THE TOMATO TEXT

are available. Nitrogen Nitrogen is very important to insure the growth of vine without which a good crop may not be expected. Lands vary more widely in nitrogen content than in phosphorus and potash. Sandy soils are commonly deficient in this element and often difficult to keep supplied. Here liberal applications are needed. Up to a hundred pounds[5] of actual nitrogen may prove profitable where other conditions justify. Heavier soils, well managed and manured during rotation, require less nitrogen and fair results may be obtained with no fertilizer where investment must be kept to a minimum. Form of nitrogen to be used is largely a matter of economy though nitrate for part of it may be desirable early in the season when soil is cold and nitrification slow. Nitrate is desirable for side dressing but even here ammonia and other forms are now considered suitable when the soil is warm. Failure to Set Fruit Why do tomatoes sometimes run to vine with failure to set fruit? This is an old, old query and, since 1918, has been, directly or indirectly, the occasion of more research projects than any other horticultural topic. Kraus and Kraybill[6] set the ball a-rolling with a paper which called attention first to the observations of Klebs in Germany in which he emphasized the fact that external conditions influence conditions within the plant which in turn influence performance--a veritable chain of causation. Kraus and Kraybill then undertook to relate performance (vegetative growth and fruitfulness) to internal conditions, chiefly carbohydrate and nitrogen content of the plant tissues. These, in turn, were traced back to treatments applied to the soil. They suggested four combinations of vegetation and fruitfulness in plants as follows: 1. Non-vegetative and non-fruitful. Plants whose carbohydrate supply has been cut off, say by removal of leaves which make carbohydrates. These plants were low in carbohydrate and high in nitrogen. 2. Vegetative and non-fruitful. These plants were well supplied with both carbohydrates and nitrogen. They were of the sort we describe as having "run to vine." 3. Vegetative and fruitful. These plants were well supplied with carbohydrates, but not so liberally supplied with nitrogen, thus, providing a balance between the two that was favorable for a good crop. 4. Non-vegetative and non-fruitful. These plants had ample opportunity for carbohydrate making, but were underfed with nitrogen and so could not perform well in either vegetation or fruit-making. Kraus and Kraybill conclude that there are certain balances between these two groups of compounds--nitrogenous and carbohydrate--which determine the nature of the plant's performance--whether there will be too little vegetative growth to permit a crop, whether the plants will "run to vine" or whether they will show good growth of both foliage and fruit. From experiments in the same field, using definite amounts of nitrate of soda per plant, Work[7] concluded that while adequate carbohydrate supply is necessary for fruiting, excess carbohydrate did not, in itself, occasion unfruitfulness but was more likely to represent an accumulation of material unused by reason of deficiency in some other factor--often nitrogen. It was shown that nitrate of soda does not injure tomatoes until a concentration in the soil is attained which is strong enough to plasmolyze the cells, that is to withdraw water from them by osmosis. Nor were a wide variety of nitrogen and moisture and manure treatments sufficient to induce the Bonny Best variety to "run to vine." Some varieties are subject to this trouble, mostly of the large, late types. Murneek[8] has shown that the fruitfulness of a plant may greatly affect its internal condition, its vegetative performance and its later setting of fruit. A heavy load of developing fruit, with limited soil resources, tends to limit growth and setting. Removal of fruit induces renewal of vegetative growth and of fruit setting. Failure to set fruit favors vigorous vine growth. This failure may be traceable to various causes. (1) To damage to floral parts as the blasting of the pistil by heat and drouth. Flowers of some varieties show tendency toward elongation of pistils with subsequent failure to develop normal fruit. Smith and Howlett have shown that environmental conditions as well as heredity influence this elongation. (2) To injury by insects as thrips. (3) To the character of the variety used, the Bonny group being very slightly susceptible to failure from over feeding with nitrogen while some late sorts readily "run to vine." (4) Shortage of nutrient elements as nitrogen or phosphorus or others. (5) Lack of adequate light or short day. In such cases, there may be excess of nitrogen for current need with resultant over-development of leafage. Thus, excess vegetative growth may be a result as well as a cause of poor setting. Phosphorus Fertilizer experiments fairly generally point to the frequency with which phosphorus is the limiting factor among nutrients in tomato production. MacGillivray[9] has studied the phosphorus content of the various parts of the plant, concluding that this element is important throughout and not alone in seed making or in rapidly growing parts as has been believed. Hepler and Kraybill[10] found some years ago and others more recently have confirmed the influence of liberal phosphorus treatments upon earliness. [Illustration: FIGURE 5.--Effect of omission of phosphorus from complete fertilizer in Western New York.] Potash The potash requirement of the tomato has not been as thoroughly studied as the requirement for the other two major elements. It is thought that potash has a part in building up sugars into more complex carbohydrates. The consensus of fertilizer experiments suggests that potash is less important on most soils than phosphorus and nitrogen but that if these elements are in good supply, increased yields from potash are likely. Lanham in Texas was unable to find a relation between potash fertilization and resistance to shipping hazards. Stable Manure Stable manure has long been recognized as useful for tomatoes. It is generally considered better to apply it to the preceding crop or at least the preceding fall than to use it just before setting of plants. If spring application is necessary, it is better to use well rotted manure. Stable manure is low in phosphorus. An approximate statement would be that 10 tons of manure is roughly equivalent to one ton of a 6-3-6 fertilizer. Thus, 1,000 pounds of 18% superphosphate would bring the analysis to 6-12-6 which would be generally regarded as a good balance. A recent publication[11] from Pennsylvania emphasizes the value of manures and of phosphorus. Placement and Side Dressing Recent experiments have shown the desirability of placing fertilizer close to but not in contact with the roots of the young plants. When newly set and before new roots have developed is the time when nutrient material close at hand is needed to give the plant a vigorous send-off. Transplanters have been devised with attachments to place the fertilizer in bands at each side of the row of tomatoes and about two inches deep. Recent experiments, notably by Sayre[12] of New York, have shown the advantage of dissolving fertilizer materials in the water used for transplanting tomatoes. One combination of materials consists of ammo-phos, 14-48, 2 parts and potassium nitrate, 1 part. Five to eight pounds of this mixture are dissolved in 50 gallons of water and about 1/4 pint or 1/2 cup is applied to each plant, usually by the transplanting machine. There are other suitable mixtures of nutrients for this purpose. A very small investment in starter solutions has shown material increase in total yield. The practice places immediately available nutrients in the soil at the time and place to be of maximum usefulness to plants that have been severely root-pruned and have not yet had opportunity to rebuild the root system. [Illustration: _Courtesy Campbell Soup Co._ FIGURE 6.--Cultivating and side-dressing tomatoes.] Another critical stage in tomato growth comes when much fruit has been set in the clusters and demands upon plant and soil are especially heavy. At this stage, side dressing with nitrogen is helpful in maintaining plant growth and providing resources for growth and maturing of fruit. On sandy or nutrient-deficient soils, more than one side dressing may be advisable. Sodium nitrate is commonly used but other materials are suitable after the soil has warmed up. Side dressing with fertilizer in solution has been recommended recently by Tiedjens of New Jersey. III THE BEST IN SEED IS NONE TOO GOOD A tomato crop may be much poorer than the seed from which it grows but it can be no better. The tomato seed is short-oval and flattened in shape, covered thickly with short silky hairs. The embryo or baby plant is coiled in a spiral and imbedded in the endosperm (reserve food supply). Three or four years is generally given as the life of the seed but it often remains viable much longer--up to 10 or 12 years in extreme cases. Good seed should germinate 85% to 90%. Tomato seed sprouts readily, requiring fairly warm temperature, say, 70 deg. to 75 deg. F. for best results. It germinates very slowly at 40 deg. to 50 deg. F. Breeding Being a major vegetable crop, the tomato has received much attention from plant breeders. Objectives sought include good cannery type, resistance to the fusarium wilt and other diseases, better greenhouse forms, improved general market and home garden sorts, and varieties adapted for arduous conditions such as hot and dry summers or very short growing seasons. The tomato is largely but not wholly self pollinated and pollen is not carried far. Thus, it is not difficult to breed to practically a pure-line condition. Tomatoes for seed are usually ground up and the seed and fine pulp are separated from the skins and coarse material by screening. The juice, fine pulp and seeds are allowed to ferment from 24 to 48 hours, or until the jelly-like pulp is readily washed away. After washing, the seed is dried in thin layers and stored. A bushel of tomatoes may be expected to yield 2-1/2 to 4 ounces of seed and an acre of tomatoes, from 100 to 225 pounds. These vary greatly according to varieties and conditions. Wellington[13] and others have shown that first generation seed from crosses of suitable varieties show a marked increase of vigor (heterosis or hybrid vigor) over either parent or over the later generations. This fact would seem to offer possibilities in practical use, but it has not thus far proved of value. Selection Methods Many growers find it profitable to save their own tomato seed. The plant is an annual, the important characters are quite readily observed and natural crossing is not serious. For these reasons, the enterprise is not as difficult as with most vegetables, although, if done well, it makes heavy demands in labor and care at a time when the grower has much else to do. The first step in selection is to establish clearly the ideal to be sought, recording it in detail on paper for future reference. Selections should be made on the basis of the plant, not of the individual fruit. It is the plant that is reproduced and the seed from "crown clusters" is no earlier than seed from later settings. The field should be searched soon after blooming time and plants that appear promising should be marked. These plants should be examined three or four times as the season advances, and markers pulled from plants that do not measure up to the desired standard. Suppose ten plants remain; all fruits from each of these may be saved, keeping the seed of each plant separate. All or part of the seed may be planted in separate rows the next year for further selection and to note which parents best transmit their excellent points. If only a small amount of seed is required, direct selections may be made for use in planting for the general crop. If a larger amount of seed is required, seed from one or two of the best plants should be planted in multiplication plats. Off-type plants should be removed from such plantings, but otherwise all the seed may be saved for use. Repeated selection results in constant improvement until the stock becomes a "pure line" or practically so. Lindstrom of Iowa has led in research on the genetics of tomatoes, chromosome relations and mode of inheritance. Many scientific papers deal with inheritance methods and results. The Yearbook of Agriculture (U.S.D.A.) for 1937 contains a valuable chapter on tomato breeding. It may also be had as Yearbook Separate 1581. Certification As with certain other kinds of seeds, certification service for tomatoes has now been set up in several states. Certification is a most useful incentive toward care in breeding and handling and affords valuable assurance to the buyer. It is necessary to know just what is guaranteed by the certificate. It is at the same time wise to be informed as to the inclusiveness and methods of the certification. The Ideal Variety In breeding for better varieties of tomatoes, the following are some of the characters to be sought: (1) A vigorous vine which is necessary to produce abundant fruit and to protect from sunscald. (2) Resistance to disease especially to fusarium. (3) High productiveness with moderate number of fruits per cluster--say, 5 to 8. [Illustration: FIGURE 7.--Types of tomato interiors. 1, 5. Small fruited sorts. 2, 6, 9. Bonny Best. 3, 7, 10. Chalk Jewel. 3, 7, 11. Stone. 4, 8. Earliana. 12. Ponderosa.] (4) Evenness of maturity. This is somewhat out of line with the nature of the tomato but much could be accomplished toward the goal of varieties that make their crop and are gone, eliminating long picking periods and the drag of inferior fruit toward the end of the season. The so-called determinate habit of some varieties such as Pritchard is a step in this direction. (5) Size suitable for expected use and for market demand. Greenhouse tomatoes are generally smaller than those for cannery. Uniformity of size is increasingly important with wide-spread use of the lug-box pack and of small consumer cartons. (6) Globular to oblong shape is desirable for market but is less important for cannery. Form should be symmetrical, even and smooth. (7) Color should be deep and rich, fully and evenly developed, inside and out. Red is generally preferred to pink. The difference between red and pink tomatoes does not reside in the flesh but in the presence of yellow pigment in the skin of the former while the skin of the latter is without pigment. Yellow tomatoes are also extant. [Illustration: FIGURE 8.--The Earliana tomato. A picture of a single fruit cannot adequately describe a variety. 1-3. Rough types, common in older strains. 4. Typical interior. 5, 6. Stem end. 7-9. Good type resulting from selection. 10-12. Pointed-round type occurring frequently in improved strains. A. Unusually large cluster. B. Typical Earliana cluster showing compound branching. C. Unbranched cluster of Bonny Best for comparison.] (8) Skin should be thick and tough. This safeguards against damage on the way to market and favors ease of peeling. Those saladists who serve sliced tomatoes with skins unremoved, may call for a thin, tender skin but this practice finds no encouragement from discriminating partakers. (9) Flesh should be abundant in thick walls with a minimum of watery pulp surrounding seeds. In general, a structure of many small cells is desirable. Varieties _Earliana._--The earliness of this old and popular variety outweighs its demerits where this character is required. The past ten years have seen material improvement. Earliana is early, of small vine, with small leaves and leaflets. Clusters are compoundly branched, with many fruits. The fruits are of medium size, deep oblate, cross section often elliptical rather than circular. There are many rough irregular fruits, varying in this respect with breeding and conditions of growth. Color is red, not too deep and tending to be poorly developed at the stem end. Interior consists of many small cells with thin walls. _Bison._--represents a group of varieties bred for rigorous climates of our most northerly states. A. F. Yeager formerly of North Dakota, later of Michigan, now of New Hampshire has led in this development. _Victor._--is a new variety bred originally by Yeager but introduced by K. C. Barrons of Michigan. It affords smoother, deeper and better colored fruits about as early as Earliana. It is determinate in habit and shy in foliage, increasing danger of sunscald. Rich soil and ample moisture are needed for its best development. _Bounty_ and _Home Garden_ are similar. _Penn State._--Penn State, developed by C. E. Myers of Pennsylvania, is not as early as Earliana. It is similar in fruit characters though distinctly better in color and shape. It is marked by short branches (determinate habit) and is designed to give an early crop to be followed by prompt abandonment of the planting. It is not to be confused with Penn State Earliana. _Bonny Group._--This group embraces our leading second early varieties widely used for home garden, greenhouse, market and cannery in the north. It includes _Bonny Best_, _John Baer_ and _Chalk Jewel_ with many additional names and with much confusion of characters among them. Bonny Best is second early and of medium plant growth. Fruits are deep oblate to flattened globe, even and smooth, of good red color, with few large, thick-walled cells. [Illustration: FIGURE 9.--Marglobe plant.] Varieties and strains of this group vary in growth and yield, in size, shape and earliness of fruit and in suitability for greenhouse, market, cannery and juice. _Stokesdale_ and _Scarlet Dawn_ are meritorious newer names in the group. _Marglobe._--This variety was developed by the late Dr. F. J. Pritchard from a cross between Marvel, a French variety lending resistance to fusarium and Globe, an old variety of fine size and shape. It is widely used, north and south, for market--green or ripe, for cannery and to some extent, for forcing. [Illustration: FIGURE 10.--Marglobe fruit.] Marglobe is a midseason variety, with large vine and foliage, resistant to fusarium and nailhead spot. Fruits are nearly globular, shapely and smooth, medium to large, scarlet red, with medium number of thick walled cells. Marglobe is rather subject to deep radial cracks. _Pritchard_ is of the general type of Marglobe but is earlier, with short branching habit and resistance to nailhead rust and to fusarium, and, perhaps, is less subject to cracking. _Greater Baltimore_ is used chiefly for canning in long-season districts. It is late, with large vine, large flat fruits of excellent scarlet red, outside and in, with many thick walled cells. _Indiana Baltimore_ is a variant widely grown in the mid-west for cannery. _Rutgers_ was developed by L. G. Schermerhorn at the New Jersey Experiment Station for fine juice and canning characters--color, flavor and substance. Growth is vigorous and yields are heavy; fruits are large, flattened and well colored. _Gulf State Market_ is a second early shipping tomato, generally harvested green. It is flattened in shape, of well developed pink color and good interior. _Comet Group._--These trace mostly to English or other European origin and are increasingly used for greenhouse and for staking