Cotton plant topping combined with plant density has a positive effect on seed-cotton yield in the South Sudanian zone of Mali

Description of the subject. In Mali, cotton (Gossypium hirsutum L.) plays an essential role in economic and social activities in terms of income generation, rural organization and modernization of production systems. Cotton topping is a cultivation technique that reduces the growth in size of the cotton plant while favoring the production process. Objectives. The aim of this study was to evaluate the effect of topping combined with new sowing density on seed-cotton yield. Method. The study was conducted in Mali over two years (2020 and 2021) at the Finkolo research station in the Sudanian zone and one year (2022) in farmers’ fields. The experiment included two cotton varieties (NTAMS334 and BRS293) and two sowing densities, with or without topping cotton plants. The recommended sowing density of 80 cm x 30 cm with two plants per seed hole was compared with a new sowing density of 80 cm x 20 cm with one plant per seed hole. The main advantage of the new sowing density was the acceleration of the cotton plant's growth in height, thanks to the strong competition for light before topping. Results. The results showed that topping significantly reduced the average number of fruit-bearing branches per cotton plant (14 for the non-topped modalities and 10 for the topped modalities). The number of fruiting positions occupied per plant, boll load per plant, and seed-cotton yield increased with topping. The highest seed-cotton yields at the research station (2,238 kg·ha-1) and in farmers’ fields (2,391 kg·ha-1) were obtained with the new sowing density combined with topping. Conclusions. The results of this study can be used as a modifier of canopy and sowing density under cotton overgrowth conditions. L’écimage du plant de coton, en combinaison avec la densité végétale, a un effet positif sur le rendement des semences de coton dans la zone sud soudanienne au Mali Description du sujet. Au Mali, le coton (Gossypium hirsutum L.) est la principale culture de rente, aux côtés des cultures vivrières essentiellement destinées à l’autoconsommation et à la mise au marché du surplus. L'écimage du cotonnier est une technique culturale qui permet de réduire la croissance en taille du cotonnier tout en favorisant le processus d’élaboration de la production. Objectifs. L'étude visait à évaluer l’effet de l’écimage associé à différentes densités de semis sur le rendement du cotonnier. Méthode. L'étude a été menée pendant deux ans (2020 et 2021) à la station de recherche de Finkolo