Key phenological events in globe artichoke (<i>Cynara cardunculus</i> var. <i>scolymus</i>) development

A priority for the field vegetable grower is to be able to schedule a regular supply of product throughout the growing season. This requires a predictive framework, based on the identification of key developmental events of the crop, and an understanding of how genotypic and environmental factors interact to determine plant development. Four globe artichoke (Cynara cardunculus var. scolymus) cultivars, representing the existing phenological range, were grown in a field experiment, and a range of environmental conditions was imposed by varying both the timing of the first irrigation (which determines the initiation of regrowth) and by repeating the experiment across two locations and 2 years. The timing of the appearance of the main stem capitulum was sensitive to both the growing environment and the cultivar. These differences persisted till flowering and were correlated with final leaf number. As the plant developed, the phyllochron decreased, resulting in three values of phyllochron, each of which was responsive to genotype, and hardly to environment. The timing of the first change in phyllochron was associated with the final leaf number and the appearance of the capitulum. For all the cultivars, the rate of development fell and the final leaf number increased as the length of the photoperiod increased. The later flowering cultivars shared a similar vernalisation requirement, but 'Spinoso sardo' did not require a cold period to flower. Leaf length reached a peak before the beginning of stem elongation, and maximum leaf length was correlated with final leaf number. The sensitiveness of the phyllochron to the genotype, and of the number of leaves and the timing of the appearance of the capitulum to both genotype and environment makes them suitable as variables in developmental models. The importance of the final number of leaves is not only because of its phenological significance, but also because of its effect on the ability of the canopy to intercept radiation

Development of durum wheat and triticale cultivars as affected by thermo-photoperiodic conditions

The understanding of the interaction between thermo-photoperiodic conditions and the genetic control of anthesis date is fundamental in explaining the environmental adaptation of durum wheat and triticale cultivars. The development of 8 durum wheat (Triticum turgidum L. var.durum) and 2 triticale (x Triticosecale Wittmack) cultivars was studied at 3 sowing dates (September, November, and March) by observations on apex development, number and rate of leaf appearance, spike fertility, and number and length of elongated internodes. Variation in anthesis date was mostly explained by the total number of leaves, which ranged between 8.3 and 15, and hence by the duration of the phase of leaf primordium production. Total leaf number also affected the length of the subsequent phase until flag leaf appearance. The phyllochron was influenced by both sowing date and genotype, and was minimum in the March sowing (87 degree-days). The genotypic variability in phyllochron was due either to the variations in leaf number or to genotypic intrinsic differences. Time to terminal spikelet stage was related to the number of spikelets per spike and to the number of elongated internodes, although stem length depended more on internode length than on internode number. The number of spikelets per spike was associated with leaf number, but their relationship was affected by the thermal conditions during spikelet primordium initiation. No differences were observed between wheat and triticale cultivars, apart from the number of spikelets per spike

Towards a Comprehensive Climate Change Agreement in Copenhagen

The European Commission publicized on 28 January 2009 a Communication titled "Towards a comprehensive climate change agreement in Copenhagen". This Communication addresses concrete issues that will need to be addressed in Copenhagen to come to a successful outcome, including targets for developed countries and actions for developing countries; financing; and building an effective global carbon market. The Communication is accompanied by a Staff Working Document (SWD) "Extensive background information and analysis". This SWD gives scientific background to the Communication and includes various alternative mitigation scenarios and modelling results on a global scale. Several research institutes contributed to this SWD (JRC-IPTS , JRC-IES , IIASA , MNP , KUL ) using a broad set of models (POLES, GEM-E3, IMAGE, G4M, GLOBIOM, GAINS).JRC.J.2-The economics of climate change, energy and transpor