PROPAGATIVE TECHNIQUES ON SOFTWOOD CUTTING FOR DOUBLE HYBRIDS OF SECTION LEUCE DULY

The propagation of (P.tomentosa×P.bolleana)×P.canescens was researched by means of the softwood cutting and the micro-softwood cutting (single-internode and single-leaf softwood cutting) in the deep pit, which was 100 cm in width, 700 cm in lenghth, its south side and north one were 150cm and 180cm in depth respectively under the ground.In the softwood cutting, the desirable cutting medium was the uniform mixture of sand and surface soil (1:1);the sucker softwood cuttings from the stubs had obviously higher rooting percentages than those from 3-year-old trees;the better rooting hormone (quick-dipping) was the Rooting Powder (ABT No.1) 500×10^-6 or IBA500×10^-6 +NAA500×10^-6.In micro-softwood cutting, the cuttings that remained 4cm 2area of leaf had the better rooting percentages than others;the best cutting medium was also the mixture of sand and soil(1:1);the better rooting hormone (quick-dipping) was IBA500×10^-6 +NAA500×10^-6.