IN-VITRO CULTURE OF WHEAT AND GENETIC-TRANSFORMATION - RETROSPECT ANDPROSPECT

This review focuses on the improvement of wheat (Triticum aestivum L.) via tissue and cell culture and its use in gene transfer techniques. Success of the latter critically depends on the ability to regenerate plants from cells or tissues cultured in vitro. Hence, we have devoted attention to the attempts made so far in obtaining regenerants from d iverse explants. Although it is known that immature embryos are the be st source for initiating morphogenic cultures, basic information relat ed to the process of differentiation can also be gained by studying le ss responding tissues. The opportunity provided by anther and microspo re culture in wheat improvement and the progress made is also presente d.To enhance tissue culture responses, identification of chromosomes, gene loci, and genes is of cardinal importance. We have also surveyed the progress made in this regard by conventional but incisive plant-br eeding techniques. Gene rearrangements in tissue culture leading to th e appearance of somaclonal or gametoclonal variation are of interest i n selection of useful cell lines. The last part of the review is devot ed to work done on transient gene expression and transformation with e mphasis on recent developments.