A quantitative genetics approach was developed to identify the genomic regions that control relative water content (RWC) in field-grown barley. The trait was previously demonstrated to be a relevant screening tool of drought-tolerance in cereals, as well as a good indicator of plant water-status. The trait was measured at the heading stage on flag leaves recorded from 167 recombinant inbred lines grown in several Mediterranean sites (Montpellier, France; Meknès, Morocco; Le Kef, Tunisia). The results obtained confirmed that several genomic regions are implicated in the total phenotypic variation of RWC. A total of nine chromosomal regions were identified. One region situated on the long arm of chromosome 6H contains the most-consistent QTL obtained in the present study. This region was previously identified as controlling RWC, as well as leaf osmotic potential under water stress and osmotic adjustment, from an experiment conducted in growth-chamber conditions with the same genetic background. The confirmation of the role of this region in the genetic control of water and turgor status underlined its interest for breeding purposes in the Mediterranean area. In addition, the presence of several dehydrin loci in the same chromosomal area reinforce its interest for genomics analyses to confirm, or not to confirm, the implication of these genes in the variation of RWC.

SummaryA review is presented of genetic strategies deployed in a 3‐yr project on drought tolerance in barley. Data were collected on genetic, physiological and agronomic traits in non‐irrigated and irrigated field trials in Egypt, Morocco and Tunisia. A wide range of barley germplasm (developed from African and European cultivars, adapted landraces and wild barleys) was tested, and positive traits were found in each gene pool. The contrasting environments of the three North African countries had major effects on plant/genotype performance. Genetic effects were also detected, as were genotype × environment interactions.A range of strategies were deployed to investigate the physiology and genetics of quantitative traits associated with field performance. Quantitative trait locus (QTL) analysis was performed using backcross lines, recombinant inbred lines and doubled haploid mapping populations. A detailed genetic map was generated in the Tadmor × (ER/Apm) recombinant inbred lines, an important mapping population specifically developed by ICARDA (Centre for Agricultural Research in Dry Areas) and CIMMYT (International Maize and Wheat Improvement Center) to study drought. Quantitative trait loci (QTLs) for grain yield and other important morphological and physiological traits were also identified in a population of doubled haploids derived from F2BCj plants from a cross between a cultivar and a wild barley accession. Significantly, the wild parental line was found to contribute a number of positive alleles for yield.Effects of major developmental genes could explain many of the responses observed. QTLs were found to cluster around major genes controlling flowering time (sghI), plant stature (sdwI and arie.GP) and ear type (vrsl), and it is highly likely that the associations represent pleiotropic effects. Some QTLs were associated with candidate genes such as dehydrins and rubisco activase. One of the most significant results was the identification and generation of material that out performed the best local standards in the three participating North African countries; the selected lines have now entered local breeding programmes. The strategies adopted provided information on physiological traits, genotypes and genetic markers that could be used for marker‐assisted selection. Target QTLs and their associated genetic markers may be deployed in marker assisted selection programmes to match crop phenology to the field environment.

Au Bénin, la filière coton participe activement à l'économie nationale.Quatre nouvelles variétés issues du Centre de Recherches Agricoles Coton et Fibres ont été testées au Nord Bénin dans l'optique d'identifier la variété la mieux adaptée. Ces variétés ont été comparées à la variété H 279-1en vulgarisation. L'objectif est d'évaluer les comportements des variétés vis-à-vis des bioagresseurs et des maladies dans la zone. Le dispositif expérimental est un split plot à six répétitions, composé d'un facteur principal représenté par trois doses d'engrais chimique à savoir D1 (témoin) = 150 kg de NPKSB + 50 kg d'Urée à l'hectare, D2=200 kg de NPKSB + 50 kg d'Urée à l'hectare et D3= 250 kg de NPKSB + 50 kg d'Urée à l'hectare. Le facteur secondaire est composé de cinq variétés : H 279-1, I875-3, E956-2, H769-5 et H782-3. Il a été révélé que la pression parasitaire a été la même au niveau de toutes les variétés et ne dépend pas des doses d'engrais appliquées. Les variétés E956-2 et H782-3 sont moins sensibles à la bactériose que les variétés H 279-1, I875-3 et H 769-5 avec des valeurs respectivement de 0,37;0,29; 0,67; 0,68 et 0,59 plants attaqués sur 10 observés.

Water deficit in tropical countries is the main factor limiting agricultural production. This study aimed at evaluating the level of resistance to water deficiency of three local maize cultivars in Benin. The effects of water stress induced supply of 100 (control), 50 and 25 % of the Readily Usable Reserve (RUR) from the 40 th day after sowing to the end of the production cycle were studied. The experimental design used was a split plot with 4 replicates. Phenological, agro-morphological and agro-physiological parameters of plants were evaluated. Water deficit reduced plants height, root volume, root dry matter and total leaf area during the flowering stage. The date of female inflorescence setting was extended by water deficiency. Water deficiency also reduced the mean number of cobs per plant from 0.855 ± 0.38 (100% RUR) to 0.64 ± 0.019 (50% RUR) and 0.58 ± 0.17 (25% RUR). Furthermore, 1000 grains weight dropped from 264.63 ± 53.58 g (100 % RUR) to 223.88 ± 37.9 g (50 % RUR) and 217.63 ± 42.66 g (25% RUR). The cultivar Bafogbali was the most resistant to water stress. The variety EV DT 97 and the cultivar Souantokoui were the most affected by the water deficiency.