Plant-breeding; comments on the experiments of Nilsson and Burbank . and treatment than the localvarieties. It is, however, unavoidable that, with the strawof the manure, some stray grains of these inferior sorts will,from time to time, and not rarely, come onto the fields. Herethey will be content with a lesser supply of food, space andcare than the improved races, and thereby be enabled to growfaster and multiply more ciuickly. It is hardly conceivablehow soon these inferior races may multiply themselves to suchan extent as to occupy large parts of the field, supplantingthe ameHorated type a
Plant-breeding; comments on the experiments of Nilsson and Burbank . and treatment than the localvarieties. It is, however, unavoidable that, with the strawof the manure, some stray grains of these inferior sorts will,from time to time, and not rarely, come onto the fields. Herethey will be content with a lesser supply of food, space andcare than the improved races, and thereby be enabled to growfaster and multiply more ciuickly. It is hardly conceivablehow soon these inferior races may multiply themselves to suchan extent as to occupy large parts of the field, supplantingthe ameHorated type and lessening the harvest to a noticeabledegree. In bad years, even the wind oats which scattertheir small seeds to the winds and thereby yield nothing atall for the harvest, may be seen to replace more than half thestock of the fields Under such circumstances, keeping the races pure bymeans of selection is evidently a necessary part of all intelli-gent culture. It is the first thing to be done, but it is consid-ered hardly worthy the name of imi)rovement. In Ger-. 57 58 PLANT-BREEDING many, real improvement was treated as a separate occupationand was considered as requiring a large amount of study,and the devoting of oneself to a proposed aim. The gener-al custom was to start such experiments from the best localor improved varieties by an initial choice of a certain numberof typical heads. Such a group of selected plants wascalled the elite, and this elite had to be ameliorated accord-ing to the prevaiHng demands or even simply in accordancewith some ideal model. Year after year, the best ears ofthe ehte group were chosen for the continuance of the strainor family, and slowly, but gradually, its quahties were seento improve in the desired direction. After some years,such a family might become decidedly better than the varietyfrom which it had been derived. Then its yearly harvestwould be divided into two parts, after having been sufticientlypurified ])y the rejection of acciden
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