GROWING POTATOES.

North Otago Times, Volume CVII, Issue 17167, 25 March 1927, Page 3

GROWING POTATOES.

CERTIFICATION OF SEF.D. The Fields Division of the Department of Agriculture has docided to co-operate with grower's in the certification of purcr and healthy c.rops of potatoes for seed purposes. It recognises that there is a "demand both by growers and by merchants for reliable and dependable seed. and that the producer should reap a fuller reward for his painstaking care in its production. Potato varieties in New Zealand hafe become so mixed that it is almost impossihle to purchase pure I lines unless the variety has some | distinguishing characteristic. To j some extent the grower is not obtaining the best result attainable, when he used mixed seed, and the merchants and seedsmen having in most pases very little knowledge regarding the lines offered them must necessarily purchase warily without the confidence they should have. One result of certification, ' therefore, will be an assurance to the purchaser of certified seed that the crop has been examined and has ! passed a certain standard in respect j to varietal purity. ! The position in, regard to potato diseases in New Zealand is as serius as it is in other countries where certification has been the means of greatly reducing losses. By far the most important consideration in such a steheme is to give an impetus to the distribution of healthy seed. It is a well-known fact that the potato tends to degenerate or "run- i out" in certain localities. This, gen- : erally, is assumed to be directly ! connected with climatic conditions, | but such is probably not the case except in so far as climatic conditions affect the presence or absence of more or less definite diseases except that the yare transmitted ^ln the field, and also by the use - bf tubers from diseased plants, and that they exert a tremendous influence upon the yield of marketable tubers. In Canada it has been shown.lhat the average yield over a series of years from ordinary seed is four tons, and that from certified seed seven tons per acre. Certification has, of course, been carried out for a considerable number of years in this country. The department has grown this year at the Ashburton Experimental Farm a very large number of small lots of four standard varieties colleeted from all over the South Is!and. Some are normal, healthy strains and a few are particularly productive. Quite a number, however, liave dege.nerat.ed to a great extent, as to render them cxtremely unproductive and totally unfit for ceed purposes. So inarked are the differences that it is obviously Ihe dcty of the department to arrange ; so i'ar as it is able, the wider distribution of the better and isealthialr '•v'us of uiu- standard varieties. There are other diseases prevaS- j cn' throughout Canterhury, notably. ' Co.l cium. Probably no .crop in ih"

province is free from this disease, ^>ut it is more severe in some cases tthan in others ,and herein lies the possibility of increasing production by the distribution of the healthier tubers. Mattery Eye, Powder> Scab Eelworm, Early and Late Blight all play their pa.rt in reducing production and are transmitted in or on the tubers used for seed. The Fields Division, therefore, undertakes to inspect any crop next season which . the grower thinks is of a reasonably high standard in respect to purity and health, and is prepared to inspect with a view to certification one acre or-more of any one of the following varieties: Arran Chief, Breezes Prolific, Up to Date, No'rthern Star, Gamekeeper, King Edward Endurance, Ancklander, Sutton's Supreme, Dakotas, Robin Adair, Early Regent, Magnum Bonum, Early Rose, Pink Beauty of Hebron White Beauty of Hebron, Britisb Queen, Early Puritan. While the Department is not prepared to carry out inspections and certifications till the season 1927-28, it is prepared to give the fullest assistance to growers this season, and may arrange a visit from one of its oflicers where time permits. Growers will be advised later of all details in regard to certification, and it is sufficient to say at present that the fullest publicity will be given in regard to growers whose potatoes become certified and registered. This early announcement of the scheme is aimed at, allowing growers sufficient notice so that they may if they wish, take steps this season to produce selected seed for the planting of such areas as they desire next year to have certified. Some growers have been very successful in the improvement of their strains. The department re- . cognises that there exists great diversity of opinion as to the best means to this end, and considers that it is advisable for each grower to adopt such means as he thinks best. Generally speaking, however, the following methods are conimonly practised: — 1. By going th rough the crop and digging normal healthy shaws the tubers of which are retained if vield and iype is aaao satifsactoFiv The tubers so produce^ are cut small ones being discarded) and nTanted ira a "seed plct" or "increase plot" of a siso to nrcducc seed for ae .o op ihe folL