Development of Insect-tolerant Plants with Somaclonal Variation

Abstract

The potential value of somaclonal variation for economically important plants is well-documented. The process of somaclonal variation can arise from a controlled or a random source of variation. Variability can be obtained by applying cellular pressures and selection. Valuable resistance to diseases and nematodes has already been accomplished with somaclonal variation; now, plant tolerance to pests has been realized. Tetranychus urticae, the two-spotted spidermite, and Trialeurodes vaporariorum, the greenhouse whitefly, were disinfected and introduced to aseptic shoot cultures of Torenia fournieri. These pests were allowed to feed until such time that their populations decreased due to the absence of food. The plant cells that remained after feeding were induced to form adventitious shoots and plantlets. These regenerated plantlets were acclimated to greenhouse conditions and evaluated for tolerance to the pest to which they were subjected in vitro. Highly significant differences were found in somaclones for both the two-spotted spidermite and greenhouse whitefly when compared to control plants. A wide range of variability was observed among the somaclonal population. There were significantly fewer mite eggs laid on plants regenerated from in vitro cultures screened with two-spotted spidermites than on seed-sown controls. Regenerants from cultures screened with whiteflies in vitro had fewer eggs, immatures and live adults than controls. The potential for somaclonal variation to be used as a method to develop insect resistant plants will be discussed.