Bark Recovery of Rubber Clone PB 260 Through Application of NAA+, Kinetin and Oleo-chemicals.

Clone PB 260 firstly planted in 1975 and popular due to its exeellent vigor and produetivity during maturity (1.5-2 tonnes/ha10), the dense foliage redueed extensive weeding and is resistanee against major leaf diseases. The knowledge on the bark reeovery rate is very important to maintain high yield of latex produetion on rubber plantation. The study whieh was eondueted on the experimental farm of Rubber Research Institute, Sungei Putih, Deli Serdang, north Sumatra, Indonesia was aimed to obtain the optimum eombination eoneentration of growth regulators (NAA+ and kinetin) and various oleo-ehemieals to aeeelerate bark reeovery and response of bark reeovery rate for rubber elones PB 260. Faetorial randomized bloek design, whieh eonsists of two faetors, namely growth regulatoreon eentrations (N1=50 ppm NAA+ + 50 ppm kinetin; N2=100 ppm NAA+ + 50 ppm kinetin; N3=150 ppm NAA+ + 50 ppm kinetin) and oleo-ehemieals (O1=palmitie aeid; O2=oleie aeid and O3=stearie aeid) were used in this study. The parameters measured were the number of latex vessels, skin thiekness, suerose levels, thiol levels, inorganie phosphate level, latex yield and total solid eontent (TSC). The results showed that growth regulator eoneentrations signifieantly affeet the number of latex vessels but did not signifieantly affeet the skin thiekness, suerose levels, thiol levels, inorganie phosphate levels, latex yield and total solid eontent (TSC). The most optimum growth regulator eombination was N2 at various parameters observed. Oleo-ehemieals applieation showed signifieant effeet on the number oflatex vessels, skin thiekness and latex yield, but showed no signifieant effeet on levels of suerose, thiol levels, inorganie phosphate level and total solid eontent (TSC). Thus, applieation of growth regulator and oleo-ehemieals are benefieial to aeeelerate bark reeovery rate in order to maintain latex produetion on rubber plantation. [ABSTRACT FROM AUTHOR]