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- Title
Spontaneous haploids in durum wheat: their cytogenetic characterization.
- Authors
Jauhar, Prem
- Abstract
Durum or macaroni wheat ( Triticum turgidum L., 2 n = 4 x = 28; AABB genomes) arose as a natural hybrid between two wild species, Aegilops speltoides Tausch (2 n = 2 x = 14; BB genome) and Triticum urartu Tumanian (2 n = 2 x = 14; AA genome). The two progenitors hybridized in nature about half a million years ago and gave rise to tetraploid wheat, presumably in one step as a result of functioning of unreduced gametes in their hybrid BA (amphihaploid). It is easily possible to go back on the evolutionary scale and obtain durum haploids BA, and then regenerate tetraploid durum plants from them. Interestingly, such a reversion to haploidy does occur in nature as well, although at a very low frequency. This article reports on the occurrence of two spontaneous durum haploids and describes their chromosomal characteristics. The haploids (euhaploids, to be precise) had 14 somatic chromosomes, which, on fluorescent genomic in situ hybridization (fl-GISH), could be distinguished as 7 A-genome and 7 B-genome chromosomes. At meiosis, only 2.3 and 2.7% of the chromosomes paired in the two haploids, because of the presence of the homoeologous pairing-suppressor gene, Ph1. The Ph1-induced lack of pairing is a prerequisite for chromosome doubling through the formation of unreduced gametes that give rise to tetraploid durum wheats.
- Subjects
DURUM wheat; HAPLOIDY; PLANT chromosome numbers; FLUORESCENCE in situ hybridization; PLANT genomes
- Publication
Euphytica, 2006, Vol 148, Issue 3, p341
- ISSN
0014-2336
- Publication type
Article
- DOI
10.1007/s10681-005-9044-9