Selection of clones and genetic gain for second stage seed orchards of Scots pine (Pinus sylvestris L.) in western part of Latvia | Parastās priedes (Pinus sylvestris L.) klonu atlase Kurzemes zonas 2. kārtas sēklu plantācijas izveidei un sagaidāmais ģenētiskais ieguvums
2008
Jansons, A., Latvian State Forest Research Inst. Silava, Salaspils (Latvia) | Baumanis, I., Latvian State Forest Research Inst. Silava, Salaspils (Latvia) | Haapanen, M., Finnish Forest Research Inst. Metla, Vantaa (Finland)
Scots pine seed orchards secure physiologically and genetically valuable seed supply for forest nurseries and are the way to implement results of tree breeding work in praxis. Analyzed material consists of 10 progeny trials, 25-35 years old that together contains 363 plus-tree and clone open pollinated progeny families. Best families have been selected with growth potential indicator: yield of dominant trees. This trait in family mean level is less dependent from number of trees (per family) than total yield (standing volume) or dominant tree height (r**2=0,16, r=0,73 un r=0,24 respectively) and have almost no correlations with quality traits (r is less than 0,2). Selected 50 best families have 27% higher yield of dominant trees, compare to control (forest stand progenies). At the same time selected material have 3% lower maximal branch diameter, 5% lower average branch diameter (evaluated in grades) and 2% straighter stems (evaluated in grades) as control lots. We recommend, establishing the 2nd stage seed orchard, to develop few rows buffer zone from early flowering clone with a high breeding value and high male flowering intensity as well as to use the clones with possible synchronous flowering time to reduce pollen contamination in pollination of plantation clones. It is necessary to chose number of ramets per clone proportional to its breeding value - for the analyzed material in this way it was possible to increase genetic gain by 5%, while keeping constant genetic diversity (effective number of clones 22). It is suggested to use effective number of clones in seed orchards with tested clones 20-25.
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