Effet de l’environnement sur la croissance et la productivité des tubercules de sept (7) variétés de patate douce [ipomoea batatas (l.) lam] à chair orange au Niger.

The degradation of natural ecosystems (decline in soil fertility, regression of plant resources, desertification) poses real problems for farmers, especially for activities related to agriculture. Notwithstanding that rainfall patterns and temperature fluctuations are becoming increasingly unpredictable, the productivity of cultivated species must take into account the influence of the environment. However, identifying high-performing cuttings or cultivars for most crop improvement programs requires prior evaluation and characterization of their variability across a wide range of environmental conditions. The aims of this study is to evaluate the tuber productivity of seven orange-fleshed sweet potato varieties in three agro-ecological different sites (Bengou, Lougga tabla and Tahoua) in Niger. For this, a factorial block design with total randomization and three replications was implemented at the trial sites during the 2021 and 2022 rainy seasons. Two factors were investigated. The factor (variety) had seven (7) levels (var1 to var7), and the factor (site) had three (3) levels (S1, S2, and S3). The collected data were analyzed using Minitab.v18 and Rv4.3.1 softwares. Analysis of variance with effect of varieties and/or sites, and comparison of average performance of varieties through Fisher's test showed significant differences on the variables studied. The most productive varieties in terms of tuber yield were the BF59XCIP-4 variety, followed by TIO-JOE, AMELIA, CECILIA and APOMUDEN in the different trial sites. The lowest tuber yields were recorded with the varieties ININDA and SUMAIA. The variability is mainly attributable to differences in soil type and climatic conditions at the sites. The estimation of genetic parameters also highlighted a strong influence of environmental factors on trait expression, resulting in significant differences between phenotypic and genotypic coefficients of variation. Opportunities for varietal improvement can also be considered once the needs of producers and consumers are clearly identified, and varieties can be developed using the revolutionary genome editing technique (CRISPR-Cas9).