Early bud emergence and growth of rubber (<i>Hevea brasiliensis</i> Muell Arg.) budded stumps as influenced by cut-back height and induction methods

Abstract

Early bud emergence of rubber (Hevea brasiliensis Muell Arg.) guarantees uniform plant growth leading to vigorous plants, escape from diseases, saves time, resources and increase in production. The field experiment carried out at Rubber Research Institute of Nigeria, Akwete Substation, Abia State, Nigeria was aimed at determining the interactive effect of cut-back height and bud induction methods on bud emergence and the growth of Hevea-budded stumps. The trial was laid out in a 3 x 3 factorial arrangement using the randomised complete block design with three replications. The factors were cut-back height (≥ 7.0 ≤ 7.5 cm, ≥ 7.5 ≤ 8.0 cm and ≥ 8.0 ≤ 8.5 cm) and induction methods (control, notching and ringing). Plant traits assessed were days to first and 50 per cent bud emergence, percentage survival at 3 months after transplanting (MAT), shoot length, stem girth, leaf stalk length, number of leaves/plant, leaf area and sturdiness quotient at 2 and 5 MAT. Results showed that induction method significantly affected the tested traits except days to first bud emergence, leaf area and stem girth at 5 MAT, percentage survival at 3 MAT and sturdiness quotient at 2 MAT. Cut-back height significantly affected stem girth, number of leaves/plant, leaf stalk length, leaf area and sturdiness quotient. The interaction effect of cut-back height and induction method was significant for shoot length, number of leaves/plant, leaf area and leaf stalk length. Correlation analysis indicated that number of leaves per plant exhibited significant (p ≤ 0.05) and positive association with leaf stalk length with correlation coefficient of r = 0.72 and leaf area (r = 0.57) at 2 MAT as well as with shoot length (r = 0.83) at 5 MAT, which implied increased photosynthetic ability and high latex production. The other variables exhibited different degrees of correlation amongst themselves.