586 ERNST J. SCHREINER 



performance of genetically superior individuals 3 not on the average 

 performance of families or lines. Such exceptionally superior individuals 

 may be obtained in early generations of intensive breeding, or even by 

 intensive selection in progenies derived from gene pools or natural 

 populations. Clonal tests of rust -free Pinus strobus ortets selected in 

 natural stands have demonstrated a broad range of inherent, individual 

 susceptibility; from high resistance (if not immunity) to extreme 

 susceptibility. The clones in a multiclonal variety could be changed on 

 very short notice, because the breeder could multiply superior genotypes 

 for commercial use without adulteration of the genotype and without 

 determining their combining ability to transmit the desirable qualities 

 or characteristics. 



LITERATURE CITED 



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New York. 485 p. 

 Allard, R. W. , and A. D. Bradshaw. 1964. Implications of genotype- 

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 Barber, John C. 1966. Variation among half-sib families from three 



loblolly pine stands in Georgia. Georgia Forest Res. Paper 37. 5 p. 

 Barnes, Burton V. 1964. Self- and cross-pollination of western white 



pine: a comparison of height growth of progeny. U.S. Dep. Agr. , 



Forest Serv. Res. Note INT-22. 3 p. 

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 Borlaug, Norman E. 1953. New approach to the breeding of wheat varieties 



resistant to Puccinia graminis tritici. Phytopathology 43: 467 (abstr.) 

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(ed.), Breeding pest-resistant trees. Pergamon Press, Oxford. 505 p. 

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Amer. Soc. Agron. Abstr., Annu. Meeting, 1953: 81. 

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