Pd. Goncalves et al., COMPONENTS OF VARIANCE AND INTERACTION BETWEEN GENOTYPE AND ENVIRONMENT FOR ANNUAL GIRTH INCREMENT IN RUBBER TREE, Pesquisa agropecuaria brasileira (1977), 33(8), 1998, pp. 1329-1337
To determine the nature and extent of genetical and environmental cont
rol of vigour through annual girth increment in rubber trees [Hevea br
asiliensis (Willd, ex Adr. de Juss.) Muell. Arg.], seven clones were s
tudied in a replicated trial in Sao Paulo State at four different loca
tions. The clones represented a range of imported germoplasm while the
locations were selected to represent a range of rubber growing areas.
Trees were studied for annual girth increment over five years before
the initiation of tapping for latex. The results of the analyses show
a consistent decrease in genetic component over the five years from 10
per cent to 0.5 per cent with a corresponding increase in the effect
of environment (19.0 per cent to 93.0 per cent). The genotype x enviro
nment effects from combined analysis were significant for three factor
analysis of variance. Genetic correlations between locations for annu
al girth increment revealed a consistent positive and significant corr
elation between Mococa and Matao in the fifth year (r(g) = 0.7128), Ri
beirao Preto and Matao in the fifth year (r(g) = 0.7113) and Ribeirao
Preto and Presidente Prudente in the fourth year (r(g) = 0.9367). The
implications of these findings in selection of rubber for annual girth
increment trait are discussed.