Variation in flowering characteristics in a clonal seed orchard of pinus brutia

Scions were taken from 28 plus trees of Pinus brutia at Çameli-Göldağı (Denizli) origin in 1985. The scions were then grafted in the same year on suitable stocks, and the grafted trees were grown under care for one year at Antalya Forest Nursery. The grafted trees were transplanted with 8x8 meter spacing in a seed orchard in Asar district near Antalya in 1986. * In order to study flowering characteristics a total of 280 orchard trees [10 trees (ramets) from each of the 28 clones] were randomly chosen in 1996 in the Asar Seed Orchard. Numbers of female and male flowers were determined on each tree, both in 1996 and 1997. Analyses of variance tests showed that there were significant differences among the clones and between the years in the numbers of both female and male flowers. Duncan's Multiple Range Tests were employed to determine the clones that are different from each other. When the clones were ranked in descending order for the female flower production, the top seven clones (25 % of all clones in the orchard) contributed 34.3 % of the total female flowers in the orchard in 1996, and 34.9 % in 1997. In 1996 Clone No 21 was in the first rank with 135 female flowers per tree, whereas in 1997 Clone No 3 was in the first rank with 428 female flowers. On the average, trees produced higher number of flowers in 1996 than in 1997. Five of the top seven clones (Clones No 1, 3, 6, 14 and 21) in female flower production in 1996 are also included among the top seven in 1997. When the clones were ranked in descending order for the male flower production, the top seven clones contributed 61.3 % of the total male flowers in the orchard in 1996, and 56.4 % in 1997. Clone No 1 was in the first rank both in 1996 and 1997 with 3476, and 8036 male flowers per tree, respectively. Five (Clones No 1, 4, 6, 9 and 26) of the top seven clones in male flower production in 1996 are also included among the top seven in 1997. The top of seven clones that produced the highest number of female flowers are not necessarily the same top seven clones that produced highest number of male flowers. Yet, two clones (clones 1 and 6) were among the top seven clones in both female and male production both in 1996 and 1997. On clonal basis, male flowers showed higher variation (higher coefficient of variation) compared to female flowers in both observation years. Average numbers of both male and female flowers per tree were higher in 1997 compared to that inl996. 76The results indicate that, the contribution of each clone to the common gene pool of the Pinus brutia seed orchard was not equal; which is deviated considerably from an ideal expectation of equal clonal contribution. Apparently, some clones acted as predominantly 'male', while other acted as 'female'. The results reported here were parallel to those reported earlier for some other Pinus species. Clone x year interaction was significant for number of female flower at 0.05 level. It was found that mid-ranked clones were the main contributors to the interaction variance. But the top ranked clones were relatively stable from year to year in terms of female flower production. On the other hand, clone x year interaction was not significant for male flower production. In overall female flower production covering both observation years, Clone No 3 produced 6% of the total female flower production. Clone No 1 was in the first rank (13%) in the contribution of the total male flowers produced in both years in the seed orchard. Female flowers were mainly located on the middle and upper part of the tree crown, whereas male flowers were mainly concentrated on the middle and lower parts. The clones that produced higher number of flowers in 1996 also had higher number of one- year-old cones in 1997 (r=0.95***). Average proportion of female flowers, which developed into one-year-old cones in the whole seed orchard, was 56.6 %. Phenotypic correlations among the character pairs were also investigated. There was positive and significant correlation for both female (r=0.64***) and male (r=0.84***) flower production between two subsequent years, implying that clones were relatively consistent over the years for flower production. Taller clones tended to show lower value for cone production indexes (r=-0.43*), which implies allocation of higher proportion of energy to vegetative growth rather than to development female flowers into cones in taller trees. Similarly, clones with higher number of branches showed lower number of male flowers (r=-0.44*), which suggest that crown density create a shading affect mostly on lower branches that subsequently lead into reduction of male flowers. There were considerable within and among clonal variation for the phenological stages of both female and male flowers. Certain clones had longer receptivity and/or longer pollen shedding periods, while some other clones had shorter periods. In general, 77receptivity stage of female flowers started earlier than that of pollen dispersal stage, both on clonal bases and in whole seed orchard scale. It was found that average air temperatures at the time flowering period (March, April, May) had considerable effect on the commencement and duration of different flowering stages. 78