Meiotic disturbances in F₁ hybrids and their progenies are still major problems in wide hybridization. To investigate the genome affinity reflected in chromosome pairing and segregation, we studied chromosome behaviors during meiosis in two interspecific F₁ hybrids [O. minuta × O. australiensis (Om × Oa, BCE genome) and Oa × O. ridleyi (Or, EHJ genome)] by using both traditional staining methods and genomic in situ hybridization (GISH). GISH analysis has been successfully performed on mitotic chromosomes to distinguish different Oryza genomes, but relatively fewer systematic analyses of meiotic chromosomes of interspecific hybrids have been reported. In the hybrids, highly irregular chromosome behaviors through meiosis resulted in producing microspores with unbalanced genome. At diakinesis of these two hybrids, most chromosomes present as univalent, with low frequency as bivalents and occasionally as trivalents. In a pollen mother cell, 2 to 8 bivalents and 0 to 4 trivalents were observed in the hybrid Oa × Or, and 1 to 8 bivalents and 0 to 5 trivalents were observed in the hybrid Om × Oa. GISH results indicated that 51.52% bivalents in Oa × Or and 79.65% bivalents in Om × Oa involved allosyndetic association, which indicates that recombination and introgression should be possible if viable backcrosses can be recovered even from triploid hybrids. In this study, we revealed that the meiotic disturbance due to low affinities between parental genomes is the major reason for the sterility of these two triploid interspecific hybrids. The two hybrids showing vigor in reproductive growth are potential genetic resources in future breeding programs. A better understanding of genomic affinities between these distant Oryza species can facilitate planning an effective breeding program by using wide hybridization, and efficient and routine GISH analysis is helpful to monitor alien introgression in the process.

F ₁杂种及其后代的减数分裂干扰仍然是广泛杂交中的主要问题。为了研究反映在染色体配对和分离中的基因组亲和力，我们研究了两个种间F ₁杂种[ O. minuta  ×  O. australiensis（Om  ×  Oa，BCE基因组）和Oa  ×  O. ridleyi（或，EHJ ）在减数分裂过程中的染色体行为。基因组]]，同时使用传统的染色方法和基因组原位杂交（GISH）。已成功对有丝分裂染色体进行了GISH分析，以区分不同的Oryza基因组，但有关种间杂交的减数分裂染色体的系统分析相对较少。在杂种中，通过减数分裂的高度不规则的染色体行为导致产生具有不平衡基因组的小孢子。在这两个杂种的诊断中，大多数染色体为单价，低频为二价，偶尔为三价。在花粉母细胞中，在杂种Oa  ×  Or中观察到2至8个二价和0至4个三价，在杂种Om  ×  Oa中观察到1至8个二价和0至5个三价。GISH结果表明，Oa  ×  Or中有51.52％二价，Om  ×  Oa中有79.65％二价涉及同种异体的关联，这表明如果即使从三倍体杂种中也可以回收到可行的回交，重组和渗入应该是可能的。在这项研究中，我们揭示了由于亲本基因组之间亲和力低而导致的减数分裂干扰是这两个三倍体种间杂种不育的主要原因。在繁殖生长中表现出活力的两个杂种是未来育种计划中的潜在遗传资源。更好地了解这些遥远的Oryza物种之间的基因组亲和性，可以通过广泛杂交来促进制定有效的育种计划，而高效且常规的GISH分析有助于监控过程中的外来基因渗入。