APPARENT REJUVENATION OF MATURE WILD CHERRY (PRUNUS-AVIUM L) DURING MICROPROPAGATION

Shoot tips from mature trees of the cherry rootstocks F12/1 (Prunus avium L.), Colt (P. avium x P. pseudocerasus) and an accession of P. avium from British woodland were placed onto a medium previously published for use with cv. F12/1. Reduction of pH to 5.0, a lower benzyladenine concentration and omission of GA3, low agar concentration and addition of phloroglucinol each increased shoot production on this culture medium. With cv. F12/1, number of shoots per culture and ability of shoots to produce adventitious roots increased with age of the culture line. Phloroglucinol added to the rooting medium significantly improved the proportion of shoots that rooted, but only during the first 700d of the culture lines. Phloroglucinol did not increase the number of roots per rooted shoot. The results are discussed as evidence for rejuvenation in vitro of mature P. avium shoots. Suggestions are made to improve the reporting of micropropagation data from shoot cultures derived from mature tissues and to explain variation in rooting results with phloroglucinol.