been sprouted two or three times are not the best for seed. They are too old. Each time they are sprouted they become weaker. When they are at this age, the sprouts, if there are any, are weak and threadlike. If such potatoes are planted, they will not grow, as they are too delicate to send out a top. If they do happen to grow, there will be small, pea-like tubers form just in or outside of the eyes. The seed piece may be firm, but because of the age it will not reproduce. The nature of the potato is to reproduce, so if it cannot send up a top, the small tubers will form in the eyes of the old potato. If these old tubers are opened, it will be noted that they are hollow or are water-soaked, and the quality very poor. Page 37 shows such a potato that had been planted for three weeks.

The newer seed, that with the first sprouts just showing, comes up more readily and possesses greater vitality than older seed. That is one of the serious faults of the growers in some districts of California. They use seed that is old and has sprouted badly. The sprouts are sometimes several inches long before the potatoes are planted, consequently the potatoes have not the strength left in them to make a good crop. Those plants that do come up are weak, therefore more subject to disease. In some experiments I have tested new potatoes with the sprouts just showing, and old ones that had been sprouted in soil infected with jelly-end and rot. The tubers from the new seed did not show a sign of the disease, while those of the old seed were badly infected. The new seed is more liable to be prongy or knotty, but this can be overcome by cutting away the blossom end.

Another serious fault of some potato growers is to leave culls lying on the ground from year to year. The weaker hills are always more liable to disease and always produce small tubers. If these small tubers or culls are left on the ground, the new crops and the land is bound to become infected with the disease ; and if this way of handling the crop is continued, the disease will increase with great rapidity and soon no crop can be raised.

I have noticed in a volunteer hill of potatoes, where they have lain on the ground over winter, that the center eye in the bud or blossom end is always the first one to sprout. It is this eye that produces the crop resulting in prongy tubers, and I maintain that this center eye in the blossom end is the eye that finally causes the "running out" of the potato, although it is the strongest eye and is the first to come up when planted. The grower should not, therefore, under any circumstance, allow culls to lay on the soil where the same crop is to be grown the following year. These culls cause the degeneration of the potato, breed diseases and tuber moth. If, instead, these culls were used for stock feed, either in the raw state or cooked, they would more than pay for the trouble, and the following crop would be greatly improved.

I have learned that it is wise to change the soils used for potatoes from year to year. If they are planted in peatland one year, the seed produced should be planted in a lighter, but not too light, loam the following year. The stand and yield is always increased. This is a practice not known to most potato growers.

The year 1916 I had a 98% stand, and a yield at the rate of four hundred sacks per acre. This land has been in potatoes every year for twenty-three years. I attribute this to the selection of good seed, planted at the proper time and well cared for. The field picture is shown on page 41. We would naturally conclude, then, that the value of good seed cannot be overestimated. As much cultivation is put into a 50% stand as a 98% stand, and almost the same expenditures would produce a 98% to 99% crop. The gain in the resulting crop from the use of good seed would be surprising. While the 50% stand would hardly pay expenses, with an 80 to S5% stand the grower would realize a good net profit. When potatoes are a good price, a great number of farmers buy any seed just so it is cheap, plant it, and expect a good crop. Instead, the results are poor and a very inferior quality of potatoes are produced — thus the loss of time and money. They find that they cannot obtain a good price for such quality of potatoes, so sell them at a very low price to get rid of them. This floods the market with poor quality potatoes, consequently the conscientious grower will lose indirectly to a certain degree. Then the inexperienced farmer decides there is nothing in it, so stops growing them until the price is high again, when he begins again enthusiastically with the same method of poor seed, and naturally produces the same results.

The man who makes a success in potato-growing, as in any other business or profession, is the one who has the stick-to-it-iveness. He is the one who will get the best of seed, no matter what the first cost is, and will always produce good potatoes. He will get the best price for them.

because such potatoes are very scarce. In fact, it is a hard matter to find them. That is the reason I advocate so strongly the use of good seed.

You may ask, "How will we tell good seed?" By looking at them it may be ascertained whether or not they are sound, firm, or diseased to a certain extent. But whether or not the seed will produce a good crop cannot be determined. The only way, then, is to try several varieties in your particular soil. By hill selection year after year of the best (that is, the most productive and of the best quality), your potatoes may be brought up to a high standard of development. But if the growers cannot take this time to learn the best, it is always advisable to buy of some recognized seed potato grower, or a reliable seed firm.

I have some potatoes that cannot be surpassed for peat land or damp, heavy soil, although when planted in the peat land they would not sell for marketable potatoes, as they are too large, rough, and deep-eyed. This sam.e potato, when planted on other loamy soil, makes the largest yield of any I have ever tested. They are of a good size and exceedingly good for market. It is quite a remarkable fact, the difference in size and shape in a variety of potatoes grown in different soils. Those grown on weaker, light soils are likely to be more smooth and uniform, as far as looks are concerned. When seed quality and vitality are considered, the tubers that are grown on the rich soils are far superior, though they be rough, deep-eyed, and ill-shaped. This potato, if changed to a lighter loam, will come out smooth and large ; also the yield will be greatly increased. Inheritance plays an important part in the size and shape of the tuber, yet to a great extent these factors are determined by the kind of soil, fertilizer, and care given the crop.

There is an increasing demand, for fancy table stock.

A good seed potato, in proper condition to plant.

and if the use of good seed were persisted in, the grower would be paid the higher price for the better quality potatoes, and consequently the subject of "Improvement of the seed potato" hence "The development of high grade marketable tubers" is receiving more attention, than heretofore.

The successful grower gives his most careful attention to the source of his seed supply. He either becomes an expert himself in the growing of the crop or buys of some recognized seed potato grower or seed firm. As a result his average yields are enormous in comparison to the one wha is careless in his seed selection.

The development of the best grade seed potatoes is not a perplexing problem ; however, great care, attention, good judgment, and correct methods must be persisted in year after year. If the grower has not the time to develop his own seed into the best grade — seed of the best quality and highest productiveness — he must, for several reasons, buy his seed from a recognized seed potato grower — one who makes a specialty of growing varieties of a pure, strong, and vigorous type. It is preferable to buy of one whose seed potatoes are grown on rich soil, as this seed is more vigorous and will be more disease-resistant. Thus he will obtain better results from the seed grown in this soil than that grown in lighter soils. Never obtain seed from a seedsm.an whose stock is not free from mixtures with other varieties. To insure the maintenance of their strength and vitality the seed must be kept pure. The grower's average yield of marketable potatoes should be from two to four hundred sacks per acre. This insures the buyer the best of seed.

Considerable dependence can be placed upon the appearance of the tops in hill selection. The vine with one hardy stem is always better than two or three weaker ones. When once learned, the tops will tell about the yield to expect, the size of the tubers, the number, and where they lay can be easily determined. When the grower is able to do this, he may figure very closely the yield per acre, what proportion will be of marketable size, and the proportion of culls. The tops of the potatoes will vaiy in different soils and varieties. Some will be different in color and the leaves shaped differently. Where the soil is extraordinarily rich, it will be noticed that the hills with two or three stalks have better marketable potatoes than those with one stalk. Where the soil is so rich, in a hill v/ith just one stalk, the tubers will be too large for market. If the soil is weak and light, it will be noted that the large top with one sturdy stem produces a better size than those with more.

To those who care to grow their own seed to improve them, thus raising their potatoes to a high standard of development, I advise to carefully select them at digging time. This is called "hill selection." These potatoes should be carefully dug by hand, avoiding cuts and bruises. Each man should use two cans, one for select tubers of uniform size and shape for seed, the other for marketable tubers. Each hill should be dug separately. If in a hill of potatoes one be rough, or in any way defective, this hill should not be used for seed.

The development of the potato to its highest standard has proven as interesting to me as the fascinating study of the propagation of new varieties. In my hill selection I have taken particular care in selecting only hills with an average of eleven or more uniform tubers. This eliminates all unproductive plants. In continuing this line of work an excellent strain of potatoes is always secured. The best potato growers always place emphasis upon keeping the potato true to type. If we want the best we must of necessity

The results of planting a potato when too olH tato was dug after being in the ground for ♦'

plant the best. The best strains always produce the best in plant life as well as in animal life.

To the growers of California, I cannot too strongly emphasize the necessity of pure, vigorous seed. They are largely exempt from disease ; and if the soil is infected with disease, fertilize and plant to different crops that do not breed these diseases until the soil is rid of it. When potatoes are grown again, be careful to select only the best of seed, and, with the care of the crop I advocate, the yields will be wonderfully increased.

In handling the crop the tubers should not be moved too often; however, they should not be left in piles on the field to sprout and lose their strength.

Potatoes for seed should always be "greened" when using early spring seed for fall planting. Greening is to cause them to sprout under certain conditions before planting. In other words, they are put into proper shape to grow.

The seed produced from the April planting for planting in April of the following year becomes a little old before the time to plant, and it is a difficult problem to stay their growth and preserve their strength. They are stored in a cool place until the cold weather in the fall appears. Then they are put into a dry place before the rainy season comes, and when the first sprouts begin to show they are put out to green and are left in that condition until planting time. The sprouts are generally from one-half to one inch long at this time, and are always planted with these sprouts on. The sprouts become tough, and are hard to remove. This seed, when properly handled, always insures a crop about two weeks earlier.

The importance of greening is twofold :

1st. If allowed to grow or sprout too readily before planting, too much strength is taken from the potato, causing it to shrink. Therefore, the plants are stronger, are: healthier, and more vigorous if greened, and an increase of ' yield is the result. The average increase in yield of greened over ungreened seed is, in most instances, about twentyfive per cent.

2nd. The tubers, when planted, mature in a much shorter period when greened, and can reach the market much earlier. Since it takes a shorter period to mature, the potatoes do not have as much chance to take in disease as when left in the soil longer. Again, if the seed is kept in trays and greened, they will keep longer for seed purposes than if kept in bins, sacks, or piles.

In greening, the potatoes should be placed not more than two or three inches deep, and arranged so that plenty of air and light can reach all tubers. They should be kept in a cool, dry, shady place. An open barn or shed is generally used. Seed potatoes should always be kept in moderate temperature. Some farmers' ideas of greening their seed are very poor. Their idea of greening is by the sun, never once thinking that the extreme heat is as injurious as frost. The tender potatoes just taken from the soil will stand but little heat in the sun. It is essential that they be kept in the shade.