- The goal of plant improvement is to create superior plants from existing ones (higher yield, improved quality, resistance to abiotic and biotic stress).
- Ability of a particular trait to be manipulated is determined by environment and the genotype. Heritability is the one of the most important concept in the plant breeding heritability is the ratio of the genetic variance to phenotypic variance if particular plant has a higher heritability these plants can be used for breeding programs.
Methods to improve plants
- Determine the breeding objectives – high yield, disease resistance
- Assemble heritable variation – all variations are not heritable mainly disturb by different environmental conditions. It is impossible to conduct the breeding programs without heritable variations.
- Recombine the variation by crossing or hybridization – new genetic variations have been developed.
- Select desirable recombinants and evaluate
Breeding systems of plants
- Self pollination – pollen grains are transferred from the anther of one flower to the stigma of the same flower or that of another flower from the same plant, maintain the genetic uniformity
- Cross pollination – pollen transfer from the anthers of one flower of a plant to the stigma of a flower of a different plant
Breeding methods for self–pollinated species
- Mass selection
- Pedigree selection – an extension of the pure–line breeding, started by crossing parents of a known genotype with desirable traits, such as high yield, disease resistance, these parents are then crossed to produce a new generation of plants. Best offsprings are then selected and the process is repeated until the expected desirable level is achieve, time-consuming and labor-intensive, but these process produce high genetic have high genetic purity
- Backcross breeding – Used for improving an existing highly desirable cultivar that is deficient
in one or few characteristics (hybrid plant with a desirable trait is crossed with one of its parent plants that does not have the desired trait.)
