Haploids as a tool in breeding polyploids
| dc.contributor.author | Th. Hermsen, J.G. | |
| dc.date.accessioned | 2014-07-10T06:00:09Z | |
| dc.date.available | 2014-07-10T06:00:09Z | |
| dc.date.issued | 1984-05 | |
| dc.description.abstract | The terminology used is briefly explained origin and induction of haploids in vivo are treated along with in vitro induction. Monoploids as such are rarely utilized in breeding but are valuable for basic research on phylogeny, genetics, and mutagenesis. Doubled (mbno)haploids, coded DH, obtained through cokhicine-doubling of haploids from diploids and allopolyploids have been studied in many crops. In autogamous crops, DH-lines can be released as cultivars or used as parents for further crosses, e.g., in a recurrent selection program to improve populations. They enable evaluation of populations from crosses already from Fj onwards. Time saving and increased efficiency of selection are major advantages because of homozygotization in one generation and a reliable discrimination between genotypes. Non-additive variance is completely eliminated and environmental variance can be minimized in the testing procedure. In allogamous crops DH-lines may be used as parents of hybrid varieties and of synthetic varieties. Owing to inbreeding depression, the number of useful DH-lines may be reduced. Specific potentials of DH-lines are discussed: all-male asparagus hybrids and homo-zygous potato lines that bypass all natural barriers to repeated selfing. DH-lines proved to be useful for analysis of the genetics of qualitative and quantitative characters. Dihaploids from autotetraploid crops allow breeding at the diploid level and greatly facilitate the use of diploid wild and cultivated species. Dihaploids mostly have a reduced fertility or are sterile particularly on the male side; flowering may be poor, and aberrant plants are frequently found. Dihaploids can be efficiently produced in potato and alfalfa. Apart from the advantages of breeding at the diploid level, dihaploids are effective tools in capturing the genetic diversity of related diploid species. Both in potato and alfalfa first-division-restitution-(FDR)2n-gametes are effective instruments for intact transfer of hetero-zygosity to the autotetraploid level, thus increasing the level of multi-allelism and the performance of the tetraploid progeny. The potential of the dihaploid and 2n-gametes approach is most obvious in vegetatively propagated autotetraploids. Index Descriptors: haploids, breeding, early generation testing, recurrent selection, homozygous lines, anther culture, and pseudogamy. | en_US |
| dc.identifier.citation | IOWA State Journal of Research, May, 1984, Vol. 58, No. 4 | en_US |
| dc.identifier.uri | http://hdl.handle.net/123456789/3960 | |
| dc.language.iso | en | en_US |
| dc.subject | haploids | en_US |
| dc.subject | Breeding | en_US |
| dc.subject | early generation testing | en_US |
| dc.subject | recurrent selection | en_US |
| dc.subject | homozygous lines | en_US |
| dc.subject | Anther culture | en_US |
| dc.subject | pseudogamy | en_US |
| dc.title | Haploids as a tool in breeding polyploids | en_US |
| dc.type | Article | en_US |