W. J. Hooker ............................................ President P. J. Eastman ...................................... President-elect O. C. Turnquist .................................. Vice-President N. M. Parks .................... I.mmediate Past President J. C. Campbell ............................................ Treasurer R. V. Akeley ................................................ Secretary E. J. Wheeler ................................................ Director D. S. McLachlan .......................................... Director C. E. Cunningham ........................................ Director

Two methods are derived for estimating measures of pass-fail reliability. The methods require only a sin gle test administration and are computationally simple. Both are based on the Spearman-Brown formula for estimating stepped-up reliability. The non-distribu tional method requires only that the test be divisible into parallel half-tests; the normal method makes the additional assumption of normally distributed test scores. Bias for the two procedures is investigated by simulation. For nearly normal test score distributions, the normal method performed slightly better than the non-distributional method, but for moderately to se verely skewed or symmetric platykurtic test score dis tributions the non-distributional method was superior. Test results from a licensure examination are used to illustrate the methods. Index terms: Cohen's kappa, licensure examinations, pass-fail reliability, reliability, Spearman-Brown formula.

Everyone involved in international development work should have one mandate, to work themselves out of a job, as soon as possible. Seldom in government institutions or private industry does a person say, “I am needed no more”. Already one person has said this within the Potato Program and has been sent home. Two more have said they will no longer be needed at the close of their present contract. The reasons have been properly documentated and it is an indication of the progress which has taken place in the National Potato Program of Peru in a relatively short time.

Seed potatoes of the Katahdin, Kennebec, and Pungo varieties were treated with Fusarex dust containing 6% tetrachloronitrobenzene at three dates in Maine during 1961–62 storage season. In 1962, these chemically treated seed potatoes were planted in uniform tests and compared with seed stocks that had been desprouted once and also with untreated seed tubers. Cooperators in Maine, Long Island, and New Jersey, Pennsylvania, and New Brunswick, Canada recorded plant emergence and yield data at each location.

The 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.

Internal sprouting had been a problem in commercial storages with chipping potatoes prior to the use of CIPC.

Losses of ammonia from application of anhydrous ammonia were negligible when applied at a rate of 100 pounds N per acre and injected 4 inches or more below the surface.

The decyl alcohol gave effective sprout inhibition at a dosage of 1.9 ml per bushel. Lenticel pitting was observed when dosage was applied in less than three days. Application was by dripping onto a hot plate and recirculating vapors through the storage pile.

Considerable yield differences were found among certified Katahdin seed sources. Some of this variability may be due to virus X and some due to cultural and storage practices. The amount of variability deviates from year to year. These differences in yield among sources might possibly be minimized through cultural and storage techniques in the seed-producing areas.

Commercial control of sprouting, for long terms, can be obtained with most important potato varieties with irradiation dosages of 7,500 to 12,500r depending on the variety. There is considerable variation among varieties.

Research 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.