Phenotypic variability and racial classification of landraces of sorghum (Sorghum bicolor (L.) Moench) collected in the Northwestern Benin

Abstract

A morpho-botanical analysis of 76 sorghum accessions collected from the department of Donga, the northwestern part of Benin was carried out. An agro-morphological assessment of accessions was conducted based on 15 descriptors (10 quantitative traits and 5 qualitative traits). The experiment was laid at alpha lattice design with three repetitions. Four races (guinea, durra, caudatum and bicolor) were identified with high proportion of accessions of guinea race (86.84%) and low proportion of other races such as durra (5.26%), caudatum (2.63 %) and bicolor (1.32%). Kafir race was missed from the collection. The analysis of agro-morphological characters of accessions showed a significant phenotypic variability of sorghum local varieties kept and managed by farmers in Donga. The principal component analysis (PCA) performed on quantitative traits showed three axes accounted for nearly 70% of the total variation. The first axis represents plant height, diameter of third internodes, leaf length and leaf width of the third internodes; the second axis accounts for length of peduncle while the third one stands for the weight of 1,000 grains. On the basis of the quantitative and qualitative traits studied, ascending hierarchical classification according to Ward aggregation criteria differentiated four groups structured around key variables such as morpho-physiological characteristics of grains (color, size, degree of bitterness) and race.