Early Growth and Yield Performance at Nursery Stage of a Set of Brazilian Wild Hevea Germplasm of IRRDB Collection

Abstract

A set of 55 wild Hevea brasilensis accessions from three provenances of Brazil viz., Acre (AC), Rondonia (RO) and Mato Grosso (MT), along with two popularly cultivated clones RRII 105 and RRIM 600 were evaluated for their early growth and yield performance in the first six years of growth in a nursery in the traditional rubber growing region of Kerala state, India. Relatively high clonal variability was observed for yield, while variation for girth, girth increment, single leaf area, total number of laticifer rows, diameter of latex vessels, bark thickness and crotch height ranged from medium to low. The yield ranged from 0.04 g/t/t (RO 5358) to 11.19 g/t/t (RO 5018), bark thickness from 1 mm (AC 5896) to 5.30 mm (MT 4771), total number of laticifer rows from 3 (MT 5824) to 10.67 (RO 2841) and diameter of latex vessels from 10.69 μm (AC 5487) to 21.66 μm (MT 4762). Girth ranged from 10.75 cm (AC 5896) to 35.60 cm (RO 5432) in the 6th year, while girth increment over three years ranged from 0.50 cm/year (AC 5466) to 5.47 cm/year (RO 5432), crotch height ranged from 1.88 m (RO 5364) to 5.14 m (MT 4690) and single leaf area from 37.51 cm2 (RO 5318) to 150.40 cm2 (RO 5365). The accessions were ranked using all the above parameters except single leaf area, for overall performance. Rank sum values ranged from 30 to 340 with a general mean of 194.33. Based on this study, the top 20% of the potential accessions showing early growth vigour and yield were identified which could be of use in broadening the narrow genetic base of currently cultivated genotypes and for future crop improvement programmes.