SEED-TESTING NOTES.

New Zealand Journal of Agriculture, Volume XVII, Issue 2, 20 August 1918, Page 95

SEED-TESTING NOTES.

By

E. BRUCE LEVY,

Biological Laboratory

In view of the restrictions on export from Britain it is highly probable that all available stocks of turnip, swede, and rape seed at present in store in New Zealand will be drawn upon for the 1918 and 1919 sowings.- Importations are still arriving, but there is no doubt that much old stock will of necessity be put into use. The following table of germination-analyses, compiled from a consideration of 418 samples tested from April to July, gives a good indication of the germination capacity of the lines of turnip, swede, rape, and kale seed at present in store in the Dominion :-

■ The great necessity for the farmer to know the germination of the seed he is sowing will be obvious from an examination of this table. With low-germinating lines, even if sown thickly, the danger of failure

is great, for the vitality even of those seeds which do germinate is low, and consequently establishment of the plants is uncertain. The merchant will be loath to sell his client 'seed of low vitality, but if it comes to the worst and supplies are really short, then something must be done so that the low-germinating lines can be utilized with the least harm to the general turnip crops of the country. To mix highgerminating with low-germinating lines seems the most feasible thing to do. This would be preferable to selling each line separately, even if the germination certificate accompanied the seed sold. If even, say, 50 per cent, of a real good germinating (90-100 per cent) seed be included in a poor-germinating line the resultant take should be quite good. In the writer’s opinion this would be the best course for merchants to adopt, even if. it be, necessary for them to buy highgerminating seed at a fairly high price. It will be obvious, of course, that the mixing should be done only with lines of one variety Superlative ' swede with Superlative swede, for instance and with seed from the same European exporter only. Merchants should aim at as high a general germination as possible, and this should in no- case be less than 70 per cent. The following table suggests a method of mixing which, while the germination of the resultant mixture would be quite satisfactory, enables much of the poorer seed to be utilized . . .

Seed lower than 40 per cent, germination should not be used for such mixing.

It must be borne in mind that the mixing of lines as a general practice is not for a moment advocated for normal conditions, but special; conditions call for special actions, and if the shortage really becomes acute,. then by adoption of the above methods the farmer should be secured against crop failures due to unduly low-germinating seed, while at the same time a supply equal to the requirements of all would be more readily available. ’ The only other method to ensure reasonable security, for the farmer is for him to know the germination of the seed he sows, sb that in the case of a low-germinating line a corresponding increase in the amount could be. gauged and sown. Apart, however, from the factor of lowvitality seed, increasing the amount sown means a departure by the farmer, from. his usual procedure, and it is doubtful whether the exigencies of the moment would appear pressing enough for him to alter his established practice based bn normal experience..

Note. —The non-specified varieties of turnips are those in which the sender uses a distinguishing mark only. Included in these is a good number of garden varieties.

Turnips . Minimum. Average. Maximum Per Cent. Average. Per Cent. Maximum Per Cent. Green-top Yellow Aberdeen 16 72’7 ■ 99 Purple-top Yellow Aberdeen . . 46 79 99 Purple-top Mammoth . . • • 43 83-7 97 Devonshire Grey stone . . • • 39 75’3 98 Hardy Green Globe . . 29 57’25 93 Imperial Green Globe . . . . 12 87-7 99 Lincoln Red Globe • • 77 93’4 99 Forsterton Hybrid . . 68 90-75 99 Other varieties • • 30 70-6 94 Varieties, not specified . . . . 14 . 83-5 100 Swedes Magnum Bonum • • 3i 57 87 Champion . . . ■ . . . 12 73’7 94 Elephant .. ... 0 75 87 John 'Bull .. .. . . 40 75 93 Superlative 12 • 63-75 98 Crimson King. . ■ • 45 75’3 96 Other varieties • • 58 79 . 87 ■ -Varieties not specified . . 5 77’5 97 Rape— • Broad-leaf Essex . . 18 87 100 Kale— , ■ • Thousand-headed and Buda; 2 55'5 92

Seed to be mixed. Proportions of each to be mixed. . : Germination of • Resultant Mixture. 90% and 40% seed . . 70% of 90% seed with 30% of 40% seed ■ 75% 90% and 50% seed . . 60% of 90% seed with 40% of 50% seed 74%' . . . .90% and 60% seed . . 50% of each ... . .7 .. 75% • 90% and 70% seed . . 40% of 90% seed with 60% of 70% seed 78% Alternative if a Higher Standard- can be maintained. . 90% and 50% seed . . 80% of 90% seed with 20% of 50% seed . 82%. 90% and 60% seed . . 75% of 90% seed with 25% of 60% seed 82-5% 90% and 70% seed . . 70% of 90% seed with 30% of 70% seed ■■■■■■ 84% 90% and 80% seed . . . 55% of 90%. seed with 45% of 80% seed ■ 84-5% For the many Cases in which Lines of Higher Germination than 90% are available. which Lines of Higher .Germination than go% are available'. ■98% and 40% seed . . 60% of 98% seed with 40% of 40% seed ' ' 74-8%