F1 Hybrids
(d) Cross breeding and F1 hybrids. In animals, individuals from different breeds may produce a new crossbreed population with improved characteristics. As an F2 population will have a wide variety of genotypes a process of selection and backcrossing is required to maintain the new breed. Alternatively the two parent breeds can be maintained to produce crossbred animals for production.
(e) In plants F1 hybrids, produced by the crossing of two different inbred lines, creates a relatively uniform heterozygous crop. F1 hybrids often have increased vigour and yield. The F2 generation is genetically variable and of little use for further production although it can provide a source of new varieties. Test crosses can be used to identify unwanted individuals with heterozygous recessive alleles. (f) Genetic technology. As a result of genome sequencing, organisms with desirable genes can be identified and then used in breeding programmes. Using genetic transformation techniques a single gene can be inserted into a genome which can then be used in breeding programmes.
