GENETIC DIVERSITY AND CHARACTER CORRELATION STUDIES AMONG SELECTED GENOTYPES OF OKRA, Abelmoschusesculentus(LINN) MOENCH ACROSS TWO ENVIRONMENTS

Abstract

ABSTRACT Okra (Abelmoschus esculentus L. Moench) has caught global attention in terms of nutritional and medicinal properties. However, narrow genetic base of the crop impedes its improvement programme. To this end, genetic diversity and character correlation studies is inevitable. The experiment was designed on 35 okra genotypes collected from National Centre for Genetic Resources and Biotechnology (NACGRAB), Ibadan to (i) determine the diversity among selected okra genotypes (ii) assess characters association and (iii) identify high-yielding genotypes. The research was carried out at Teaching and Research Farm of Federal University of Agriculture Abeokuta (70 15’ N 30 44’E) and the Field Genebank of NACGRAB, Ibadan (70 25’ N 30 51’E)between July and November, 2022. Data collected on 19 agro-morphological traits were analyzed using SAS 1999 package. Analysis of variance (ANOVA) was used to detect significant differences among the 35 genotypes based on 19 agro-morphological traits. Significant means were separated using Duncan’s Multiple Range Test. Principal Component Analysis (PCA) was used to determine the contribution of each trait to the total variation observed. Broad sense heritability (H2) and Genetic Advance (GA) were also determined for each of those traits. Fastclus analysis was used for partitioning clustering on similarities, and variation within cluster. ANOVA showed highly significant (p<0.01) genotype effect on days to 50% flowering (DAF50), days to first fruiting (DFFR), number of pods (NP), seed yield per plot (SYP) while interaction effect was highly significant (p<0.01) in DFFR, NP, SYP, 100 seed weight (100SW). PCA showed 7 principal components with eigen values > 1 with PC 1 accounting for highest proportion variation of 23.00%, followed by PC 2 (9.00%) and PC 7 (5.12%) with cumulative variation of 65.28%. Broad-sense Heritability ranged from 0.02 for pod width (PDW) to 0.14 for 100SW while GA showed lowest value (2.94) for PDW and highest value (228.25) for SYP. Genotypic correlation coefficient showed that seed yield was highly and positively significant with days to emergence (DTE) (r = 1.00**), plant height (PH) (r = 1.00**), PDW (r = 0.44**) and negative correlation with day to first flowering (DFFL) (r = 1.00**), DAF50 (r = 0.14**), DFFR (r = 0.02**). Phenotypic correlation coefficient indicated that seed yield exhibited significant positive correlation with most traits. Fastclus analysis produced 7 clusters on similarities; Cluster 1 (11 genotypes), Cluster 2 (8 genotypes), Cluster 3 (3 genotypes), Cluster 4 (3 genotypes), Cluster 5 (6 genotypes), Cluster 6 (3 genotypes) and Cluster 7 (1 genotype). It was concluded there is diversity among the 35 okra genotypes with significant traits correlation among the characters considered. 1NGB0040, NGB00346, NGB00333, NGB00469, NGB00349, NGB02456, NGB00343, NGB00331, NGB02433, NGB00464, NGB00297 and NGB00298 are identified as high yielding, and recommended for heterosis breeding.