Development of perennial alternatives to annual crops can alleviate some of agriculture's challenges. Perennial sorghum has the potential of being a low maintenance, drought tolerant, high yielding forage or bioenergy crop. Sorghum bicolor (L.) Moench (ATx623, CMS line) was crossed with S. propinquum (Kunth) Hitchc., and several diploid F₁ hybrids were recovered. One hybrid was treated with colchicine to produce novel tetraploids. A single tetraploid plant was recovered and is the first reported induced tetraploid S. bicolor x S. propinquum hybrid. The fertility and chromosome pairing of this tetraploid hybrid, diploid F₂ hybrids, and both parents were investigated. Pollen stainability for S. bicolor (BTx623, restorer line), S. propinquum, and the F₂ hybrids ranged from 85 to 90%, but stainability was lower (57%) for the induced tetraploid hybrid. Mean seed set of both parents was 65–67% but was 43% for the induced tetraploid hybrid. Meiotic chromosome pairing at metaphase I in both diploid (2n = 2x = 20) parents and the diploid hybrids was primarily 10 bivalents, but the hybrids had a higher frequency of univalents than either parent indicating small chromosomal differences exist between the two species. Mean meiotic chromosome pairing in the induced tetraploid hybrid (2n = 4x = 40) was 0.45 univalents 17.77 bivalents, 0.02 trivalents, and 0.98 quadrivalents per cell. These findings corroborate previous reports that S. bicolor and S. propinquum have a homologous genome.

中文翻译：

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诱导四倍体 Sorghum bicolor x S. propinquum 杂种的细胞遗传学和育性

开发一年生作物的多年生替代品可以缓解一些农业挑战。多年生高粱具有成为低维护、耐旱、高产牧草或生物能源作物的潜力。Sorghum bicolor (L.) Moench (ATx623, CMS line) 与S. propinquum (Kunth) Hitchc.杂交，并回收了几个二倍体 F ₁杂种。一种杂种用秋水仙碱处理以产生新的四倍体。回收了单个四倍体植物并且是首次报道的诱导四倍体S. bicolor x S. propinquum杂种。这个四倍体杂种二倍体 F ₂的生育力和染色体配对杂种，并对父母双方进行了调查。S. bicolor（BTx623，恢复系）、S. propinquum和 F _{2 的}花粉染色性杂种的范围为 85% 到 90%，但诱导的四倍体杂种的染色性较低（57%）。父母双方的平均种子集为 65-67%，但诱导的四倍体杂种为 43%。二倍体 (2n = 2x = 20) 亲本和二倍体杂种在中期 I 的减数分裂染色体配对主要是 10 个二价，但杂种的单价频率高于任一亲本，表明两个物种之间存在小的染色体差异。诱导四倍体杂交体 (2n = 4x = 40) 中的平均减数分裂染色体配对为每个细胞 0.45 个单价、17.77 个二价、0.02 个三价和 0.98 个四价。这些发现证实了之前的报道，即双色 S. bicolor和S. propinquum具有同源基因组。