Doğramaci-Altuntepe M, Jauhar P P
United States Department of Agriculture, Agricultural Research Service, Fargo, ND 58105, USA.
Genome. 2001 Feb;44(1):137-42. doi: 10.1139/gen-44-1-137.
The objective of this study was to investigate the effect of individual durum wheat (Triticum turgidum L.) chromosomes on crossability with maize (Zea mays L.) and to cytologically characterize the haploids recovered. Fourteen 'Langdon' (LDN) D-genome disomic substitution lines, a LDN Ph mutant (Ph1b ph1b), and normal 'Langdon' were pollinated with maize pollen. After pollination, hormonal treatment was given daily for up to 14 days. Haploid embryos were obtained from all lines and were aseptically cultured. From a total of 55,358 pollinated florets, 895 embryos were obtained. Only 14 of the embryos germinated and developed into healthy plants. Different substitution lines showed varying degrees of success. The most successful was the substitution 5D(5B) for both embryo formation and haploid plantlet production. These results indicate that the substitution of 5D for 5B confers on durum wheat a greater ability to produce haploids. Fluorescent genomic in situ hybridization (GISH) showed that the substitution haploids consisted of 7 A-genome chromosomes, 6 B-genome chromosomes, and 1 D-genome chromosome. Triticum urartu Turn. genomic DNA was efficient in probing the 7 A-genome chromosomes, although the D-genome chromosome also showed intermediate hybridization. This shows a close affinity between the A genome and D genome. We also elucidated the evolutionary translocation involving the chromosomes 4A and 7B that occurred at the time of evolution of durum wheat. We found that the distal segment translocated from chromosome 7B constitutes about 24% of the long arm of 4A.
本研究的目的是调查硬粒小麦（Triticum turgidum L.）单个染色体对与玉米（Zea mays L.）杂交亲和性的影响，并对获得的单倍体进行细胞学特征分析。用玉米花粉对14个“兰登”（LDN）D基因组二体代换系、一个LDN Ph突变体（Ph1b ph1b）和正常“兰登”进行授粉。授粉后，每天进行激素处理，持续14天。从所有品系中获得了单倍体胚胎，并进行无菌培养。在总共55358个授粉小花中，获得了895个胚胎。只有14个胚胎发芽并发育成健康植株。不同的代换系表现出不同程度的成功。最成功的是5D(5B)代换系，在胚胎形成和单倍体植株产生方面都表现出色。这些结果表明，用5D代换5B赋予硬粒小麦更高的单倍体产生能力。荧光基因组原位杂交（GISH）显示，代换单倍体由7条A基因组染色体、6条B基因组染色体和1条D基因组染色体组成。乌拉尔图小麦（Triticum urartu Turn.）基因组DNA能有效地探测7条A基因组染色体，尽管D基因组染色体也显示出中等程度的杂交。这表明A基因组和D基因组之间有密切的亲缘关系。我们还阐明了硬粒小麦进化过程中发生的涉及4A和7B染色体的进化易位。我们发现，从7B染色体易位而来的远端片段约占4A染色体长臂的24%。
