Determination of Variation in Morphology and Leaf Bitterness in Spider Plant (Gynandropsis Gynandra (L.) Briq. Across Six Agroecological Zones in Kenya

Abstract

Gynandropsis gynandra (L.) Briq. also referred to as spider plant (English), is an important leafy vegetable in the diets of rural and urban communities in Kenya. Young leaves, stems and or flowers are consumed as vegetable relish and are reported to be rich in vitamins (A and C), minerals (calcium and iron) and other health promoting compounds. Spider plant is adapted to various ecological habitats and hence exhibits variation in morphology and leaf bitterness. This variation has not been studied systematically in Kenya while the bitter taste in some spider plant varieties hampers its wider consumption by certain community groups such as youth and children. The aim of this study was to evaluate variation in morphology and leaf bitterness in spider plant from six (6) agro-ecological zones and establish whether leaf bitterness is associated with morphological traits. Purposive sampling method was used to sample spider plants that were used for morphological characterization in 2017. A total number of seventeen (17) sites within the six (6) agro-ecological zones (AEZs) in Kenya namely, the upper and lower highlands, upper and lower midlands, inland and coastal lowlands were sampled. Morphological characterization was based on seventeen (17) qualitative (observational and sensory) and nine (9) quantitative traits identified by IPGRI. Leaves of the mature plants were subjected to organoleptic testing to evaluate the variation in leaf bitterness. Qualitative data was analyzed using descriptive and inferential statistics such as percentages, while the quantitative traits were subjected to statistical measures of means. Pearson correlation analysis was performed to find out the relationships between level of leaf bitterness and qualitative traits; colour of main stem, stem pubescence, colour of leaf blade and leaf waxiness. Results showed that there was morphological variation in all the traits studied, eight (8) of which recorded significant differences. There was also variation in leaf bitterness, with the bitterest plants scoring 4.2 in the lower midlands and 4.0 in coastal lowlands while the least bitter ones scoring 1.0 in the upper highlands. The colour of the leaf blade was the only morphological trait associated with leaf bitterness. Cluster analysis based on the level of leaf bitterness divided the Gynandropsis gynandra specimens into two (2) major groups and eight subgroups. The study concluded that agro-ecology variation (mostly associated with variation in temperature and moisture levels) had a significant effect on the morphology and level of bitterness of spider plant.