H.—34

PRTJIT COT/D STORAGE RESEARCH Advisory Committee). —Mr. W. K. Dallas (Chairman), Sir Theodore Rigs', Messrs. H. G. Apsey, W. Benzies, F. R. Callaghan, J. T. Cross, F. W. Grainger, H. C. Heays, J. L. Mandeno, A. Powell, A. M. Robertson, H. E. Stephens, L. W. Tiller (Secretary). Refrigerated Gas Storage of Apples Owing to staff shortage the detailed work begun on the gas storage of the Granny Smith in the small-scale experimental store in 1941 by the Dominion Laboratory could not be followed up in the season under review, and attention, was concentrated more on the semicommercial scale gas storage of Jonathan and Sturmer. Since, however, superficial scald had been troublesome in the previous year's gas-storage tests on Granny Smith, a detailed study is being undertaken in ordinary refrigerated storage to obtain more fundamental knowledge regarding the time of appearance of .scald in storage and on the effect of delayed storage. Progress notes on this work are given in the next section. Jonathan..—This season the fruit was not received till nearly three weeks later than in the previous year, and was of advanced maturity. The carbon-dioxide content of the storage atmosphere was maintained at 8 per cent., as this had proved the optimum in previous years' work, but it was found that severe brown-heart developed during the first eight weeks of storage and that every fruit was affected to a greater or lesser extent It is evident that maturity of fruit at harvesting is a factor of vital significance in the successful gas storage of the Jonathan. Sturmer.—Tn 1941, trouble akin to brown-heart was experienced in this variety and was attributed entirely to an escape of refrigerant from a leak, in the evaporator. The defect was located and repaired, but nevertheless a disorder of similar appearance has been encountered in the fruit again this season, although it has been very much less in amount. It appears to be brown-heart, and this suggests that some undetermined factors are preventing the successful results obtained in previous seasons' small-scale tests from being duplicated in large-scale trials. Further detailed study of the Sturmer variety is obviously demanded, and this is to be put in hand in the 1943 season. Superficial Scald on Granny Smith Wrapping Test. —Two sets of fruit were observed, one in which the apples were wrapped in oiled paper at various stages in their storage life and the other in which they were left unwrapped for a similar short period. The test was conducted on fruit at two stages of maturity, and the length of the period during which any one lot of fruit had its special wrap or no-wrap treatment was three weeks. It is of interest to note that none of the fruit that was unwrapped for only a three-week period developed scald. The other scries, however, indicated that the period of maximum scald susceptibility was between the ninth and twelfth weeks of storage. Belayed Storage Test.—Fruit of two pickings was stored in both plain and oiled wraps, and for comparison with the immediately-stored fruit other lots were held at room temperature for periods of one to four weeks before storing. Oiled wraps delayed the appearance of scald by eight weeks in the first-pick fruit and by eleven weeks in the second-pick fruit. As regards the effect of delayed storage on development of scald, the results indicate that, irrespective of date of picking or wrappers used, scald is at a minimum if the fruit is either stored immediately or else delayed for not less than four weeks. Willi any period of delay less than a month, scald is increased. Long-delayed storage, however, is accompanied by very undesirable effects on maturity and on incidence of fungus, so the work suggests the use of oiled wraps, immediate storage, and avoidance of early picking as the best means of achieving success in cold storing the Granny Smith variety. Effect of Fertilizers on Cold-storage Quality Observations have been maintained on the storage quality of fruit from the manurial blocks at the Appleby Research Orchard. Cox's Orange Pippin.—Nitrogen has again greatly increased susceptibility to breakdown and fungus, and reduced somewhat the incidence of wilt, PK without N has given less breakdown and fungus, but more wilt, than the untreated control. The complete PNK treatment has this season given fruit showing as good storage quality as the control fruit. Both pit and superficial scald have been less severe in later picks than in earlier ones. No difference in keeping-quality could be. detected between fruit from trees receiving ammonium sulphate and from trees receiving dried blood. Dunn's Favourite. —A heavy application of 41b. ammonium sulphate additional to normal dressings of P and K increased both breakdown and fungus, but this season the 21b. dressing gave results almost identical with those of the controls that had no nitrogen. N unbalanced by P and K again caused a big increase in superficial scald, but the inclusion of P and K did much toward correcting this. Jonathan. —As has been usual in the "off year" crops, applications of 21b. and 41b. ammonium sulphate have caused progressive increases in the incidence of breakdown, but only the heavier application has increased the amount of fungus. Potash has again reduced the incidence of breakdown and fungus, especially in late-picked fruit, and has caused only a slight increase in the amount of Jonathan-spot. Delicious.—The storage quality of this variety continues to be unaffected by manurial treatments. Sturmer.—N, unbalanced by P and K, has .greatly increased both breakdown and fungus, but substantially reduced wilt. The PNK fruit has had no more breakdown and fungus, and only a little more wilt and superficial scald, than the untreated fruit. Phosphate alone has reduced breakdown susceptibility.

7