Transgenic central American, West African and Asian elite rice varieties resulting from particle bombardment of foreign DNA into mature seed-derived explants utilizing three different bombardment devices

We developed a novel system based on particle bombardment for the transfer of foreign genes into eight important rice varieties grown in Central Ameri ca, West Africa and Asia. Novel features of this improved protocol, which w e believe will replace alternative systems currently utilizing immature emb ryos, embryogenic cell lines or suspension cultures include: (a) bombardmen t of target tissue 5 d after seed germination; (b) no requirement to select for embryogenic callus prior to bombardment; (c) high transformation frequ encies (up to 14%); (d) ability to recover transgenic material at similar f requencies irrespective of bombardment devices used. Southern blot analysis and enzymatic assays in primary transformants and progeny confirmed the st able integration and expression of introduced transgenes in all engineered cultivars. (C) 1998 Annals of Botany Company.