Avaliação de clones de seringueira para a região noroeste do Estado de São Paulo

Abstract

As correlações genéticas e fenotípicas foram significativas e positivas entre todos os anos de produção. Para o vigor, a significância dos coeficientes de correlação genotípica e fenotípica diferiram na pré-sangria e na pós-sangria. Pelos valores de produção de borracha observados, os clones IRCA 111 e PB 235 são considerados favorá-veis à recomendação em pequena escala para a região de Votuporanga. Com base nos resultados obtidos, é possível realizar uma seleção precoce para o caráter de produtividade, usando-se os dados obtidos no primeiro ano de avaliação. Por causa das diferenças observadas entre os períodos de pré-sangria e pós-sangria, não é aconselhável realizar uma seleção precoce no período de pré-sangria, visando ao caráter de vigor. Palavras-chave: Evaluation of rubber-tree clones for the northwest region of São Paulo StateClones of rubber-tree [Hevea brasiliensis (Willd. ex Adr. de Juss.) Muell. Arg.] have achieved the highest yields of rubber in the State of São Paulo, Brazil. The objective of this study was to evaluate the yield and vigor of 14 rubber-tree clones cultivated in the region of Votuporanga and determine changes in the trend of annual correlation to examine the possibility of an early selection based on the studied characters. The yield of rubber was evaluated in the ½S d/4 5d/7 11m/y ET 2,5% tapping system, for a period of eight years. Vigor was also examined by measuring the girth for 16 years. The clones IRCA 111 and PB 235 showed the best yield performance. The best results of vigor, was achieves by clones IAC 15 and IAC 44. Genetic and phenotypic correlations were significant and positive for all production years. The significance of the genotypic and phenotypic correlation coefficients of vigor differed in the pre and post-tapping periods. Considering the rubber production found, the clones IRCA 111 and PB 235 can

Vigor assessment of juvenile rubber tree clones in Northwestern São Paulo State, Brazil

“…Therefore, the observed values indicate good experimental precision. The CV% values in the three experiments were similar to those observed for clones (Alem et al, 2015) and progenies (Verardi et al, 2012) of rubber trees of the same age.…”

“…The importance of assessing the vigor of rubber tree clones has been highlighted in several studies (Gonçalves et al, 2011;Gouvêa et al, 2012;Silva et al, 2014;Alem, et al, 2015). The genetic improvement program of the Agronomic Institute of Campinas (IAC) has evaluated elite clones of different clone series in distinct regions of São Paulo State.…”

Evaluation of Rubber Tree Clones Under Different Tapping Systems in Northwestern Paraná State, Brazil.

“…Even in the conditions of São Paulo plateau Silva et al 19 recorded that the system ½ S d/2 provided the greatest productivity of clone PB 235 and commented that this clone usually exhibit weak response to stimulation, but affirm that in the system ½ S d/7 ET 2.5% yield was superior to the ½ S d/4 ET 2.5% and recommend the system ½ S d /7 ET 2.5% due to absence of tapping panel dryness (TPD) disorder. Under the conditions of the Northwest of Paraná the clone PB 235 responded positively to stimulation in d/7 with a productivity of 1729 kgha -1 yr -1 , as well as the clone IRCA 111 that produced 1603 kgha -1 yr -1 (table 7), both recommended by Alem et al 1 for small-scale plantations in the São Paulo Northwest plateau. Silva et al 19 observed high incidence of TPD disorder in PB 260 clone in ½ S system d/3 ET 2.5% and suggest, to avoid this problem, the system ½ S d/5 ET 2.5% or ½ S d/7 ET 5%.…”

Selection strategies for growth characters and rubber yield in two populations of rubber trees in Brazil

“…There are studies that show that vigor (measured by stem perimeter) is considered the most important character to determine the precocity of the clone, allowing the rubber tree producer to have a faster return of its investment, with greater production in the first years of life, which confirm the efficiency of the early tests (Alem et al, 2015). Based on the high correlation between annual perimeter growth and rubber production and observed results, it is possible to predict that selection with this population is possible in young plants with maximum gain and in short time, minimizing the rubber production cycle (Gonçalves et al, 2006;Verardi et al, 2014).…”