P O T A T O P R O D U C T I O N P R O B L E M S I N S O U T H A M E R I C A ~

JoHN T U C K E R 2

Department of Agriculture, Ottawa, Canada

This paper was prepared with the thought in mind that many people working with potato problems would be interested in hearing about some of the present-day problems connected with potato produc- tion in South America, particularly as potatoes are believed to have been cultivated there as a staple crop for many centuries before they were heard of in other parts of the world.

The observations recorded here were made on a trip of four months ' duration, beginning on the first of March, 1938, and finishing at the end of June. The trip was made via regular steamer, rail, and automobile. From New York, the route taken was through the Panama Canal, south down the Pacific coast to Valparaiso, Chile, calling at Colombian, Ecuadorian, Peruvian, and Chilean ports en route, then across the Andes mountains to Argentina and Uruguay, and north to Brazil. The return trip followed the same route approx- imately, with side trips into Brazil, South Chile, Ecuador, Costa Rica in Central America, and Cuba.

Covering about 30,ooo miles in the four months ' period, it was possible to stay only a few days in some countries aad about twt~ weeks in others. During this time it was just possible to see something of the growing crops, the methods of production, potatoes as marketed locally, the imported certifieJ seed potatoes compared with the native varieties, to arrange interviews, and to secure information about local problems and of those in adjacent countries.

In the brief period allotted to the subject, it is obviously not pos- sible to go into much detail regarding the situation in all of the coun- tries visited. At the same time it would not do to attempt to generalize too freely when dealing with so wide a diversification of problem!s as exist over that vast area, running about four thousand miles north and south, and the width of the continent. By dividing the area into two zones, the tropical and the temperate, it is possible to generalize on these to some extent. For this purpose, Costa Rica, Panama,

~Contribution No. 9 from The Plant Protection Division, Production Service, Department of Agriculture, Ottawa, Canada.

2Chief Inspector, Plant Diseases.

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Ecuador, Peru, Bolivia and the northern areas of Chile and Argen- tina are included in the tropical zone, and the central parts of Chile and Argentina, together with Uruguay, in the temperate zone. Bra- zil can best be dealt with as a separate unit.

I shall deal first with the tropical zone. Potato production is con- fined to suitable locations at a height of about 5,000 feet or more in the mountain ranges, which stretch along the whole of the west coast. Three ridges of the Andes mountains in Colombia north of the Equa- tor unite at the Equator in Ecuador, continue south as a double chain to Peru, then diverge again into three parallel ridges. These join into two chains going through Bolivia into northern Chile, and Argentina, then continue south principally as a single ridge. There are spurs of mountain ranges leading east and west from the main chains and there are intervening deep valleys, and extensive plateaus along the length of the cordilleras.

There is the most amazing variation in climatic conditions in areas even a very short distance apart, east and west, all along the coast, brought about by the wide contrasts in altitude and humidity. For instance, it is only a matter of a few hours' journey, where trans- portation permits, from the almost impenetrable tropical jungle of bush, rivers and swamps, which form most of the coast line of Co- lombia and the adjacent coast line territory of Ecuador, from the land of crocodiles, tropical fruits, balsa wood and cocoa, to barren moun- tain peaks and snow caps. South of that area most of the coast line for the next two thousand miles is desolate rainless desert and dry foothills leading up to mountains and steep valleys beyond which, at a height of about ten thousand feet, there is a moderate annual rain- fall. Beyond that again there are the higher mountains and snow peaks ranging up to 20,000 feet and which drop away to wide plateaus at approximately I2,ooo feet intersected by deep canyons in which conditions are more or less tropical.

It was in this vast sierra that potatoes were first discovered and cultivated thousands of years ago, some authorities believe, and they were used and are still being used as the most common article of food by the natives. I t was in this area, too, that a well-equipped Russian botanical expedition recently discovered a whole series of distinct species differing in systemic characters and chromosome num- bers from the Solanum tuberosum, the tubers which grace our tables. Many of the new species have properties of frost and disease resist- ance which may in due time be bred into our potatoes of commerce.

As far as could be ascertained, practically all the cultivated sorts

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belong to the species Solanum indigenum. These grow at altitudes of 5,ooo-I3,ooo feet and several hundred distinct varieties have been iden- tified. They come in all shapes and colors but usually lack size, and judged by our northern standards, a great many would come under the category of culls. Most of the samples examined on the markets appeared to contain a mixture of varieties, but everything, no matter how small, deep-eyed, rough or piebald in color, appeared to have a good cash value, selling at the rate of three to ten cents a pound. The flavor ranged from poor, insipid, and even bitter, in some lots, to exceedingly good in others. All the cultivation is prac- tically done by hand labor, some using long iron-shod sticks with a foot rest attachment to enable the foot to force the blade into the ground and loosen the soil, others a two-prong type of hoe. The crop yields average about fifty bushels to the acre in most areas, but there are exceptions where yields are considerably higher.

Some varieties are made into a product called "chuno," others into "tunta," by the simple expedient of allowing them to freeze at night and tramping the water out of them as they thaw during the day. The process is repeated for a few days and the chuno is then dried off and stored. For tunta a further process of soaking the po- tatoes in pools of water for some weeks is necessary, after which they are dried off in the sun. Tunta is featherweight and is lily white in color. These products can be stored indefinitely as they will neither freeze nor mold. They have been the means of averting untold misery among the natives of the high plains on occasions of crop failures.

The potatoes are grown on plateaus and on terraced ridges on steep mountain sides under irrigation wherever possible, but always in the mountains, practically never at the coast, although there are ex- ceptions, that at the La Molina coastal experimental station in Peru, for instance.

It is unfortunate that in spite of the very low wage level of the natives and their natural love of potatoes, the cost of production is so high that many cannot afford to eat potatoes and are turning more to rice and other cheaper food products when these can be procured.

The native S. andigenum differs somewhat from our S. tuberosum in plant characteristics, the leaves are narrower and more widely spaced and the stem has lengthened internodes. The chief difference, however, is in its reaction to length of daylight, and the hardiness of some vari- eties. The native species are accustomed to conditions of almost equal day and night and produce a crop of tubers only under these condi-

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tions, and most of them require six months or more to mature. These varieties, when grown under our normal summer daylight, do not pro- duce tubers unless arrangements for shading are made to reduce the intense light to 9-IO hours daily. The growing of varieties of this species in the northern hemisphere is routine work now at potato plant breeding stations and extensive information is available on the value of certain varieties as parents for introducing frost and disease resist- ance into the S. tuberosum, group, but it seems that there is practically no information available on the value of selected varieties of our S. tuberosum group when grown under the short day condition of the tropical Andes mountain area. I t should be of interest, therefore, to see what happened to samples of Canadian potatoes which were sent into this area for test purposes.

Two crates of I IO pounds each of Irish Cobbler, Green Mountain, Bliss Triumph and Katahdin were distributed to growers in the moun- tain valleys in the vicinity of Quito, the capital city of Ecuador. A similar lot was sent to Colombia and Peru.

There was some opposition at first on the part of sanitary autho- rities to allowing entry of any potatoes from North America for fear of introducing insect pests and contaminating the native varieties with diseases unknown there, but as no pests of any kind were present on the tubers, they were admitted, but under quarantine in one case. I t is obvious, from the health conditions found in the native crops, however, that the progeny of the samples will not likely remain dis- ease-free for a long period.

The following is a brief summary of information secured in the various countries of the tropical zone.

ECUADOR :--All imported varieties made exceptionally rapid growth for this country. The local varieties take from six to six and one- half months to mature; whereas, the imported potatoes matured in approximately ninety days, and produced yields of more than thirty to one, compared with ten to one for the best local varieties. With treble the yield in half the growing period, the test was considered a most satisfactory one, and will be repeated. With a possible three crops per annum, the cost of producing potatoes in that country could be reduced considerably. The local variety, Yungara, a red skin, yel- low-fleshed variety, grown under irrigation, appears to be the most popular variety grown at present in that area.

For imported seed it is apparent that preference would be given to small size potatoes of approximately two to three ounces, for plant- ing whole. The color of the skin does not appear to be of much import-

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ance. That white flesh sorts will soon become popular, is the opinion of the principal growers there.

PERU:--The samples arrived at Lima in excellent condition on the 28th of April, and were planted under irrigation at the experi- ment station on the coast at La Molina, and at Concepcion and Tarma in the mountains. Sr. Gerado Eckert, agricultural engineer in charge of the tests, reported on the 29th of August as follows:

"Insofar as the precocity of the varieties is concerned, the test on the Coast has proved that this has been accomplished (9o-Ioo days period of vegetation). The potatoes also have good resist- ance to Mosaic and Phythophthora, the principal diseases on the Coast, with the exception of the 'Katahdin' variety, which ap- pears to be a very delicate variety as has been observed at La Molina and in the highlands (Sierra) . The best one appears to be the 'Irish Cobbler' variety. This is also the best one in the highlands. With regard to the cold, it can be said that the plants resist a temperature of 4 ~ C. below zero. Regarding 'qualitative appreciations of the harvests in the different places' and regarding the flavor of the potatoes, a complete and final report will be prepared once all the tests are harvested."

The most common varieties under cultivation in Peru are the Blanca corriente (ordinary white), Amarilla corriente (ordinary yellow'), Blanca de San Mateo, Amarilla de San Mateo, Blanca de Tarma, Amarilla de Tarma, Blanca d Maco, Chata negra, de Canta, Yana Mata de Tarma, Yurag Mata de Tarma, Chuito Tarma, Peina Tarma, Pampina T~arma, Chaucha Tarma, Chiri Mauna Tarma, Huariaca Tarma, Maguayos de Canta, Cochcas de Canta.

There are very numerous other named wild and cultivated varie- ties in Peru with local Indian names.

According to statistics for the year I929, the latest obtainable there, potato production totalled 825,864 metric tons from 285,o56 hec- tares, or less than 5 ~ bushels from each acre. The present sanitary import regulations require fumigation of all seed potatoes except mate- rial required for official tests. There are no Colorado potato beetles in South America as far as is known at present.

BOLIVlA:--The Ministry of Agriculture estimated that approxi- mately half a million bushels of seed potatoes were planted there annually. The Bolivian agronomist, Cerallos Tovar, has counted more than two hundred varieties of the species S. andigenum. The names of the most common varieties marketed are Chiar Imi!la, black skin;

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Jancko Imilla, buff skin; Laram Imilla, mauve skin; Imill'cooso, light yellow skin, bitter taste, used for chuno; Morocco, bitter, used for tunta. These are all white flesh varieties.

The price of potatoes in La Paz, the capital, averages about three cents a pound.

COSTA RIcA:--Formerly, this Central American country pro- duced, on the slopes of the mountains surrounding San Jose, the Capi- tal, more than sufficient potatoes for local consumption, and exported fair quantities to Panama and Venezuela. In recent years, yields have declined because of virus diseases and late blight. The principal vari- eties left in production are the Blue (Morada), a long, blue skin, white- fleshed variety; the Morada Blanca, white with blue sprouts; and one of unknown origin named Boston White, a round white potato. These have been grown without special selection for nearly thirty years, and there are few now produced that are much larger than walnuts. Plants are killed off prematurely with late blight. Tests have been made with so-called resistant varieties from various sources, and the best results were obtained with the Guguerrena Peon variety from Cugerres, Colom- bia. The next best was seedling 44488 obtained from Dr. Donald Red- dick, Cornell University, New York. This seedling was planted on the 23d of November, and survived until the I5th of January, giving a yield of I 5 ~ pounds, from the 5 pounds and 12 ounces planted. Bliss Triumphs were given a trial in a small way commercially this year. Some growers reported fair results. Others reported that the potatoes had blighted down early. This is a country where a reaI good blight-resistant variety would be most welcome, and that applies also to the Republic of Panama.

COLOMBIA:---Time did not permit to visit the plots at Bogata, the Capital, but it is understood that the samples sent there gave very good results.

Dealing next with potato problems in the temperate zone, it is necessary to visualize an entirely different set of conditions to those existing in the tropical zone. Potatoes are produced near the sea level; in Chile, at a latitude of S. 42~ and in Argentina and Uruguay at latitude approximately S. 340-38~ comparable to that from S. Vir- ginia-N. Maryland, U.S.A. in northern latitudes. Unfortunately all details of topography must be omitted suffice for the purpose to men- tion that the growing conditions more nearly resemble those with which we in North America are acquainted, except possibly for the fact that because of the vicinity of mountains to some of the important potato growing areas, irrigation seems to be more generally practiced there.

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CHILE :--The potato-producing area is situated about 65o miles south of Santiago, the capital, and includes the districts of Frutillar, Llanguihue, Puerto Varas, Puerto Montt and Chiloe Island. This area is admirably adapted to the production of potatoes of good quality and large quantities are exported from this area annually to several other South American countries. Apparently all the native cultivated varieties are of the species S. tuberosum and the Chileans have con- siderable support from scientists who have studied the subject, to their claim that this species originated there many centuries before potatoes were introduced into Europe and later into North America.

Due principally to the inroads that virus diseases have made into the crop, yields have been seriously declining in recent years. A survey recently conducted for the purpose of selecting suitable founda- tion stock with which to start a seed potato certification system found tbat it was now a hopeless task to attempt to secure any virus-free material there. There was plenty of good virus-free seed available in other countries but their problem was to secure it from a country that was free from late blight Phytophthora infestans (MONT) DE BARY. Strange as it may seem, that disease has never been found in Chile, although the conditions appear ideal for its development there. Fin- ally it was decided to import certified seed from Canada and multiply it in an area far removed from their potato growing districts. For this purpose about thirty tons of the varieties Green Mountain, Irish Cob- bler, Bliss Triumph, Katahdin, President, Golden and Royal Kidney were imported from Nova Scotia last year and planted under irriga- tion at an experimental station recently acquired for agronomy experi- ments at Los Anjeles situated half-way between Santiago and the potato area. The location and soil were admittedly poor for potatoes but the chief consideration was to ascertain if there was any evidence of late blight. Although no actual figures were recorded, the yield was excellent and the tubers produced averaged 4-I6 ounces in weight. A close inspection of all individual plants failed to reveal any evidence of late blight at any time and it is now intended to plant about sixty tons from the crop in the regular potato area under government control and certification. The rest will be distributed between the operators in each of the producing districts.

Without the necessary isolation from their virus-affected varie- ties, and v~ithout properly trained help for roguing, it is doubtful if the im~ported seed can be maintained to certification standards for very long and it is probable that further importations will be necessary from time to time in the future. The names of some of the common

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native varieties in production there are the Corahila Quelguico, C. Chonchi, C. Rilan, C. Chelin, C. Chaulinec, C. Mechaico, C. Tangui, C. Rauco, C. Alao, Rosada Pudeto, Blanca Alemann, Pudeto, Huevo

ARGENTINA : - -The information collected on the problems in Argentina would suffice for a volume. However, it is hoped that some idea of the situation there may be secured from a few paragraphs under this heading.

After several potato crop failures or near failures, it was realized that diseases in the local varieties were playing a more prominent part in these failures than were weather conditions, and in the fall of 1936 the Government there sponsored large importations of certified seed from North America. The project was so successful that dealers were allowed to import upwards of two million bushels of certified seed from North America and several European countries in 1937 . The principal varieties imported were Green Mountain, and Katahdin from North America and a total of fifty additional varieties from Europe. A system of seed potato certification similar to that in effect in North America has been adopted in the hope of maintaining suf- ficient good seed to meet the requirements of the country, but it would appear doubtful if this can be done, not for a few years at any rate, and the fact that large quantities of seed have been imported this fall in spite of a surplus production of table stock from last year 's impor- tations of seed, would seem to bear this out. The enormous number of volunteer potato plants observed, most of which were affected with either leaf roll or mosaic, would indicate that virus diseases are likely to remain a serious problem in that country.

Considerable alarm was expressed in some areas there this spring over the appearance of a form of breakdown to which had been given the name of "Wil t" by the dealers and growers, and capital was being made by some dealers in announcing that this was found only in Green Mountain and Katahdin potatoes. At work in an adjacent country at the time, the opportunity was afforded the writer to inves- tigate the trouble in several large field in districts where most of the imported seed had been planted early. The principal trouble was re- ported to be a wilting of the tops, accompanied with a breakdown of tubers w~hich was referred to locally as chocolata.

At the first glance over a field one would likely conclude that there had been a light frost a few days previously, sufficient to nip the tops here and there throughout the field. On individual plants it appeared to be a form of die-back of the terminal shoots -for about six inches or so- In most cases there was a heavy infestation of early blight on the

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leaves of that portion of the plant which had died, and additional numerous similar dark spots which were not caused by early blight. A discoloration appears in broken lines in the epidermis of the stem somewhat resembling streak, but there was no discoloration of the veins of the leaves in evidence as in streak. In one field examined, about one plant in every tw,o affected this way had internal rust spots in the pith of the stems and in some tubers, somewhat resembling yel- low dwarf, and on approximately one affected plant in four were found tubers w'hich had turned a dark brown color both externallv and internally, starting at the seed end and tracing back for one inch or more. Having had an opportunity during the past twenty years of seeing or hearing something about all the potato diseases present on the North American continent and never having seen these troubles before, and furthermore, as the same troubles were found in varying percentages in every variety from every source, it was concluded that they were most probably of local origin. I t was disclosed later that choeolata has been known to the growers there for some years. Whether or not there is any correlation between the two diseases was not definitely established. They are now being thoroughly investi- gated by the local sanitary authorities. The same troubles were later seen in both Uruguay and Brazil and in the latter country Dr. Costa, working with a disease of tobacco which he had named Vira Cabeca, but which he was of the opinion might be Spotted Wilt, expressed the opinion that this potato trouble might be the same disease and had been transmitted to potatoes by thrips. Later it was ascertained that a similar disease of tobacco had been reported in Argentina in I93I under the name of De Corcoro. Thrips are abundant in many potato fields in Argentina. I t must be left to the future to determine the con- nection, if any.

Reference to Argentina would be incomplete without some men-. tion of the high standard and yields of potatoes produced under irri- gation from North American seed in the Mendoza and Rio Negra inland districts. Their fine pack of well-graded, clean, bright, uni- form potatoes would he a credit to any country. All potatoes are marketed through the National Potato Exchange in Buenos Aires and frequently there are Ioo,ooo bushels or more on hand there.

URUGUAY : - -Th is country now has a well-established certification service. Formerly they imported most of their seed from the Balcarce district in Argentina, but now secure the bulk of their seed imports from North America and other countries. They seem to favor Katah- dins from North America and other varieties from Germany. Appar-

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ently some of them can be maintained to a fair standard for two or three years. The question of foreign exchange apparently determines the quantity that may be imported into that country.

BRAZIL :--Imports of seed potatoes amount to about IOO,OOO crates annually, mostly from Germany and Holland, though formerly con- siderable quantities were imported from Argentina. Varieties must be recommended by the Experiment Station at Campinas before imports are allowed. Only potatoes with yellow flesh are under test at present and apparently the Eigenheimer from Holland is giving best results. One grower was most enthusiastic over smooth Burbanks imported some years ago from Canada and wants more. There appears to be no reason to suspect that North American seed would not give excellent results there, or that white flesh potatoes would not soon find favor. The question of foreign exchange apparently has some bearing on the present preference for seed from some European countries. Potatoes are grown in the mountains similar to the plan followed in other tropical countries.

In conclusion, it is evident that potato production problems in South America are many and varied and that the seed industry there has not reached the standard with which we are familiar in North America. With poor equipment the cost of production is high in most countries there, despite the low standard of living for the potato grow- ers, and the favorable climatic conditions in some areas. Increased appropriations for scientific work on seed potato problems would un- doubtedly lead to considerable improvement in the industry there.

SECTIONAL NOTES

CALIFORNIA

In Kern County a real Potato Pro-Rate is in effect at present. No potatoes are shipped--even within the state, that do not grade 8o per cent U. S. No. I or better.

The Pro-Rate is worked in this manner: First, the grower leaves all definitely undesirable potatoes on the ground; the rest are picked up and brought to the loading sheds in half sacks. They are then graded to either U. S. No. I or Commercial Grade, depend- ing on their quality.

It is variously estimated that between the potatoes left on the ground and those that are thrown out in the sorting, there is a loss of approximately 20-30 per cent, but even so the net yield at this time will probably be about 200 sacks of potatoes to the acre.