CHARACTERIZATION (MORPHOLOGICAL AND MOLECULAR) AND SENSORY EVALUATION OF IMPROVED LABLAB GENOTYPES

Abstract

Lablab purpureus is a multipurpose legume mainly grown by subsistence farmers for pulse, forage and vegetable. Despite these diverse uses that can be combined successfully under various agronomic conditions, the bean has not been extensively exploited. Dolichos production in Kenya is constrained by low yielding varieties, pests, poor growing techniques and varieties with non-preferred taste and flavor. This study was initiated to access the diversity, cooking time and organoleptic traits of six Dolichos genotypes, ( G2, B1, M5, LG1, W7 and G2), that had been bred at the University of Eldoret and two checks (Local Variety and DL1002) across three sites. The genotypes were characterized using morphological and molecular markers. Morphological characterization was done in three sites; University of Eldoret‟s farm, Njoro and in Mabanga FTC-Bungoma County. Morphological traits (qualitative and quantitative) were characterized using the descriptors of genus Lablab. Molecular characterization was done at the KEPHIS- Muguga laboratory, using ten SSR markers that are specific for Dolichos. Cooking time and organoleptic studies were carried out on-farm in Meru County, Ruiri sub location using an organized farmer group (Ruiri farmers group) that comprised of ten panelists (seven women and three men). Results from morphological characterization demonstrated a high variation for both qualitative and quantitative traits evaluated. Most of the quantitative traits were highly significant at 99.999% or (P≤ 0.001), except for number of racemes per plant and number of seeds per pod which were significant at 99.99% or (P≤ 0.01) and 99.95% or (P≤ 0.05) respectively. Microsatellite analysis produced six polymorphic primers mapping an average of 3.17 alleles per locus. There was a significant difference (P ≤ 0.001) among the six improved genotypes and the two checks in terms of cooking time and sensory attributes evaluated. Cooking time ranged from 87-159 minutes, with genotype M5 taking the shortest time and Local variety taking the longest time to cook respectively. In terms of overall acceptability, genotypes G2, G1, M5 and B1 were highly rated because of their short cooking time and good organoleptic attributes. High variability among the genotypes evaluated could be exploited even further in breeding programs to produce genotypes that take even less time to cook and with even better organoleptic characters for easy adoption by farmers.