284 
JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 
mechanical condition is, nor what manures one may apply, or in what 
quantities. 
Now there are a few points connected with seed well worth con- 
sidering :— 
(a) New varieties generally do much better than old varieties : they 
are stronger in growth, producing broader leaves and thicker haulms; 
they are less liable to be attacked by disease, and better able to withstand 
frost. But as these new varieties become older they are almost certain to 
degenerate. The reason is quite simple. A potato multiplies in two 
ways: (1) By seed, or sexually ; (2) by tubers, or asexually ; and the latter 
way is the more common method by which the potato crop is reproduced. 
Professor Johnson says * " that it is a generally accepted principle in 
"biology that the possession of sexuality is a sign of vigour ; that a plant 
possessing male and female organs, which results in the production of 
fruit and seeds, is more likely to maintain its tone than a plant which 
has no fruit or seeds and reproduces itself vegetatively." This is the case 
with the potato ; and the cause of rapid degeneration in many varieties 
can be explained by this repeated vegetative reproduction, that is, by 
means of tubers. We have frequently noticed that the variety which has 
no sexual organs or produces no flowers is much more likely to degenerate 
rapidly than those which produce flowers or those of more vigorous 
growth. 
By hybridising or crossing two varieties we introduce new varieties : 
these are more vigorous, owing to the introduction of new protoplasm. 
New varieties cannot be raised vegetatively, that is, by tubers. 
{h) It is very important that the seed should come from a more 
northerly district or from a colder climate, because a plant brought from 
a cold region to a milder or warmer climate will be more vigorous in 
growth, hardier, and better able to withstand frost and disease than those 
brought from a warmer climate. But from experiments carried out at 
Holmes Chapel we find that seed potatos brought from Scotland are from 
ten to fourteen days later in sprouting and ripening than seed from the 
South of England ; therefore we should say, if a grower wants to have 
potatos earlier than those of his own district, he should go south for seed, 
but if a heavy crop is wanted and early maturity is of no importance, one 
should certainly procure seed from the north. 
{c) The soil on which the seed has been grown is another point 
worthy of attention. The seed should be procured from soil as different as 
possible in composition and texture from that upon which it is intended 
to plant the tubers. If the soil is sandy, we would procure the seed from 
heavy clay land, from peat or alluvial soils ; if, on the other hand, the soil 
is heavy, the seed should be procured from sandy land or from peat. The 
greater the difference in soils, the better will the results be. 
{d) The size of seed or tubers planted influences the crop to a 
wonderful extent ; but we intend to refer to this point later on. 
(c) The tubers selected must be sound, free from all traces of disease ; 
those varieties must be chosen which are the best disease resisters, with 
shallow eyes, rough skin, and white in flesh and skin, as these take best 
in the market, also those which form a good soapy lather when cut in 
♦ See Beport of the Conference and Exhibition of the Tercentenary of the Potato. 
