A progeny test of Bombacopsis quinata (Saqui-saqui) of about 26 years of age without thinning

By the contineous help of Prof. W. LANGNER the senior author became the possibility to work between 1961 to 1963 and 1968 and 1971 in the Institute of Silviculture of the Faculty of Forestry, Institute of Silviculture in the University of the Andes in Merida/Venezuela. Results of this stay are evident in the foundation of a section for seed science and forest genetics and scientifically amongst others in the vegetative propagation of Saqui-saqui by branch and stem sets and grafts, which flowered and bore fruits within mostly 1 to 2 years after plantation. As a consequence in various countries of the natural distribution of the species in question clonal gardens as genetic resources and seed orchards could be established preferably with branch and stem sets. The problemless planting and treatment of the species in plantations made both - the clonal gardens and seed orchards - to a large field of flowering research in Colombia and Venezuela and to an important fountain ofseed production for large scale plantations of about 10 000 ha especially in Colombia and Costa Rica. First crosses and open pollinated progenies made in Venezuela between 1968 and 1971 were cultivated in the institute's nursery in El Irel, and established as progeny test in Fl Caimital, the University's experimental forest, Barinas state in 1970. That is a site in the Eastern Llanos near the Yuca River with a pronounced dry period between November and March (min. January/February), a precipitation of 1500 mm (max. June/August) and an annual mean temperature of 26 degrees C. According to HOLDRIDGE Fl Caimital is a tropical dry forest. Eighty to 135 species/ha, an abundant number of palm trees of only a few species are growing in this forest of gallery. According to the grade of exploitation it is a secondary forest with few precious species as Mahagony and Saqui-saqui. The soils of the 3 test sites are sandy to clay differentiated in higher and lower parts of the ground, the ''bancos'' and ''bajios'', and sporadic inundation for hours or days. The better test site seemed to be the river side (''agrobancor''), followed by the ''banco arenoso'' and the ''banco negro'' with higher content of clay and the longer inundations. Theseedlings were planted in June/July 1970 during the raining season without any fertilization but the refined soil of each of the holes of 40 cm of depth and 30 cm x 30 cm of width. The distance between plants were 3.5 m x 2.5 m (banco arenoso, banco negro) and 5 m x 5 m (agrobanco) respectively. The design were disbalanced complete randomized blacks with plots of 4 plants. Between 1970 to 1982 the trial was cleaned 2 times a year by machete and after that time sporadically within the rows till 1995.In 1996 the trial was completely cleaned from weed, climbers and other tree species. No thinning took place within 26 years.