SELECTION OF PLANT-BREEDING 



John Belling, Washington, D. C. 



FINAL selection of improved races 

 by mere inspection has become, 

 in most cases, more or less 

 discredited among plant -breeders. 

 The progeny test is now the main 

 reliance of the breeder, and actual 

 measurements are found to be usually 

 more trustworthy than ocular estimates. 

 Hence selection often includes some 

 kind of testing before the act of choice. 

 Without trial of some kind, selection 

 consists in picking out the best looking 

 individuals, in breeding for "fine 

 feathers" and not for performance. 

 This leads to pretty exhibits at the 

 agricultural shows and county fairs, 

 but does not cheapen the production 

 of food. It is usually simple enough 

 to pick out individuals which "look" 

 better than the biilk of the crop, but 

 to prove whether they are or are not 

 better is often a longer process. In 

 some cases the results of the progeny 

 tests mechanically determine the best 

 lines, with little or no personal selection 

 on the part of the operator. Thus in 

 improving Swedish wheat, Nilsson-Ehle 

 takes at random plants of the old native 

 wheat (which had already been shown 

 to be a mixture of lines) and tests their 

 progenies alongside for maximum crop, 

 etc. Even in the progeny of crosses 

 (e. g., potato) where the plants are 

 multiplied as clons (by scions, cuttings, 

 tubers, etc.), the testing of the likeliest 

 looking plants is often the hardest 

 part of the work. Selection of seed- 

 plants is carried on in two directions: 

 (1) to obtain superior lines and (2) to 

 breed them to constancy. The more 

 genetic variation we have, the more 

 material there is for selection. Bud 



selection, so far, has only scored notable 

 successes in a very few cases. Even in 

 potatoes most, if not all, of the recog- 

 nized market varieties originated in 

 crosses or seedlings. Crossing is the 

 recognized means of gaining material 

 for selection. It seems probable, for 

 example, that most, or all, of the many 

 strains of the common bean (Phaseolus) 

 and of the cowpea were selected from 

 natural or artificial crosses. The nur- 

 seryman's class of "sports" usually 

 inchides the products of natural crossing 

 by insects. In plants which are natur- 

 ally much crossed, as maize, a modified 

 mass selection must be practiced, be- 

 cause of the loss in productivity which 

 usually follows self-pollination or in- 

 breeding. But in predominantly selfed 

 crops, as beans and wheat, mass 

 selection is no longer used, but strict 

 individual pedigrees are kept. In such 

 cases, progress depends on never mixing 

 the seeds of bwo or more plants until 

 relative constancy is obtained. 



In all cases characters are selected 

 directly and plants indirectly, and all 

 knowledge gained in the progress of the 

 work, or previously, as to the mode of 

 inheritance of these characters, shortens 

 and cheapens the process. Thus, with 

 the increase of our knowledge which 

 is in large part due to American workers, 

 plant-breeding will be a more certain 

 and a less costly operation than in the 

 past. Even in the present, probably 

 many plant -breeders who have created 

 assured values for the community, 

 have lost money in the work. This 

 has been stated to be the case even with 

 Luther Burbank, whose work is pri- 

 marily commercial, and not research. 



Rise in New Zealand Lambing Percentage 



Authenic reports from New Zealand, 

 states Commerce Reports, place the esti- 

 mated percentage of lambing for 1917 

 at 88 per cent, as compared with 86 per 

 cent for 1916. This means a gain, 



since there is an increase of between 

 200,000 and 300,000 ewes for the 

 year. The entire outlook for the 

 sheep industry in New Zealand seems 

 promising. 



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