New Zealand Journal of Botany abstracts

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VARIATION IN NATURAL POPULATIONS OF PINUS RADIATA IN CALIFORNIA
PART 4. DISCUSSION

Margot B. Forde

Forest Research Institute, Rotorua

Abstract This paper discusses the variation patterns of a number of branch, needle, and cone characters in samples collected from the three natural populations of Pinus radiata in California. A large proportion of the total phenotypic variation in these characters occurs between individual trees within each population. The Cambria population is less variable than the other two. Apart from those likely to be correlated in development, the variation patterns of different characters are not obviously associated. This is consistent with the outbreeding habit and the large complement of long and relatively undifferentiated chromosomes, which would promote high genetic recombination. Some of the morphological differences between samples from different parts of the populations seem to be related to habitat- These may sometimes represent a response to local selection rather than merely direct environmental effects. The Cambria population differs from the Monterey population in a number of features, principally in the average size of the cones and needles and in certain growth characteristics. The Ano Nuevo point population chiefly resembles that at Monterey, but is intermediate between the Monterey and Cambria populations in some important characters. No evidence of substantial introgression from P. attenuata or P. muricata was found.

N.Z. J. Bot. 2 : 486-501
(Received for publication, 7 October 1964)

PDF file of entire paper: medium quality (863K); (scanned from paper original: notes about this process)

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