Coastal Plain Experiment Station, University of Georgia, 31793, Tifton, GA, USA.
Theor Appl Genet. 1984 Nov;69(1):97-100. doi: 10.1007/BF00262551.
Pearl millet, Pennisetum americanum L. Leeke-napiergrass, Pennisetum purpureum Schum. amphiploids (2n=42) were crossed with pearl millet X Pennisetum squamulatum Fresen. interspecific hybrids (2n=41) to study the potential of germplasm transfer from wild Pennisetum species to pearl millet. These two interspecific hybrids were highly cross-compatible and more than two thousand trispecific progenies were produced from 17 double crosses. All doublecross hybrids were perennial and showed a wide range of morphological variations intermediate to both parents in vegetative and inflorescence characteristics. Some crosses resulted in sublethal progenies. Chromosomes paired mainly as bivalents (¯x15.88) or remained as univalents. At metaphase I, trivalents, quadrivalents, an occasional hexavalent and a high frequency of bivalents indicated some homeology among the genomes of the three species. Delayed separation of bivalents, unequal segregation of multivalents, lagging chromosomes, and chromatin bridges were observed at anaphase I. Although approximately 93% of the double-cross hybrids were male-sterile, pollen stainability in male-fertile plants ranged up to 94%. Seed set ranged from 0 to 37 seed per inflorescence in 71 plants under open-pollinated conditions. Apomictic embryo sac development was observed in double-cross progenies when crosses involved a pearl millet x P. squamulatum apomictic hybrid as pollen parent. These new double-cross hybrids may serve as 'bridging hybrids' to transfer genes controlling apomixis and other plant characteristics from the wild Pennisetum species to pearl millet.
珍珠粟，Pennisetum americanum L. 象草，Pennisetum purpureum Schum. 双二倍体（2n=42）与珍珠粟 X Pennisetum squamulatum Fresen. 种间杂种（2n=41）杂交，以研究从野生 Pennisetum 物种向珍珠粟转移种质的潜力。这两个种间杂种高度可杂交，从 17 个双杂交中产生了两千多个三杂种后代。所有双杂交杂种都是多年生的，在营养体和花序特征方面表现出介于双亲之间的广泛形态变异。一些杂交产生了亚致死后代。染色体主要配对为二价体（¯x15.88）或保持为单价体。在中期 I 时，三价体、四价体、偶尔的六价体和高频率的二价体表明三个物种的基因组之间存在一些同源性。在后期 I 时观察到二价体的延迟分离、多价体的不均匀分离、滞后染色体和染色质桥。尽管大约 93%的双杂交杂种是雄性不育的，但在雄性可育植物中花粉可染性高达 94%。在 71 株开放授粉条件下，每穗种子数从 0 到 37 不等。当杂交涉及珍珠粟 x P. squamulatum 无融合生殖杂种作为花粉父本时，在双杂交后代中观察到无融合生殖胚囊发育。这些新的双杂交杂种可能作为“桥接杂种”，将控制无融合生殖和其他植物特征的基因从野生 Pennisetum 物种转移到珍珠粟中。
