A study of the factors influencing the improvement of the potato / by Edward M. East.

  • East, Edward M. (Edward Murray), 1879-1938.
Date:
1908
Catalogue details

Licence: In copyright

Credit: A study of the factors influencing the improvement of the potato / by Edward M. East. Source: Wellcome Collection.

    22/88
    in the origination of new types. But, even if artificially produced fluctuations were heritable, there would be no necessity for their production; for, owing to the hybrid character of the greater number of potato varieties—or for other reasons—the natural variation of seedlings is very great, even when they are the product of crosses within the variety. Foreign varieties may very properly be grown until they are fully acclimated; that is, until the varie- ties are growing with full vigor. During the first year or two such varieties seldom flower; and even if they do, the flowers fall more quickly than they do with vigorous plants, and hybridization is ef- fected with difficulty. There is also some doubt as to the value of bud variations, but pending further investigations, we should watch for any such oc- currences. Data soon to be published by the writer seem to indicate that progressive mutations, that is, the appearance of an entirely new character, rarely and possibly never, occur. Bud variations are in nearly all cases merely the loss of a dominant character leav- ing the recessive allelomorph to appear. Such variations are not likely to be of great economic value. The selection of individual plants to be crossed is still a matter of personal opinion and experiment. While we may not believe in the heritability of vigor occurring as a fluctuation within a variety; still the greater ease of making crosses between vigorous plants is a sufficient reason for their selection as mother plants. The latter is due to the greater probability of their retaining the seed ball to its maturity. Girard selected plants having the most luxuriant vegetation, and according to T. A. Scarlett (88), the same method is practiced in Scotland. We have found that there is a great difference in varieties, as regards the value of luxuriant vegetation as a guide in selecting high yielding plants. Large vines versus medium vines gave fair results in most cases; but in some varieties as Manistee, large vines rather indicated that excessive vegetative growth was opposed to maximum tuber formation. Table 2. Selection of High Yielding Plants by Size Variety. Averag'e vine production in ounces. No. counted of each. Largfe vines. Medium vines. Pink Gem 21.5 14.25 50 Sir Walter Raleijrh 24.1 19.3 50 r'.arman N^o. ^ 22.1 20.0 10 Ti'.arly Ohio 16.0 16.1 10 I^,ar1y TVTani«tep. 16.6 16.9 10