Root Formation by microshoots of Punus insititia L., rootstock GF 655/2 in an auxin-free medium

Abstract

Root formation Prunus insititia L., cv.GF 655/2 microshoots in an auxin-free medium (BM) after several subculture periods in a multiplication medium was studied. More roots were fomed in shoots when subeultured for 31 weeks in a multiplication medium (MM) than in those with only 2 subcultures. In the flrst group, roots started to emerge eight days after transfer of shoots to BM, while 24 days elapsed for those with only 2 periods in MM. All shoots rooted in the 31 group by day 16", but only 46.7% shoots of group 2 had roots at the end of the experiment (30 days). No differences were found in the number of roots but a larger root system was observed in the group of the 31 subcultures. This difference in rooting ability is attrihuted to partial rejuvenation caused by the long period spent in a cytokinin containing medium.