CARRY-OVER OF MORPHOLOGICAL AND BIOCHEMICAL CHARACTERISTICS ASSOCIATED WITH HYPERFLOWERING OF MICROPROPAGATED STRAWBERRIES

Strawberry plants issued from shoots raised after a high number of sub cultures (HNS) in vitro, which were previously characterized by an abn ormal hyperflowering process ex vitro, were multiplied conventionally through runners for 8 generations, and then meristem tips re-entered i n vitro for a low number of shoot subcultures (LNS). Such HNS-LNS vitr oplants flowered abnormally abundantly as compared with always convent ionally propagated N-LNS vitroplants, thus self-perpetuating a long te rm memory of an abnormal developmental pattern. The HNS-LNS hyperflowe ring vitroplants were also characterized by a carry-over of other biol ogical (reduced growth habit), morphological (reduced hairiness and de position of epicuticular wax, unifoliolate leaves prevailing) and bioc hemical (higher peroxidase activity) traits. They also proliferated in vitro at higher rates, which corresponded to higher endogenous levels of cytokinins and higher cytokinin/auxing ratios. Unifoliolate leaves and high cytokinin/auxin ratios are recognized criteria of rejuvenati on. These characteristics of I-INS strawberry vitroplants are carried- over in the next generations through heritable gene expression.