Phenotypic traits of three local cassava (Manihot esculenta Crantz) genotypes cultivated by farmers in Rivers State, Nigeria

Abstract

The study aimed to elucidate the morphological and anatomical traits for varietal delimitation and identification of three local cassava (Manihot esculenta var. aguregbu, var. cagbo and var. ekagon) varieties cultivated by farmers in Obio Akpor local government area of Rivers state. Twenty (20) qualitative and six (6) quantitative traits from the descriptors for cassava germplasm was used for morpho-characterization. The results obtained revealed phenotypic similarity for 15 qualitative traits among the three varieties. Trait differences was observed in the petiole color (red and green), prominence of foliar scars, and shape of stem, level of branching, root shape and constrictions. The distance between leaf scars was classed as short for all varieties but the metric value ranged from 1.6 cm for ekagon to 4.0 cm for aguregbu and cagbo. Other quantitative variation observed include petiole length (11.1 to 15.0 cm) and storage root length which was classified as medium (≤30 cm) and long (>30 cm). The number of leaf lobes was seven for all varieties. The epidermal traits showed a uniseriate epidermis with hypostomatic distribution. The stem, petiole, and midrib anatomy was similar in terms of tissue type and arrangement. However, the number of vascular bundles in the petiole was more in aguregbu (10) than in cagbo (8) and ekagon (8). The variable traits identified in this study provide diagnostic features that could aid in the identification of the three cassava genotypes.