Malick Ndiaye1,2, Bertrand Muller3,4, Komla Kyky Ganyo5, Aliou Guissé6, Ndiaga Cissé6, Myriam Adam7,8,9. 1. Institut Sénégalais de Recherches Agricoles (ISRA), CNRA de Bambey, BP 53, Bambey, Sénégal. 2. Centre d'Etude Régional pour l'Amélioration de l'Adaptation à la Sécheresse (CERAAS), BP 3320, Route de Khombole, Thiès, Sénégal. 3. CIRAD, UMR AGAP Institut, 34398, Montpellier, France. 4. UMR AGAP Institut, Univ Montpellier, CIRAD, INRAE, Institut Agro, 34398, Montpellier, France. 5. Institut Togolais de Recherche Agronomique (ITRA), BP 1163, Lomé, Togo. 6. Département de Biologie Végétale, Université Cheikh Anta Diop de Dakar (UCAD), BP 5005, Dakar, Sénégal. 7. CIRAD, UMR AGAP Institut, 34398, Montpellier, France. myriam.adam@cirad.fr. 8. UMR AGAP Institut, Univ Montpellier, CIRAD, INRAE, Institut Agro, 34398, Montpellier, France. myriam.adam@cirad.fr. 9. Institut de l'Environnement et de la Recherche Agricole (INERA), 01 BP 910, Bobo Dioulasso, Burkina Faso. myriam.adam@cirad.fr.
Abstract
MAIN CONCLUSION: Plant traits of interest for sorghum breeders to develop dual-purpose varieties are stem diameter, flag leaf size, crop cycle, and number of grains per panicle. To develop dual-purpose varieties, breeders need to improve traits linked both to grain and biomass production. To identify these traits, we studied the phenotypic plasticity of eighteen traits and the performance of ten contrasting sorghum genotypes, used in West Africa. Trials were carried out in a randomized complete blocks design with four replicates from 2013 to 2016 in Bambey, Sinthiou Malem and Nioro du Rip in Senegal. The results revealed three plant types. The first type, "biomass production", contained genotypes IS15401 and SK5912, and was linked to cycle duration, leaf area, and plant height. The second type, "grain production", grouped the caudatum race sorghum 621B, F2-20 and Soumba, and was associated with the number of grains per panicle and the width of the flag leaf. The third group, "dual-purpose", corresponding to the genotypes Fadda, Nieleni and Pablo, combined some favourable traits for grain and biomass: stem diameter, internode length, number of green leaves and number of grains per panicle. The study showed that high and stable grain yields were associated with stability in flag leaf size, phenology and number of grains per panicle, and a high and stable biomass yield was associated with stability in stem diameter. Those stable plant traits might be of interest for sorghum breeders selecting to develop dual-purpose varieties.
MAIN CONCLUSION: Plant traits of interest for sorghum breeders to develop dual-purpose varieties are stem diameter, flag leaf size, crop cycle, and number of grains per panicle. To develop dual-purpose varieties, breeders need to improve traits linked both to grain and biomass production. To identify these traits, we studied the phenotypic plasticity of eighteen traits and the performance of ten contrasting sorghum genotypes, used in West Africa. Trials were carried out in a randomized complete blocks design with four replicates from 2013 to 2016 in Bambey, Sinthiou Malem and Nioro du Rip in Senegal. The results revealed three plant types. The first type, "biomass production", contained genotypes IS15401 and SK5912, and was linked to cycle duration, leaf area, and plant height. The second type, "grain production", grouped the caudatum race sorghum 621B, F2-20 and Soumba, and was associated with the number of grains per panicle and the width of the flag leaf. The third group, "dual-purpose", corresponding to the genotypes Fadda, Nieleni and Pablo, combined some favourable traits for grain and biomass: stem diameter, internode length, number of green leaves and number of grains per panicle. The study showed that high and stable grain yields were associated with stability in flag leaf size, phenology and number of grains per panicle, and a high and stable biomass yield was associated with stability in stem diameter. Those stable plant traits might be of interest for sorghum breeders selecting to develop dual-purpose varieties.