DIVERSITY AND STABILITY OF GROWTH AND YIELD TRAITS OF SOME COCOA GENOTYPES

Abstract

The agronomic and yield related characteristics of twenty Cocoa genotypes established and laid out in randomized complete block design (RCBD) with six replications were studied for two years at the Cocoa Research Institute of Nigeria (CRIN), Ibadan, Nigeria to understand their diversity and stability. Data were collected quarterly in each year on tree circumference (TC), jorquette height (JH), number of ripe fruits (NRF) and number of wilted fruits (NWF). The data were subjected to analysis of variance (ANOVA), correlation and clustering using (SAS), version 9.2, (SAS, 2007). The genotypes differed significantly (P≤0.05) for the four traits in each year and for the two years. Genotype by quarter interaction was significant (P≤0.05) for NRF and NWF in 2013 and for the two years. Year by quarter interaction was significant (P≤0.001). The total variation among the twenty genotypes were explained by the first three principal component axes at 97.7%, 93.9% and 97.3% in 2012, 2013 and combined years. Three clusters were generated in the clustering pattern in each case. T65/7xT57/22 gave the highest pod yield (25.16). Pod yield stability estimate by Wricke ecovalence of T65/7xT57/22 was 100.788. The genotype ranked poorly in terms of stability. However, T65/7xN38, T12/11xN38, PA150xT60/887, T82/27xT12/11 and T65/7xT53/8 were identified in this study as the genotypes with high pod productivity and with good genetic stability.