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Unformatted text preview: 489 15.1 Changes in chromosome number AGRICULTURAL APPLICATIONS Variations in chromosome number have been exploited to create new plant lines with desirable features. Some examples follow. Monoploids Diploidy is an inherent nuisance for plant breeders. When they want to induce and select new recessive mutations that are favor- able for agricultural purposes, the new mutations cannot be detected unless they are homozygous. Breed- ers may also want to find favorable new combinations of alleles at dif- ferent loci, but such favorable allele combinations in heterozygotes will be broken up by recombination at meiosis. Monoploids provide a way around some of these problems. Monoploids can be artificially derived from the products of meio- sis in the plant’s anthers. A cell des- tined to become a pollen grain can instead be induced by cold treat- ment to grow into an embryoid, a small dividing mass of monoploid cells. The embryoid can be grown on agar to form a monoploid plantlet, which can then be potted in soil and...
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This note was uploaded on 01/10/2011 for the course BIOL BIOL taught by Professor Johnson during the Spring '08 term at Aberystwyth University.
- Spring '08