Genetic variation for carbon isotope composition in Juglans regia L.: relationships with growth, phenology and climate of origin

Among the traits of breeding interest for the common walnut tree Juglans regia L., characteristics such as timing of budbreak and leaf fall, water-use efficiency and growth performance are regarded as being of utmost relevance in Mediterranean conditions. The authors evaluated intraspecific variation in $\delta$13C (carbon isotope composition, surrogate of intrinsic water-use efficiency, WUE$_{\rm i}$) for 22 J. regia families grown in a progeny test under supplementary irrigation, and investigated whether such variation correlated with climatic indicators of native habitats. The genetic relationships between $\delta$13C, growth and phenology were also assessed during two consecutive years. Overall, the most water-use-efficient families (i.e. with higher $\delta$13C), which originated mainly from drought-prone provenance regions which have a high vapour pressure deficit and low rainfall, exhibited less height growth and smaller DBH. Using a stepwise regression procedure, $\delta$13C was included as the main explanatory variable of genotypic variation in growth traits, together with growing season duration (for DBH in both years) and flushing (for height in 2007). It was concluded that WUE$_{\rm i}$ is largely unconnected to phenology effects in the explanation of growth performance for J. regia, therefore suggesting the opportunity of simultaneously selecting for low WUE$_{\rm i}$ and extended growing period to maximise productivity in non-water-limited environments.

El neolític antic i l"inici de l"edat del bronze a les excavacions del nou conservatori del Liceu

[cat] En aquest article es presenta l"estudi interdisciplinari de les ocupacions prehistòriques recents (neolític i inici de l"edat del bronze) localitzades durant la construcció del Conservatori del Gran Liceu de Barcelona, al barri del Raval de la mateixa ciutat. Les restes ocupacionals corresponen a un assentament amb evidències d"estructures de combustió i diversos elements de suport. Hi destaca la conservació d"alguns magnífics fogars, així com un conjunt de materials abiòtics i biòtics que permeten augmentar el coneixement de les primeres comunitats agrícoles del Pla de Barcelona. [spa] En este artículo se presenta el estudio interdisciplinar de las ocupaciones prehistóricas recientes (Neolítico e inicio de la Edad del Bronce) localizadas durante la construcción del Conservatorio del Gran Liceo de Barcelona, en el barrio del Raval de la misma ciudad. Los restos de ocupación corresponden a un asentamiento con evidencias de estructuras de combustión y otros elementos de soporte. Entre ellos destaca la conservación de algunos magníficos hogares así como un conjunto de materiales abióticos y bióticos que permiten aumentar el conocimiento sobre las primeras comunidades agrícolas del llano de Barcelona. [eng] This paper presents the interdisciplinary study of the recent prehistoric occupations (Neolithic and Early Bronze Age) found during the construction of El Liceu Conservatoire in Barcelona"s El Raval district. Occupational remains correspond to a settlement with traces of combustion structures and several supporting elements. It emphasises the preservation of some magnificent fireplaces and a set of archaeological abitoic and biotic materials that can increase knowledge of the first farming communities in the Barcelona plain. [fra] Cet article présente l"étude interdisciplinaire des occupations préhistoriques récentes (néolithique et début de l"âge du bronze) localisées lors de la construction du Conservatoire du Grand Théâtre du Liceu (opéra) de Barcelone, dans le quartier du Raval. Les vestiges d"occupation correspondent à un établissement présentant des structures de combustion et différents éléments de support. On y remarque la conservation de quelques magnifiques foyers ainsi qu"un ensemble de matériaux abiotiques et biotiques qui peuvent enrichir les connaissances sur les premières communautés agricoles de la plaine de Barcelone.