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The programme examines some aspects of the evolution of modern disease resistant varieties of bread wheat.
Metadata describing this Open University video programme
Module code and title: S299, Genetics
Item code: S299; 10
First transmission date: 05-07-1976
Published: 1976
Rights Statement:
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Duration: 00:24:19
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Producer: Jean Nunn
Contributors: Denis Gartside; Colin Law
Publisher: BBC Open University
Keyword(s): Chromosomes; Colchicene; Compain; Disease resistant strains; Genetic variation; Hybrids; Pairing; Sterility
Footage description: Colin Law, at the Plant Breeding Institute, Cambridge, introduces the programme. Denis Gartside, voice over animation, explains the ancestry of the hexaploid bread wheat which was developed from three diploid species each having 14 chromosomes. Colin Law demonstrates a technique for studying the ancestry of wheat. He prepares a slide of grass anthers and examines them under the microscope. Law next points out some of the diploid relatives of wheat at the Plant Breeding Institute. He compares a spike of this goat grass with a spike of wheat. Law goes on to demonstrate a method of hybridising wheat with goat grasses. Law looks at micrographs of the chromosomes of two such crosses. One of these exhibits pairing and Law concludes that this particular grass is the donor of one of the genomes of wheat. Denis Gartside recaps the experiment. Law, looking at several wheat plants, summarises the evolution of the tetraploid wheat, triticium durum. Law goes on to summarise the evolution of hexaploid wheat leading to the bread wheat, triticum aestivum. Law examines a wheat plant infested with yellow rust. He compares this with a grass Aegilops comosa which is free of the disease. Law speculates on the possibility of transferring the resistant genome of this grass to wheat. Law talks through the steps taken to hybridise a rust resistant wheat. He points out how the problem of sterile hybrids is overcome by use of a drug, Colchicene, which induces chromosome number doubling. He goes on to explain how the disadvantageous genes still left in the hybrid are eliminated. Denis Gartside, voice over animation, explains how a detailed study of chromosome pairing can solve the problem of lost and unstable hybrids. Law carries on the discussion on the genetic control of chromosome pairing. Still shots of chromosomes(with pairing and with no pairing). Denis Gartside, voice over animation, continues. Colin Law briefly looks at two rust resistant stable hybrids and sums up the programme.
Master spool number: 6HT/71898
Production number: 00525_1178
Videofinder number: 999
Available to public: no