Richard L. Sawyer

Relation of Chloro IPC for potato sprout inhibition to internal sprouting of potatoes

The potential of Chloro I P C for sprout inhibition of potatoes was discovered by Paul C. Marth of the U.S.D.A. Agricultural Research Service, Beltsville, Maryland. Marth and Schultz first published on this in 1952 and Heinze, Marth and Craft published on further tests in 1955. Early work indicated the strong inhibiting potential using either a dust or a dip. Inlpregnated paper was not effective except for tubers close to the paper. In general, the conclusions of Mir th and Heinze were that potatoes needed to be held at temperatures under 70 F immediately after treatnlent for a time to be effective; less rot was obtained with treated tubers at temperatures of 55 F or under, but more rot was obtained with treated tubers at 65 F. Chloro IPC was found effective as a dip, a spray, or incorporated in a wax enaulsion on potatoes by Heiligman and Wagner in 1957. Sprouting and weight loss were reduced at storage temperatures of 55 F, 72 F and 85 F and Chloro I P C seemed to have an indirect effect in controlling storage losses caused by microbial decay. A new method of application was reported by Sawyer and Dallyn in 1956 and 1957. Chloro I P C gave effective inhibition when applied as a gas to potatoes in storage. Volatizing by heating to 200 C gave better results than atomizing into the ventilating air. However, both methods gave good commercial control. Application details consisted of a ventilating system delivering .25 cubic feet of air per bushel of tubers. After application, storages were kept closed and the air recirculated for 24 to 48 hours, followed by normal ventilating procedures. Chloro I P C was applied after adequate healing of cuts and bruises from the harvesting and storing operation. Sawyer and Cetas in 1957 and 1958, working with 400-bushel experimental bins. found that Chloro IPC applied to well-cured potatoes in storage did not increase the amount of dry rot; however, the application to freshly harvested or poorly cured potatoes in storage could result in increased dry rot. Tubers treated with Chloro I P C and held at 50 F gave excellent control of shrinkage and black spot at a treatment dosage of gram per bushel. Hendel in 1957 reported on several considerations in using Chloro 1PC. Wound healing was greatly retarded by application of Chloro I P C to freshly cut surfaces and caused a loss of fluid and blackening of the surfaces: and air velocity was important in storage for uniform distribution. Hendel also found Chloro I P C to have a fungistatic effect on dry rot organisms. Sprouting of potatoes was effectively controlled at 50 F with 1 to 2 ppm on the tubers.

The effect of gamma irradiation on the incidence of black spot, and ascorbic acid, glutathione and tyrosinase content of potato tubers

ConclusionsResearch over a three year period demonstrated that gamma irradiation of potatoes results in increased black spot. Specific dosages necessary to initiate the increase cannot be given because of yearly and variety variations.Irradiation decreased ascorbic acid content, increased glutathione content and modified the tyrosinase content as the dry matter was affected.No specific cause and effect relationship could be demonstrated between black spot incidence and the content of ascorbic acid, glutathione or tyrosinase. High levels of ascorbic acid in the Green Mountain variety resulted in natural radio-resistance as measured by irradiation induced increases of black spot.

A study of the oxygen-periderm relationship in potato tubers and the effect of oxygen on the normal breaking of the rest period

A S T U D Y OF T H E O X Y G E N P E R I D E R M R E L A T I O N S H I P IN P O T A T O T U B E R S AND T H E E F F E C T O F O X Y G E N ON T H E N O R M A L B R E A K I N G OF T H E R E S T P E R I O D 1 RICHARD L. SAWYER AND ORA SMITH 2 Since Appleman in 1914 found an increased oxygen absorption was correlated with treatments which abbreviate the rest period, several workers, some of whom have been widely quoted, have tried to explain the rest period phenomenon in tubers as the result of oxygen permeability of the periderm. There has been a diversity of opinion as to just how oxygen affects the rest period or if oxygen per se has any effect on the rest period. The same results have been used in some cases for opposite conclusions. This investigation was conducted to clear up some of these opposing theories and conclusions and possibly give a clearer understanding of the rest period phenomenon. Appleman (1) suggested that the rest period of the potato depended on the resistance of the periderm to the entrance of oxygen. Under normal conditions the skin becomes snberized before the completion of some growth mechanism requiring oxygen. When a proper adjustment had been made between the bud tissue and external agents, chiefly oxygen, Appleman believed the rest period would be broken. Thornton (7) , (8) also explains the normal breaking of the rest period in terms of the permeability of the periderm to oxygen. However, he believed the internal oxygen supply is limited by the periderm as the tuber becomes older in storage with new layers of cells developing and the cell walls becoming thicker. Gradually the internal oxygen is limited to such an extent that the rest period is broken. Emilsson (4) found no relation between the thickness of the periderm and length of the rest period. Burton (2) indicated that the flesh of the tuber offered no serious resistance to slow oxygen diffusion and concluded that oxygen concentration per se plays Ilo part in the onset and termination of the rest period under ordinary conditions.

Nitrogen fertilization of potatoes

Summary1.Yield increases under irrigated Long Island conditions were obtained with applications up to 210 pounds of nitrogen per acre with Cobbler and Katahdin varieties.2.Nitrogen distribution had little effect on yield as long as vines were allowed to go to maturity.3.When less than 70 pounds of the total nitrogen was applied at planting, maturity was delayed.4.In general, the earlier the nitrogen was applied the higher was the specific gravity.5.The nitrogen sources gave similar responses in all determinations made.

Timing maleic hydrazide sprays to stage of plant development

SummaryMaleic hydrazide sprays, 3 pounds per acre, applied at blossom fall gave consistently good sprout control. Sprays at this stage of plant development gave good results to potatoes planted early or late in the season.Maleic hydrazide sprays had no effect on black spot or peeling discoloration. There was no consistent detrimental effect on chipping quality.Late date of planting tended to decrease sprouting and black spot but had no consistent effect on specific gravity.

Magnesium fertilization of potatoes on Long Island

SummaryThe 40 to 60 lb. level of magnesium oxide equivalent application in fertilizers appears adequate in maintaining soil levels at 50 to 60 lb magnesium, and in building up lower soil levels on Long Island. Supplying this magnesium as half water soluble and half non-water soluble is superior to having all in one form or the other. Pulverized serpentine, a new magnesium source, was as good as the 50/50 mixture at the recommended levels of MgO equivalent and showed no deleterious effects from high levels of application. There appears to be no reason, from the results of two years’ testing, why pulverized serpentine should not be used as another magnesium source if there are no compatibility problems in mixing and if it is economically competitive.ResumenEl nivel de 40 a 60 libras de aplicación de equivalente de óxido de magnesio parece adecuado para mantener el suelo a niveles de 50 a 60 libras de magnesio y para mejorar los niveles más bajos de suelo en Long Island. Si esta cantidad de magnesio es mitad soluble y mitad insoluble en agua es mejor que tenerlo todo soluble o insoluble. Serpentina pulverizada, una nueva fuente de magnesio, parece tan buena la 50/50 mezcla al nivel recomendado de MgO equivalente y no produce efecros dañinos cuando aplicada en demasía. Parece que no hay razón alguna, después de dos años de experimentar, para que serpentina pulverizada no llegue a ser una fuente de magnesio si no hay problemas de incompatibilidad y si es economicamente competitiva.

The Potato Association of America

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International Potato Center Symposium on Key Problems and Potentials for Greater use of the Potato in the Developing World

D. Present research status and potential for solving some priority potato problems of the tropics. 1. Increasing the nutritional quality and quantity of the potato 2. Late Blight resistance (Phytophthora infestc~ns) 3. Golden Nematode resistance (Heterodera rostochiensls) 4. Brown Rot (Pseudomonas solanacearum) 5. Cold resistance for the highland tropics 6. Virus resistance in varieties for the tropics

Committee reports Potato Association of America

and secretarial fees. Bill submitted of

Annual Business Meeting Potato Association of America Wednesday, August 31, 1960

79.00 for abstract and secretarial fees for setting up program. Voted to pay it. 1960] N E W S A N D R E V I E W S 3 9 5 Honorary Life Membership. It was suggested that Life Members wear their badges so people would know and recognize them. Unanimous agreement that next years considerations remain two tecehnical and one nontechnical workers. No one was in favor of renewing affiliation with AIBS at the present time. Seal--general agreement that the seal should be accepted but further work be done on a crest. RICHARD L. SAWYER, Secretary ANNUAL BUSINESS MEETING POTATO ASSOCIATION OF AMERICA Wednesday, August 31, 1960 Secretarys report by R. L. Sawyer. Report accepted. Motion made by Paul Mosher and seconded by Robert Akeley. Treasurers report by J. C. Campbell. Report accepted. Motion made by J. C. Campbell and seconded by D. Isleib. Auditing Committee report by D. Isleib. Report accepted. Motion made by W. Sparks and seconded by R. Hougas. Seal and Crest. Voted to accept seal. Motion made by Walter Sparks and seconded by J. Campbell. It was voted to further investigate a crest. Motion made by L. Dionne and seconded by W. Sparks. Standards Committee, A. Hawkins reporting. Resolved that the Potato Association of America request the assistance of the Regional Laboratories to provide a standardized method of determining specific gravity by weight in air and water and provide a conversion table for converting specific gravity to dry matter. The Potato Association of America to contact the Chairman of the Potato Advisory Committee advising of the need for a standardized procedure and conversion table. In the interim the committee recommends that the method of determining specific gravity and the conversion table used for converting to dry matter be stated with each report. Report accepted. Motion made by C. L. Fitch and seconded by J. Haddock. Handbook Committee report by R. Akeley. R. Akdey briefly discussed the recommendation that the handbook contain information which wonld bring up to date all phases of potato production annually. Committee chairmen are responsible for bringing each section up to date. This still leaves room for yearly accent on a given subject. Recommendation accepted. Motion made by W. Sparks and seconded by J. Haddock. Vote was 12 against 16 in favor. Next years meeting. Paul Eastman reported that a desire to go west and hold the meeting the last of July or early August had been expressed by a number of people. There is an invitation by H. Werner to meet at l.incoln, Nebraska on record. G. Rieman suggests the Executive Committee explore the possibility of going to New Jersey. W. Sparks suggested the Red River Valley be considered. Several folk spoke in favor of meeting with other groups and several spoke in favor of meeting by ourselves. L. Dionne moved that the Executive Committee explore the