Many fodder crops are characterized by biological traits, and their combined cultivation and fuller use of life factors ultimately have a significant impact on the total yield, improvement of quality indicators compared with the yield of crops sown in a monoculture. Grass mixtures use solar energy, soil fertility and other biotic factors most fully, due to the placement by tiers of crops both aboveground part and root system of the constituent crops. The most productive fodder mixtures for 2021-2022 characterized by high quality aboveground biomass were identified: corn of RRDTI variety 1 with vegetable vetch Aliya variety (26.5 t/ha). Dry mass yield per hectare is significantly higher in mixture with high-protein crops than in single-species crops. Studies were carried out in the experimental field of Russian Research and Design and Technological Institute of Sorghum and Corn Rossorgo.

The presence and structure of lignins have an important impact on the quality of a wide range of different plant-based resources. The mechanical and degradability properties of the different tissues of the plant material largely depends on the lignification of the cell walls, the histological features such as the cellular morphology or the relative amount of each tissue fraction, the composition and the spatial distribution of tissues within plant organs. Many studies, in particular devoted to increase the degradability of plant cell walls, showed a wide range of techniques for studying lignin and polysaccharides. By combining staining, microscopic methodologies and imagery we reached a high level of cellular resolution. Large scale studies of anatomical features (Zhang et al. (2013), Legland et al. (2017), El Hage (2018)) on maize showed links between anatomical traits in stalk and the detection of candidate genes, the biomass stalk anatomical traits and the biochemical or physical properties of the biomass and led to the identification of candidate genes. Recent studies on sorghum mobilized quantitative anatomical internode analysis to better understand response to water availability (Perrier et al. (2017), Luquet et al. (2018)) and biogas production (Thomas et al. 2021). However most of these studies focused on a single internode level of the stem. In this presentation we highlight the intra stem variability of a set of morphological, anatomical and biochemical traits analyzed in successive elongated internodes along the stem of two contrasted genotypes for composition and hydrolysis yield over 3 years. Two approaches of anatomical studies are presented: colorimetric information and multispectral autofluorescence imaging to focus on phenolic compounds.

Sorghum genetic diversity features morphological races such as Bicolor, Caudatum, Durra, Kafir and Guinea, as well as geographical origins throughout Africa and Asia. Among the different genetic groups, the Guinea margaritiferum subrace receives a particular status suggesting a secondary domestication event. Whole genome sequencing data provide new ground to better understand sorghum genetic diversity. We have access to the wealth of sequencing data produced by the Sorghum Genomics Toolbox (SGT) project. We have complemented the SGT sample with 37 accessions that have extended the coverage of the margaritiferum subrace. After a new SNP call, we recovered a dataset of 972, mostly cultivated, accessions characterised with 31 million SNP loci. We performed principal component analyses (PCAs) after applying different thresholds for minimum allele frequency and for missing data. Overall, we obtained high-level components that differentiate Guinea margaritiferum materials, confirming the special status of this subrace. On this basis, we are characterising the distribution of this differentiation along the genome and the extent of genetic exchange between the margaritiferum subrace and the other cultivated forms. The data is ready to be accessed on our South Green platform using the Gigwa data management tool and various analytical options that will make it an excellent resource for data mining by researchers and students interested in germplasm management and improvement.

Sorghum is among the most important cereals in the world in terms of human and animal nutrition and contributes to several bio-based value chains, including bioenergy production. The development of varieties fitting the expectations of these different end-products requires a better understanding of the genetic determinism of the traits contributing to the targeted ideotypes. In this context, the objectives of this study were to estimate the general and specific combining abilities of biomass quality and production related traits, explore their correlations and assess the heterosis levels achieved. To reach, these goals a factorial design based on 10 female and 16 male parents that were selected for their General Combining Abilities (GCA) for biomass production has been developed. One hundred and forty seven hybrids were evaluated on 3 sites together with their parental lines in 2014. Heritability of 0.69, 0.79 and 0.90 were observed respectively for the dry matter yield, lodging at maturity and biomass digestibility. Correlations' analysis between hybrid genetic values and combing ability components showed that hybrid performance is mainly correlated with the male parents GCA and depends only weakly of the female GCA. Higher best parent relative heterosis (up to 49%) was observed for biomass yield compared to biomass digestibility (up to 9%) and a negative genetic correlation (-0.54 for the blup values and -0.6 for the GCA values) was observed between biomass yield and digestibility in the factorial design. The best hybrids were selected and evaluated on 4 and 3 sites respectively in 2015 and 2016. In addition to allow the identification of elite parental lines that will be used in future crosses, this study underlined the negative correlations between biomass production and quality that will need to be tackled and the lack of strategies to accurately predict heterosis in single cut forage sorghum.

The development of climate-smart varieties requires the identification of haplotypes influencing traits of agronomic interest with well-defined effects across environments. For that we need advanced crossing schemes, multi-environment characterization, and state of the art statistical methodology. In this contribution, we present a sorghum multi-reference back-cross nested association mapping population composed of 3901 lines produced by crossing 24 diverse parents to three elite parents from West and Central Africa (WCA-BCNAM). This population is potentially one of the most relevant sorghum resources for research and breeding purposes in that region. The population was characterized in environments contrasting for photoperiod, rainfall, temperature, and soil fertility. To analyse this multi-parental, multi- environment design, we developed a new statistical methodology for QTL detection and parental effect estimation. In addition, envirotyping data were integrated in our models to determine the influence of environmental covariables on the genetic effects. We used this strategy to analyse the genetic architecture of flowering time and plant height, which represent key adaptation mechanisms. Our results allowed a better characterisation of well-known genomic regions impacting flowering time concerning their response to photoperiod with Ma6 and Ma1 being photoperiod sensitive and candidate gene Elf3 being insensitive. We also accessed a better understanding of plant height genetic determinism with the combined effects of phenology dependent (Ma6) and independent (qHT7.1 and Dw3) genomic regions. The strategy implemented in this work illustrates the need of synergy between genetics, breeding, and statistical genetics to harness the potential of sorghum in a changing climate. The resources and tools developed in this project should serve the whole sorghum community, for example by providing relevant elite parents for breeding programs.

The potential of sorghum to cope with biotic and abiotic constraints could enable it to contribute to global food security in the context of climate change. However, the low digestibility of the grain reserve proteins (called kafirins) by gastrointestinal proteases is hampering its wider use for food and feed. The structure of the protein bodies in which are stored the kafirins is potentially responsible of this defect. The molecular mechanisms underlying the development and modification of kafirin-containing protein bodies are still largely unknown. In this context, our objective is to decipher the molecular mechanisms involved in the regulation of the content and digestibility of sorghum grain reserve proteins. The evolution of the transcriptome was monitored during the grain development of the Macia genotype, and supplemented by an analysis of gene co-expression networks (GCN). In parallel, the protein content of the grains and their in vitro digestibility were measured. Analyses of GCN allowed the identification of transcription factors (TFs) potentially regulating the mechanisms of protein reserve establishment. We identified coexpression modules involving kafirin genes and genes orthologs to TFs already known in maize, rice and arabidopsis. In those modules, we also identified not yet identified TFs. In the future, we plan to evaluate the role of these TFs by a simplified cellular overexpression system in sorghum protoplasts. We will also investigate variability of protein content and digestibility in a panel representing sorghum worldwide genetic diversity and European commercial offer, in order to perform GWAS analyses and phenomic and genomic predictions.

One of the determinants of the low productivity of the millet and sorghum sectors in Senegal is the low use of improved varieties in rural areas. On average, the yields obtained on the farm are four to five times lower than those of the improved varieties obtained on the station (Diallo and Ndiaye, 2022). This low adoption is however attributable to a dysfunction of the seed system. This article aims to diagnose the level of collaboration and interaction of actors in order to find the bottlenecks that prevent the evolution of the seed system. A qualitative analysis of the survey data, based on the innovation spiral model of Wielinga (2016) and the Agricultural Innovation System (AIS) approach, was made. This analysis has shown that, in parallel with the hypothesis put forward at the start, the poor performance of the Senegalese seed system is attributable to the lack of interaction of the various actors that make up the system. Indeed, the analysis shows five major flaws that block the process : - A linear diffusion process - Weak synergy between ISRA and ANCAR - Late notifications from the State for seed orders to be subsidized - Insufficient pre-bases produced by ISRA - The presence of non-professional actors in seed multiplication activities The proper functioning of the seed system would then suppose the simultaneous application of policies on these five bottlenecks. Thus, the article proposes a retroactive dissemination model that makes it possible to simultaneously correct the shortcomings of the current system.

When the rates of leaf initiation and leaf emergence are identical, as in rice, the rank of the last initiated leaf can be directly determined by the last emerged leaf ranking. Oppositely, when plastochron is shorter than phyllochron, as in maize and sorghum, the number of growing leaves inside the whorl increases with time and prevents estimating the panicle initiation date on simple visual observation. The objective of this work was to quantify the relationships between leaf initiation, leaf appearance and leaf ligulation in three contrasted sorghum genotypes (two parents and their hybrid) in order to 1) estimate the date of panicle initiation based on the number of appeared leaves and 2) investigate the potential heterosis effect. The appearance rate in thermal time varied according to the genotype, with the hybrid having a faster rate than its two parents. Leaf initiation rate also presented a variability within the three lines, the hybrid having an intermediate position. The shorter phyllochron in the hybrid corresponded to its higher growth rate, expression of an heterosis effect. The relationships between leaf initiation and appearance were highly significant and genotype-specific. Nevertheless, the slopes of the regressions were close, leading to small differences in the prediction: thus when the 12th leaf just emerges, between the 19th or 20th leaf is initiated according to the genotype. Therefore, using a single model across the three lines does not increase the rank error and can be applied in breeding programs to estimate the date of panicle initiation. The result needs to be confirmed on a larger panel of sorghum genotype in order to test the model robustness. The main limitation for field application remains the estimation in a genotype of the total number of leaves to be developed before panicle initiation, trait that can vary in photoperiod sensitive cultivars.