606 FUNDAMENTALS OF FRUIT PRODUCTION 



"Fluctuations in growth of individuals within particular groups are decided, 

 often extreme. In general, differences become less with increase in age, provided 

 the trees remain healthy. 



"There is no tangible basis upon which to establish the assumption that 

 robust scions are superior to scions of small diameter for purposes of pro- 

 pagation." 



These conclusions apparently differ from those of Shamel, Scott and 

 Pomeroy working with citrus fruits. However, it should be noted that 

 sucker growth was found in great abundance only in citrus trees that were 

 "off type" individuals and it was to trees from such parentage that these 

 workers particularly referred. In other words it was only because excess- 

 ive sucker growth was correlated with a certain type of degeneration that 

 propagation from wood of that kind yielded unsatisfactory results in 

 practice. The evidence seems to warrant the conclusion that normal 

 buds, whether borne on slow or rapid growing shoots or on suckers, are 

 satisfactory for propagation, provided they are healthy and do not come 

 from limbs that are bud mutations. Furthermore, it justifies the nursery- 

 man in propagating from the nursery row, i.e., from young trees, provided 

 there is no question of identity. 



In General. — At present comparatively little is known as to the extent 

 of bud mutation within the various fruit groups. It is possible that 

 opinions regarding pedigreed trees may need revision. Considering the 

 present state of knowledge the prospective purchaser should ascertain 

 accurately just what is meant by the term "pedigreed" stock in each 

 case, the extent to which such nursery stock differs from the ordinary in its 

 source and in its later performance record. Not until then can he tell how 

 to reckon its comparative value. 



There is no doubt that occasional variations occur and can be per- 

 petuated, but there is also no doubt that much of the variation between 

 trees in the same orchard is due to soil variations or to differences in 

 stocks and that these variations are not perpetuated. The fact that stock 

 is propagated from a superior individual indicates a bare possibility that 

 it is superior but it does not establish a probability that it is, much less 

 a certainty. 



Suggested Collateral Reading 



Webber, H. J. Selection of Stocks in Citrus Propagation. Calif. Agr. Exp. Sta. 



Bui. 317. 1920. 

 Burbidge, A. F. W. The Propagation and Improvement of Cultivated Plants. 



Pp. 57-86. London, 1877. 

 Bonns, W. W., and Mertz, W. M. Experiments with Stocks for Citrus Calif. 



Agr. Exp. Sta. Bui. 267. 1916. 

 Bioletti, F. T. Grape Culture in California. Calif. Agr. Exp. Sta. Bui. 197. 1908. 

 Bioletti, F. T. Resistant Vineyards. Calif. Agr. Exp. Sta. Bui. 180. 1906. 



