Haploids — an Integral Part of Applied and Basic Research

Abstract

On the example of barley it will be demonstrated that the use of haploids is a common step in modern applied breeding programs. It is irrelevant whether these haploids are produced partheno- or androgenetically but normally parthenogenesis is more laborious than androgenesis since it demands both, intensive greenhouse work and in vitro equipment. In most cases microspore androgenesis has been improved to such an extent that the number of green haploid plants and derived DH lines necessary for applied work (normally about 100 DH-lines per donor genotyp) can be produced. This is particularly true for self-fertile cereals and for Brassicaceae. In crops where there are still difficulties, like most outbreeders, a concentrated input might solve the problem. In those crops where the technique works, the question is no longer how to produce haploids but rather how to use them most efficiently. When the aim is rapid incorporation of a monogenic trait the time gain is beneficial, but much more important are strategies which allow the combination of quantitatively inherited characters. Here haploids have a big potential. Further, with increasing progress in somatic hybridization, e.g. in potato, the production of haploids becomes more essential resulting in a broad haploid population as fusion parents. A rather new field of haploid usage is the molecular genome identification. Here, haploids due to their simpler segregation patterns are an important prerequisite to identify genes. Most RFLP maps of barley are based on such DH-populations. Particularly for QTL analysis unselected DH-populations are an important tool to produce reproducible DNA-polymorphisms.