| Rapid method of transferring alien genetic variation
to wheat by substitution and recombination J.G. BHOWAL Division of Genetics, Indian Agricultural Research Institute, New Delhi-110012, India The related genera of bread wheat (T. sestivum L.) such as Aegilops, Agropyron and Secale have many genetic attributes of agricultural potential, specially disease resistance. A few method, such as, amphidiploidy, alien addition, induced translocation, alien recombination and alien substitution have been employed to introduce genetic variation to wheat. Amongst these there are rare reports of application of last two methods in India and many other countries excepting a few European and North American countries. Long procedure involved in these two methods and also non-availability of monosomic lines in suitable background may be limiting factors. In this Institute we are following two modified methods for alien chromosome substitution and alien recombination. The methods essentially involve the introduction of alien material in partially developed monosomic lines instead of waiting till the monosomic lines are fully developed in a variety. By following these methods, we expect to cut short the standard long procedures substantially. It will also be possible to develop the alien substitution and recombination lines in any sutiable background desired. The methods are birefly described and schematically presented (Figs. 1 & 2). I. Alien recombination 1. Cross the recurrent variety with mono-5B of Chinese Spring. 2. Identify F1 mono-5B and cross with the desired alien species (from Aegilops, Agropyron, Secale etc.). 3. Select 5B- deficient 27-chromosome hybrid. In absence of chromosome 5B pairing between wheat and alien chromosomes would take place leading to recombination. Backcross with the recurrent variety for at least three generations. 4. Self the last back-cross progeny, Select the fertile 2n=42 chromosomes derivatives. The selfed progeny is expected to have many alien recombinants in the recurrent variety. |
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