Genetic variation in number of resin canals per needle of the Black Pine of Peloponnese

In December 1981 needle samples were taken from grafts of 8 reps of the black pine seed orchard of Peloponnese. The seed orchard was at the time of sampling three year old and includes 52 clones. In each rep 52 single tree plots were included. Five fascicles of needles per graft were collected from the middle section of the longer southern branch of the uppermost whorl. Free hand cross sections were made in the middle length of one needle of each fascicle and the number of resin canals were counted under the stereoscop. The total number of needles examined were: clone 52 X reps 8X needles per graft 5=2.080. Additionaly needles were collected from 10 ungrafted seedlings of the same with the grafts age and their resin canals were examined the same as previous way. The analyses of the data showed that: There are significant differences among the clones on the number of resin canals per needle. The overall mean of the Peloponnese population (2080 measurements) was found 8.4 with ranges among clone means 4-12.7 and among individual needles 2-16. The differences among clones are so large that many of them can be identified on the basis of this characteristic alone. Broad sense heritability on clone mean basis was found very high (H=0.97). The differences among the provenances from which the clones originate were also significant with trend of increasing number with the latitude. The southermost provenance of Taygetos had 7.0 resin canals while the northern of Feneos had 9.5. Besides the high overall mean of the grafts (8,4) ungrafted seedling had only 2.0 resin canals. This show clearly that the grafts maintain the physiological age of the adult mother trees and react like them. The correlation coefficient between number of resin canals and needle width and number of resin canals and needle thickness were also significant with values 0.57** and 0.47** respectively