Larix decidua polonica in Western Europe First results from a joined European network of progeny trials Pâques Luc E. INRA-Orléans Unité AGPF

Context  European larch shows a large intra-specific variation,  Populations from Central Europe are of special interest (core of the gene pool), (from Schober 1981 and 1985, in Weisgerber and Sindelar 1992).

Context –ecological flexibility –behaviour to drought stress –vigour –canker-resistance –wood quality But –stem form is mostly poor. Central Poland origins show original traits in terms of : Ex.Curnel et al Results gained and published from IUFRO international trials with a limited set of provenances

Objectives to broaden the geographic origin of the provenances, to get a better picture of the structuration of the genetic variability, to examine seed transfer possibilities from East to West, to confirm the interest of polish larch for wood quality and problems connected with stem straightness. to broaden the breeding population, to take benefits of polish larch properties in interspecific hybridization.

Material & Methods Joined cone collection by INRA & IBL in Mont Gory Swietokezyski in Dec.1987, 157 open-pollinated progenies, randomly chosen ( except distances and level of fructification ), in 4 autochtonous ‘stands’ ( mainly old natural reserves ). material shared with IBL and SRFGx

1994 Field trials 8 progeny trials + 2 conservation plots

Ecologically contrasting sites From less than 150 m up to 750 m asl. From very low up to high pH soils

Survival Mortality (%) 7-10 yrs Globally a better survival than other populations & species Mortality (%) yrs

Sensitivity to drought ? 2003 heat-drought wave : Bort Top-dieback may be a serious problem for sudetan & polish larches

Drought / growth cracks ? PlachetBortArceyCroze polonica25 (5-57%) 11 (0-50%) 6 (0-27%) 1 (0-11%) sudetica13 (12-14%) 4 (0-9%) 00 alpine7000 japanese0000 hybrids16 (6-22%) 5 (0-15%) 1 (0-8%) 1 (0-3%) Higher frequency of stem cracks in polish larch on all sites

Wind firmness Polish larch : nearly 50% stem damaged by wind throw

Meria laricina A major recurrent problem in moist mild spring in Bort  Polish larch (but also other EL): high sensitivity  Hybrid larch & Japanese larch: low sensitivity

Well…well… MortalityTop- dieback ‘Drought’ cracks Wind firmness Meria Arceyxx (X) nnn Plachet n (X) xx nn Bort n xxx Croze nnnnn Rance n ???? Villancexx ???? No mention of canker

And growth… and straightness…?

Field trial networks and difficulties Experimental design Site preparation Spacing Thinning Traits assessed and timing thinned

Site ‘fertility’ yrs Correction for spacing/ mortality/ thinning/ age assessment Polish sites more vigorous than FR/BE sites (up to 4x more BA MAI !!) ? In France, ratio of 1 to 3 among sites.

Site ‘fertility’ Blue : 4-7 yrs /yellow : yrs Blue: yrs / yellow: yrs (thinning in Bort & Croze)

Relative performance of polonica vs sudetica and other larch taxa In France Height: polonica >= to other provenance or taxa Girth: idem but < to hybrids In Belgium (Height: polonica < to others) Girth: idem

Stem straightness crooked straight From J.Kowalczyk Stem form: Worst on Polish sites Best on French sites

Relative performance of polonica vs sudetica and other larch taxa Globally polonica - < to hybrid larch, - to sudetica - to Japanese larch

Summary sudeticaJLHL Villance survival eq<< growth eq<< stem form <<< Rance survival eq<< growth eq<< stem form <<eq Bort survival >>eq>> growth >>eq<< stem form eq << Croze survival <eq growth >> << stem form eq << Arcey survival eq>> growth >> < stem form eq << Plachet survival eq>>> growth >> << stem form eq>><<

But a large variability among progenies exists…

Perspectives… Prog = crop on best 30 trees in PL stand SO = clonal seed orchard with best 30 clones

Conclusions Polonica larch is globally valuable for French conditions on most sites; questions about the Belgian sites Perspectives for selection are favourable and needed (stem form) Nevertheless care with regards to behaviour to some abiotic (heat/drought/wind) and biotic stress (Meria) is needed on susceptible sites (ex. Bort, Plachet).