SEED POTATOES

Hawke's Bay Tribune, Volume XXVI, Issue 143, 2 June 1936, Page 11

SEED POTATOES

Experimenting in New Zealand INCREASED YIELD The pre-treatment of seed potatoes by means of continuous illumination as a means of higher production has yet to be the subject of further experimenting in New Zealand in order to ascertain if the reports from Europe of increased yields will apply hero. Preliminary experiments were conducted at Palmerston North last season with Sutton Supreme, which is the leading variety for yield used in Hawke’s Bay. The results did not yield 'any marked advantageous effect either as a means of hastening maturity or increasing yield. This is not regarded as the final verdict for the treatment, as next season a more regulated cxperinqpit under more reperesentative conditions will be conducted.

Several years ago it was announced from Northern Europe that a new and very . successful method had been evolved for the treatment of seed potatoes, writes E.M.O. in the New Zealand ‘‘Herald.” It was claimed that when the tubers were kept in continuous illumination, during both day and night, tor twenty to thirty days before planting, the yield of potatoes was appreciably increased, and also the maturity of the crop was hastened by ten to twelve days. It was realised that if these claims could be substantiated under local conditions, the method would bo of considerable value to growers, especially in districts where potatoes are produced for the early market. Accordingly, during the last season, a simple preliminary experiment was conducted at Palmerston North, with the object of discovering how tar the treatment was effective.

A uniform sample of a certified strain cf Sutton Supreme seed potatoes was obtained, and divided into several equal lots. The tubers of one lot—group A—were, threaded Upon a length of thin wire, and suspended from the roof of a glasshouse at a distance of about 18 inches from a powerful electric light, which was turned on every night. The tubers of another lot—group B —were left in the glasshouse, hut were covered to keep out all light. To add further interest to the experiment, the tubers of a third lot —group C —were put eye-end upward in a shallow box, which was placed in a shaded position in the open. Thus, of the three groups of equal number and weight, A received continuous illumination, B was the control, receiving continuous darkness, and C received tho natural conditions of alternative day and night.

NO BENEFICIAL RESULTS. The treatments werg maintained for 30 days, at the end of whiofr period the tubers were planted wholo in tho Held. Under all three different conditions of light the seed had sprouted abundantly, but tho shoots in groups A and C were short, stout and very green, while those in group 13, having developed in tho dark, ware longer and very pale. Care wag taken not to damage any shoots in planting and no artificial fertilisers were applied to the plots. From this stage, no significant difference was observed in the grow th of the plants. All emerged from the soil at about tlw same time, the rate of growth subsequently appeared to be identical in all cases, and no difference was observed in flowering dates. In all three groups the tops died down at approximately the same time. That is to say, the treatment with continuous light did not apparently have any appreciable effect in hastening development toward maturity.

The crop was dug after maturity, and the respective yields measured. The plants of group A produced a total yield of 74.ti1b., aud tho same number of plants u groups B and U produced respectively 71.11 b and 85.41 b.; that is, the first or treated group showed an increased production of 3.51 b, or 5 per cent, over tho untreated or control group B. This increase, however, is not regarded as significant, and may easily have been due to some natural soil fertility factor that had not been taken into account. Thus, the result of The experiment was negative—its value has been to demonstrate that for the Sutton Supreme variety, and under the particular soil and elimato conditions of the trial the pre-treatment of seed potatoes with continuous illumination, as applied, has no advantageous effect either as a means of hastening maturity or of increasing yield. The most interesting part of the trial is the outstanding increase in yield obtained from Group O, this amounting to 20 per cent, over the control group B- The pre-treatment given to the seed of group C —namely, natural conditions of Tight and darkness in the open—is actually the method of sprouting recommended by the Department 'f Agriculture. There are still farmers and others growing domestic supplies of potatoes, however, who consider it sufficient to plant the seed straight from the darkness of the pit or sack. I’he experiment conduced serves to illustrate again the advantage of sprouting the teed tubers for a month or more in shallow boxes in the open, say, under the shelter of a tree, as an aid in producing the highest yields.

REBUTS IN RUSSIA. Tho failure of tho continuous light treatment to produce the effects claimed lor it seems to require some qualification, especially whcli tho method has given almost spectacular results in Europe. For instance, published records stale that iu 11134 the application of this treatment in Russia brought about an increased tuber yield of from 100 per cent, to 150 per cent, and accelerated maturity by one month. It must be remembered, in the first place, that the soil and climatic conditions of the particular region may have an Influence upon the result, and also that different varieties of potatoes may require slightly different conditions ol treatment. The actual technique of the treatment is perhaps a more important consideration. The temperature of the glasshouse, not being subject to control, rose and 101 l to extremes considerably beyond the limit.* observed overseas; aud, moreover, it has since been shown that the threading of tubers un wire, by breaking open the tissues, renders them mere susceptible to rotting, which naturally reacts disadvantageously on yield and growth, hi Europe the seed tubers are now treated with light while simply arranged in layers, although the method of threading was at first recommended, and was still in vogue when this trial was planned. V 'Hi these eonsldoralions in mind, it would seem that the results obtained as described above, must not yet he regarded as the final verdict for the

treatment in this ountry If is hoped that next seiisun another and better regulated experiment may be conducted under more i'iqirrs<m,ilire Conditions, nm] that ll'i will « n.-ibk ii definite answer |u Im aiven rjwrninjr Hie value of eotitiniloiis i'iiiniilfiition us n pie’ treatment ol seed potatoes.