MASSEY AGRICULTURAL COLLEGE

Manawatu Standard, Volume LII, Issue 306, 24 November 1932, Page 9

MASSEY AGRICULTURAL COLLEGE

MONTHLY BULLETIN. SEED COLOUR IN CRESTED DOGSTAIL. (By W. A. Jacques, B.Sc., N.D.A.) Recent work on crested dogstail at Massey Agricultural Collego has thrown light on to the question of colour in the seed, and it is thought that some of tho results may also be applicable to seeds of other grasses. Until recently farmers both here and in Groat Britain have demanded seed of a bright yellow colour and have neglected the darker samples. For New Zealand conditions this bright seed appeared satisfactory, as the germination was high. When exported to Great Britain, however, it was found that it lost a portion of its germination capacity en route, and in some cases this loss was considerable. It was found that samples of darker colour could withstand shipment better than the seed of a lighter colour, and this in itself suggests a greater vitality and a more perfeet stato of maturity, and the results of the trials confirm this opinion.

In crested dogstail that is harvested normally and stored rationally seed colour can be regarded as an indication of the maturity or ripeness of the grain. As the maturity progresses the green colour gives place to greenish yellow and then to colours darker than yellow, and tho final colour so attained varies with the different plants. Some plants produce seed which never be comes darker than orange brown; others produce seed which is almost black; while between these two there are many intermediate colour stages.

RELATION OF COLOUR TO GERMINATION, CAPACITY AND VITALITY.

When seeds are tested at the official Seed Testing Station at Palmerston North a certificate is issued showing the percentage of seeds which germinate in eight and IS days. The 18-day figures represent tho final count- in tho germination test and are quoted by the seedsmen when giving the germination capacity of that particular line. In practically all cases the golden yellow samples give a high figure, and for New Zealand conditions at least appear satisfactory. It is only after a consideration of tho eight-day figures that their weakness is apparent. The interim (eight-day) count shows that actually such seeds are immature and have a much lower vitality than seeds which have developed sufficiently to attain tho brown colour. This in itself may not bo a serious drawback under New Zealand conditions, but this lack of vitality is one of the causes which are undermining the demand for New Zealand seed abroad. It is fortunate for Now Zealand that Ireland, her main

competitor in the English market, has a poor climate for seed production and frequently has only unattractive samples to offer. In a current year’s seed catalogue sent out from England New Zealand dogstail seed is offered at the same price as Irish seed (1/3), hut tho germination figure is 10 per cent, lower than the Irish seed. This in itself is sufficient to reduce the demand for the New Zealand seed. It thus devolves on the Dominion growers to produce an attractive sample which has the requisite high germination capacity. This can only bo attained by allowing tho seed to become more mature. The crops should bo cut at a stage which will give a light brown seed sample; this will still be attractive and pleasing rn appearance, and what is more, it will be an excellent product.

THE RELATION OF COLOUR TO SEED WEIGHT.

As colour deepens, so does the indivi

dual seed weight increase. It was found that brown seeds were 20 to 33 per cent, heavier than the canary yellow seeds from the same plant. This not only indicates a better filled seed, but also a greater food reserve, which will enable the dogstail. to better withstand early competition in tho pasture. To some extent it compensates for tho loss which occurs from shedding due to allowing the crop to stand longer before being cut. When everything is considered the balance is very much in favour of the darker seed, providing it has been well stored. Where "stripped” seed has been allowed to heat, frequently extremely dark samples result, and these naturally should be regarded with suspicion. The critical test is vitality and germination, and these should be considered before any other factor. It is not intended to convey the impression that with the purchase and

use of the best seed all dogstail problems are solved, but it does mean that by so doing the best results can bo expected from the material that is at present in commerce, and that the Home samples of New Zealand seed will at least compare favourably with those produced in Ireland.