VARIABILITY OF THE STRUCTURAL CHARACTERS OF THE BARK IN THE LATICIFEROUS SYSTEM OF THE JUVENILE HEVEA SEEDLINGS

Studies of variability and repeatability for characters of the laticif erous system of the bark in 76 three-year old seedlings of rubber tree [Hevea brasiliensis (Willd. ex. Adr. de Juss.) Muell Arg.] were under taken. The studied characters were bark thickness (EC) total number of latex vessel rings (NA), diameter of latex vessel rings (DIA), densit y of latex vessels per 5 mm per ring averaged over all rings (DD) and average distance between consecutive latex vessel rings (DMV). Based o n the analysis of variance, coefficient of repeatability and genetic g ains were estimated for each character for each two, three and four di fferent height samples taken from the stem of each seedling. The highe st average repeatability values were ($) over cap p = 0,73 and ($) ove r cap p = 0,93 for DMV and EC, respectively. These highest-genetic adv ances were obtained for EC and NA with four (Gs = 22,51%) and five (Gs = 11,35%) samples, respectively. Based on the results it was conclude d that repeatability and the high percentual of genetic gain obtained of three bark samples from different heights showed a better progress in the selection.