Variation in strobilus and cone production in clonal seed orchards of Anatolian black pine

Abstract

Anatolian black pine [Pinus nigra Arnold subsp. pallasiana (Lamb.) Holmboe] is an economically and ecologically important forest tree species with a natural distribution of 4.2 million ha, 32% of which is unproductive due to forest fire and other damages in Turkish forestry. The species is widely used in afforestation and conversion ofunproductive forests by deploying genetically improved seed from seed orchards because of high adaptation capability to various environmental conditions, and a target species of national tree breeding programme of Anatolian black pine. Estimated variation in reproductive characters can be used as an important guide for managing of seed orchards. The number of cones, female and male strobili were studied in three seed orchards established in 1991, 1993 and 1985 composed of 30, 30 and 34 clones each. Five grafts of each clone were evaluated from each seed orchard for three consecutive years (2022-2024). This study estimated the variation of broad-sense heritability (H2) and the correlation among cone and strobili production at the graft and clone level. Positive and significant (p<0.05) relations were calculated between female and male strobili within year in all orchards both ramet and clone levels, together with significant (p<0.05) relations among years for cone productions in the orchards. Significant (p<0.05) differences were found for the characters among clones and among years within orchard. Year x clone and clone x ramet interactions were generally significant (p<0.05) for the characters. Female strobili seemed a good predictor for cone production. However, the heritability in broad sense was mostly on average below 0.5 for the characters in each seed orchard except of female strobili in an orchard in year-24. It indicated that the reproductive characters under environmental control, and they could give to reflect to management practices.