Alternative explanation: development of a mapping population
A mapping population needs to have diversity in traits (must be segregating). In autogamous crops, this is often achieved by crossing rather contrasting parents. The two parents of a mapping population:
- must be homozygous in autogamous species (analysis of F2, RIL or BC)
- are heterozygous for many loci in allogamous species
- must differ as much as possible from each other for important agronomic traits, in order to get segregation following the F1 in the offspring (autogamous crops) or must themselves be heterozygous for traits of interest (allogamous crops)
In most crops, the number of polymorphic markers is sufficient to develop linkage maps.