Agromorphological description and determination of the antioxidant potential of the underutilized and newly introduced varieties of maize cassava, cowpea and hot pepper in the Maritime-East region of Togo

Abstract

In Togo, the importance given to local varieties of plants is decreasing due to the gradual change in cropping patterns and eating habits. These varieties are threatened with extinction for the benefit of introduced varieties. For sustainable management of these local varieties, a morphological characterization is necessary. Little research has been carried out on the agromorphological characterization of local varieties of the main crops (maize, cassava, cowpea and pepper) of the Maritime-East region of Togo, as well as their nutritional values. This study aims to undertake inventory of the local varieties, to determine their degree of threat, and to compare the antioxidant potential of the highly endangered local varieties and those introduced (corn, cassava, cowpeas and pepper). To achieve these objectives, ethnobotanical surveys were carried out in 25 villages, with 126 resource persons. The villages were chosen in order to have a homogeneous distribution and a total coverage of the ethnic groups. As for the resource persons, they were chosen by agreement of the local authorities who have taken note of the questionnaire. Local varieties have been differentiated by the agromorphological descriptors used for this purpose. The degree of extinction threat was determined by the "local varieties x localities" matrix. The principal component analysis made it possible to evaluate the structuring of local diversity on the basis of agromorphological criteria. The 44 local varieties are discriminated in four categories. The category of very threatened local varieties; threatened; fairly threatened and less threatened contain respectively four, six, eighteen and sixteen local varieties. The 2,2-diphenyl-1-picrylhydrazyl reduction test is used to determine the antioxidant potential of the highly endangered local varieties (Ayidzin, Adibolo, Katowali and Blikouhe) and those introduced. The highly endangered local varieties all have significant antioxidant potential compared to the introduced varieties. The ratio was as follows: 1.4 for pepper; 2.6 for maize; 5.2 for cassava and 6.4 for cowpea. These data will, thus, make possible the valorization of this agrobiodiversity with aims to safeguarding. The use of local varieties will thus help to combat malnutrition and promote sustainable management of these plant genetic resources. A deep phytochemical screening should be necessary to identify the molecules responsible for differences in antioxidant potential.