AGROMORPHOLOGICAL CHARACTERIZATION AND EVALUATION OF OKRA [Abelmoschus esculentus (L.) Moench] GENOTYPES AT MELKASSA, CENTERAL ETHIOPIA

Abstract

Okra [Abelmoschus esculentus (L). Moench] is one of indigenous and endemic genetic resource of Ethiopia as well as Benishangul Gumuz. However, only few studies were carried out to assess its diversity and performance throughout the country and specifically no research conducted to assess diversity of okra within regional state. Therefore, this study was conducted with the objective to assessing the genetic divergence and estimate the genetic variability components in okra genotypes collected from regional state, and to determine the association of traits and the direct and indirect effects of traits on fruit yield. A total of 36 genotypes of which 33 okra genotypes were collected from different areas of Benishangul Gumuz Regional State, 3(three) checks, of 2 introduced and 1(one) released were evaluated for 27 quantitative and 13 qualitative traits at MARC in 2018/19 using simple lattice design (6 x 6). The results from analysis of variance revealed the presence of significant variation for all quantitative traits except 3 traits. Moreover, the variation of genotypes for fruit yield per hectare ranged from 9.44 to 32.88ton/ha-1 with mean 19.59ton/ha-1 for genotypes 29620 and 29618, respectively. Most of genotypes had high mean performance as compared to checks for majority of traits. The majority of genotypes had almost desirable qualitative traits such as color of fruit, pubescence and general growth habits. The genotypic (GCV) and phenotypic (PCV) coefficient of variation were in range of 6.3 to 54.19% and 9.19 to 55.51%, respectively. Heritability in broad sense (H2) and genetic advance as percent of mean (GAM) had ranged from 43.46 to 97.34% and 9.16 to 109.14%, respectively. The variability components (GCV, PCV, H2 and GAM) were high for all traits except few traits like days to 90% maturity, hundred seed weight low in PCV and GCV. Number of ridge and hundred seed weight showed moderate H2 whereas days to 90% maturity, number of ridge and percentage of mucilage content had moderate GAM and low for hundred seed weight. It is found that number of primary branches, fruit diameter, number of tender fruit per plant, seed yield, and number of harvests are correlated to fruit yield at genotypic and phenotypic levels, whereas average fruit weight was correlated at phenotypic level. Traits like number of primary branches, seed yield and average fruit weight had positive and significantly high direct effect on fruit yield. Therefore, they should be considered during selection for fruit yield improvement. The genetic distance of genotypes ranged from 2.83 to 12.24 with mean, standard deviation and coefficient of variation 6.73, 1.63 and 24.18(%), respectively. All the 36 genotypes clustered in 13 distinct cluster consisting 11 (30.56%) in cluster I to seven cluster in which genotypes are solitary clustered. Among cluster, cluster VII had the highest fruit yield by leading other seven cluster greater than overall cluster means. Principal component analysis revealed four principal components (PC1 to PC4) with eigenvalues ranged from 1.83 to 7.58 which accounted for a total of 71.34% cumulative contributions. The result observed in these study was the presence of a wide genetic variation among genotypes collected from Benishangul Gumuz Regional State.