Use of morphometric parameters for tracking ovule and microspore evolution in grapevine (Vitis vinifera L., cv. "Aragonez") and evaluation of their potential to improve in vitro somatic embryogenesis efficiency from gametophyte tissues

Somatic embryogenesis induction from in vitro cultured stamens and carpels is highly dependent on expiants' inoculation at specific developmental stages. To establish good correlations between measurable morpho- metric parameters of flowers or flower buds and develop- mental stages of micro- and macrosporogenesis, this procedure is the easiest way to simplify the in vitro culture procedures. These correlations were established here for the most important Iberian grapevine cultivar, the "Aragonez", named "Tempranillo" in Spain and "Tinta Roriz" in the north of Portugal, and were based in floral buds and anther measurements. The anther length, with a correlation coefficient of 0.90, proved to be the best morphometric parameter to follow microsporogenesis evolution. A corre- lation between micro- and macrosporogenesis evolutionary stages was also positively established, allowing the use of