Abstract：
CONCLUSIONS: Wheat lines harboring wild-relative chromosomes can be karyotypically unstable during long-term maintenance. Tissue culture exacerbates chromosomal instability but appears inefficient to induce somatic homoeologous exchange between alien and wheat chromosomes. We assessed if long-term refrigerator storage with regular renewal via self-fertilization, a widely used practice for crop germplasm maintenance, would ensure genetic fidelity of alien addition lines, and explored the possibility of inducing somatic homoeologues exchange by tissue culture. We cytogenetically characterized sampled stock seeds of originally confirmed 12 distinct wheat-Thinopyrum intermedium alien addition lines (dubbed TAI lines), and subjected immature embryos of the TAI lines to tissue culture. We find eight of the 12 TAI lines were karyotypically departed from their original identity as bona fide disomic alien addition lines due to extensive loss of whole-chromosomes of both Th. intermedium and wheat origins during the ca. 3-decade storage. Rampant numerical chromosome variations (NCVs) involving both alien and wheat chromosomes were detected in regenerated plants of all 12 studied TAI lines, but at variable rates among the wheat sub-genomes and chromosomes. Compared with NCVs, structural chromosome variations (SCVs) occurred at substantially lower rates, and no SCV involving the added alien chromosomes was observed. The NCVs manifested only moderate effects on phenotypes of the regenerated plants under field conditions.
摘要：
结论：携带野生相对染色体的小麦品系在长期维持过程中可能在核型上不稳定。组织培养加剧了染色体的不稳定性，但似乎无法诱导外来和小麦染色体之间的体细胞同源交换。我们评估了长期冰箱储存是否通过自体受精定期更新，一种广泛用于作物种质维护的做法，将确保外来加线的遗传保真度，并探讨了通过组织培养诱导体细胞同源物交换的可能性。我们对最初确认的12种不同的小麦-thinopyrum中间外来添加系（称为TAI系）的采样种子进行了细胞遗传学表征，并对TAI系的未成熟胚进行组织培养。我们发现，由于两个Th的全染色体大量丢失，12个TAI系中的8个在核型上偏离了它们的原始身份，成为真正的二体外来加系。中间和小麦的起源。3个十年的存储。在所有12个研究的TAI品系的再生植物中都检测到涉及外来和小麦染色体的大量数字染色体变异（NCV），但是在小麦亚基因组和染色体之间的比率不同。与NCV相比，结构染色体变异（SCV）的发生率大大降低，并且没有观察到涉及添加的外来染色体的SCV。在田间条件下，NCV对再生植物的表型仅表现出中等影响。
