Performance of new Hevea clones from IAC 400 series

Abstract

The Hevea breeding program of Instituto Agronômico de Campinas (IAC) has completed clonal evaluation on the following series: IAC 100, IAC 200 and IAC 300. The performance of 22 clones of Hevea brasiliensis (Willd. ex Adr. de Juss.) Muell.-Arg., evolved at IAC, over a period of eleven years was evaluated in the Western Central part of the São Paulo State, Brazil. Among these 22 new clones, six were intraspecific hybrid clones (IAC 400, IAC 404, IAC 405, IAC 406, IAC 410, IAC 412) and the remaining are primary those resulted from selected ortets within half-sib progenies. An old popular clone RRIM 600, of Malaysian origin, was used as the control. The trial was laid out in a randomized block design with three replications. Yield performance over a period of four years, mean girth at the 11 th year, girth increment before tapping and on tapping, thermal property of natural rubber produced, bark thickness, number of latex vessel rows in seven year virgin bark, percentage incidence of tapping panel dryness, wind damage and diseases like leaf and panel anthracnose have been observed. Sixty one percent of the clones were superior in relation to the control for yield. The clone IAC 400 recorded the highest yield (97.40 g tree -1 tap -1 ) over four years of tapping, followed by IAC 411 (78.87 tree -1 tap -1 ), whereas the control clone RRIM 600 recorded 50.86 g tree -1 tap -1. All selected clones were vigorous in growth. Girth increment of these clones was average to above average. Except for IAC 423, other clones had thick virgin bark at opening ranging from 4.84 mm for IAC 401 to 6.38 mm for IAC 416. The natural rubbers from IAC clones have shown good thermal stability up to 300 o C and no differences in the thermal behavior among rubber from clones of the IAC series and the clone RRIM 600 were found in inert atmosphere. Braz.), v.64, n.3, p.241-248,

Assessment of rubber tree panels under crowns resistant to South American leaf blight

“…These results are similar to those obtained by Gonçalves et al (2001a), Virgens Filho et al (2001, and Gonçalves et al (2007) per year, even though they produced good yield under other edaphoclimatic conditions (Pereira et al, 1999;Gonçalves et al, 2001b;Silva et al, 2010). The poor results found for these clones do not prevent their use in future studies carried out in other regions.…”

“…to obtain crown clones resistant to SALB has produced extremely positive results. The most promising clones achieved dry rubber yield above 1,000 kg ha -1 per year in the initial two years of tapping , similar to the results obtained in other rubber regions in Brazil (Gonçalves et al, 2001a;Virgens Filho et al, 2001;Gonçalves et al, 2007;Silva et al, 2010).…”

Clones de copa de seringueira resistentes ao mal-das-folhas para o cultivo na Amazônia tropical úmida

“…Esses valores são semelhantes aos das avaliações feitas por Gonçalves et al (2007;) e Virgens Filho et al (2001 com clones cultivados no estado de São Paulo. Em contrapartida, os clones CPAA C 18 e CPAA C 33 apresentaram baixo desempenho, com produtividade, na média, inferior a 1.000 kg ha -1 ano -1 de borracha seca, indicando baixo potencial, não sendo eles indicados para o cultivo na região (Tabela 2).…”

Performance and genetic assessment of rubber tree clones in Southern Thailand

“…The SK1 clone had higher yield and growth in terms of latex yield, girth increment and renewed bark thickness. Thick bark is a very important characteristic, because it minimizes the wounding incidences that are known to affect productivity after tapping (Gonçalves et al, 2007). Even the single clonal variety RRIM 600 had different latex yields depending on the location.…”