Avaliação preliminar do desempenho de clones de seringueira (Hevea spp.) na região de Goiânia

Abstract

This work was carried out from 1991 to 1996, in the EMATER Experimental Station, which is located 20 km far from Goiânia, 16o 40’ of south latitude, 49o 15’ of longitude (W.Grw.) and 741 m of altitude. The experimental design was in rondomised complete blocks, with 3 replications. It was tested the clones IAC 15, RRIM 600, IAN 873, IAN 3044, IAN 2880, IAN 2878, IAN 3997, Fx 985, Fx 2261, Fx 3846 and evaluated the following characters: annual stem girth; bark thickness; percentage of branched threes for natural crown formation in the second year; rubber yield potential in the fifth year by the modified Hamaker, Morris & Man test tapping (Alves, 1985), trunk type; crown shape and its relative size and density; percentage of tappable plants; insects and diseases incidences and wind damages. The results showed that: RRIM 600, IAC 15, IAN 2880, IAN 2878 and IAN 3044 are the most promising clones for the Goiânia region; clones with both higher percentage of branched threes in the second year and higher crown size generally present higher values of stem girth, bark thickness and percentage of tappable plants; the crown shape is oval in the clone RRIM 600, but round in the other clones; the crown density is higher in the clones IAC 15, IAN 3044, IAN 2880 and IAN 2878, medium in the clones RRIM 600 and Fx 985, and lower in the other clones; the trunck is distorted in the clones IAN 873, Fx 2261 and Fx 3846, but erect in the other clones; the clones IAN 2880 and IAN 2878 are not preferred by Leptopharsa heveae Drake & Poor (Hemíptera, Tingitidae) and should be more investigated about this character; the clones IAN 2880, IAN 2878, RRIM 600 and IAN 873 are susceptible to wind damage; the clones IAC 15 and Fx 3846 are susceptible to die-back caused by the fungus Lasiodiplodia theobromae (Pat.) Griff & Maubl.. This evaluation is still preliminary and should continue for at least four years under normal tapping in order to obtain more accurate results.