Rainfed agriculture would remain the dominant source of staple food production and the livelihood foundation of the majority of the rural populace in semi-arid West Africa. Prolonged dry spells during the growing season often lead to significant crop yield losses, a situation that is expected to be exacerbated by climate change. In this study, impacts of climate change on the sorghum production system in West Africa semi-arid tropics was analysed using the most accessible process-based crop models (DSSAT, APSIM and Samara) and simulated at six stations under rainfed conditions. The mid-century future climate predictions by 2069 indicate the productivity of grain sorghum would be diversely affected due to the differences in the GCMs projections in terms of temperature and rainfall. On the average, climate change is projected to reduce low photoperiod sensitivity genotype (CSM63E) grain yield to the tune of 13%, and by 7% for both medium photoperiod sensitivity genotype (CSM335) and high photoperiod genotype (IS15401) across the selected sites. Results also indicate that adaptation strategies like longer grain filling period and sowing date reduced the vulnerability on both the medium and high photoperiod sensitivity genotypes (CSM335 and IS15401) compared to low photoperiod sensitivity genotype (CSM63E). As obtained from the study, proper genotypic calibrations and evaluations of crop models could be used to explain the expected outcomes of future climate conditions on the diverse photoperiod sensitivity sorghum genotypes available across semi-arid area. Also, these results would serve as reliable tools towards the understanding of future climate change and adaptation options to be implemented, which could be shared among farmers and development partners interested in food security issues in West Africa semi-arid zone. (Texte integral)
Mixed crop–livestock systems play an important role in global food production and livelihood provision of millions of rural households. Climate change is projected to alter the functioning and productivity of these systems. Although for many regions the impact of climate change is projected to be large, many uncertainties persist, in particular with respect to impacts on livestock and grazing components, whole-farm dynamics and heterogeneous farm populations. Using an integrated modelling framework we simulated fodder and grassland productivity for current and future climate scenarios. This data was subsequently used as input in a dynamic livestock model LIVSIM to investigate climate change impacts on animal productivity. The modelling framework simulates entire farm populations, thus capturing the effects of farm heterogeneity. Livestock-related output variables included milk production, herd dynamics, calving and offtake rates, and mortality rates. In integrated assessments, these livestock outputs are used in economic models at the household level. The modelling approach was applied across four distinct regions, including southern Africa, West Africa, Pakistan and India. This allowed capturing a wide diversity in farming systems and climate scenarios. Also various adaptation options targeting the crop, animal or grazing land components of mixed crop-livestock systems were investigated. Strong impacts of climate change and adaptation packages on livestock productivity were found in particular where impacts on feed quantity and quality were large. The differences in outputs were attributed to differences in growth-defining and growth-limiting factors across the four regions.
Improving rice models for more reliable prediction of responses of rice yield to CO2 and temperature elevation . International Crop Modelling Symposium
Les associations de cultures cereales-legumineuses s'inscrivent dans une logique d'intensification durable. Cependant, dans les zones saheliennes et soudano-saheliennes du Burkina Faso, les rendements en association sont generalement faibles. Notre etude a pour objectifs de caracteriser la pratique d'association culturale la plus pratiquee par les producteurs, identifier les facteurs determinant des rendements et proposer des pistes d'amelioration. Des focus groupes, des enquetes individuelles aupres de 170producteurs et un suivi de 80 parcelles paysannes ont ete realises dans trois communes en zone soudano-sahelienne. Il ressort que l'association traditionnelle du sorgho et du niebe au poquet est dominante a 98%. Elle se pratique essentiellement avec des varietes locales (92% pour le sorgho et 67% pour le niebe). Les rendements sont tres variables et faibles avec en moyenne 416 kg/ha de sorgho et 240 kg/ha de niebe. Les analyses multivariees ont permis d'etablir des typologies d'exploitations familiales, de types de sol et d'itineraires techniques culturaux. Des variables significatives de differenciation des rendements ont ete identifiees. Le nombre de personnes a charge (p=0,001), de daba/houes (p=0,002), l'activite secondaire (p=0,005), le taux de limon du sol (p=0,0008) et les types de sols (p=0,01) sont celles qui ont influence les rendements en sorgho. Tandis que les rendements de niebe ont ete significativement influences par le nombre de petits ruminants (p=0,03), de daba/houes (p=0,008), l'activite secondaire (p=0,01), l'azote total (p=0,001) et la matiere organique du sol (p=0,004). Les pratiques culturales s'etant averes moins impactant sur les rendements du sorgho et du niebe, l'amelioration des performances du systeme pourrait passer par une diversification des varietes utilisees.
G ibberella circinata (anamorph F usarium circinatum ) is a harmful fungus infecting pine trees that has been subject to E uropean Union emergency phytosanitary measures since 2007. This fungus is spread over long distances primarily via pine seeds, consequently reliable detection tools and methods are needed to test pine seed lots imported and marketed in the EU. Several detection methods are available in the scientific literature but very limited validation data is available. For that purpose, one E uropean EUPHRESCO project called ‘ G ibcir‐ D iagseed’ was launched, involving 10 countries. This project aimed to select and validate one or more diagnostic procedures targeting this pest via inter‐laboratory tests, as well as a suitable sampling method. Performance criteria were calculated for three procedures chosen by participants: isolation followed by morphological characterization, isolation followed by conventional PCR and biological enrichment followed by real‐time PCR . The results showed that all three procedures provided acceptable performance criteria but also demonstrated that none of them could generate 100% of correct results. Regarding the sampling issue, the N ational P lant P rotection O rganizations consultation enabled an agreement to be reached on the number of seeds to be tested: 400 per sample, for a 95% confidence level that an infection of at least 1% will be detected.
Abstract Previous studies have shown that activation of the signal transducer and activator of transcription 5 (STAT5) plays an essential role in leukemogenesis mediated through constitutive activated protein tyrosine kinases (PTK). Because PIM-1 is a STAT5 target gene, we analyzed the role of the family of PIM serine/threonine kinases (PIM-1 to PIM-3) in PTK-mediated transformation of hematopoietic cells. Ba/F3 cells transformed to growth factor independence by various oncogenic PTKs (TEL/JAK2, TEL/TRKC, TEL/ABL, BCR/ABL, FLT3-ITD, and H4/PDGFβR) show abundant expression of PIM-1 and PIM-2. Suppression of PIM-1 activity had a negligible effect on transformation. In contrast, expression of kinase-dead PIM-2 mutant (PIM-2KD) led to a rapid decline of survival in Ba/F3 cells transformed by FLT3-ITD but not by other oncogenic PTKs tested. Coexpression of PIM-1KD and PIM-2KD abrogated growth factor–independent growth of Ba/F3 transformed by several PTKs, including BCR/ABL. Targeted down-regulation of PIM-2 by RNA interference (RNAi) selectively abrogated survival of Ba/F3 cells transformed by various Fms-like tyrosine kinase 3 (FLT3)–activating mutants [internal tandem duplication (ITD) and kinase domain] and attenuated growth of human cell lines containing FLT3 mutations. Interestingly, cells transformed by FLT3 and BCR/ABL mutations that confer resistance to small-molecule tyrosine kinase inhibitors were still sensitive to knockdown of PIM-2, or PIM-1 and PIM-2 by RNAi. Our observations indicate that combined inactivation of PIM-1 and PIM-2 interferes with oncogenic PTKs and suggest that PIMs are alternative therapeutic targets in PTK-mediated leukemia. Targeting the PIM kinase family could provide a new avenue to overcome resistance against small-molecule tyrosine kinase inhibitors. (Cancer Res 2006; 66(7): 3828-35)
