Creating novel germplasms of chrysanthemum by employing the Ajania pacifica

Chinese. 将矶菊的优异性状或基因导入栽培菊花，进行菊花种质创新，创造既可观花又可观叶的菊花新种质。利用远缘杂交获得栽培菊花品种‘意大利红’（2n=6x=54）与矶菊正反交杂种F1，并进一步以正反交杂种F1为母本，‘意大利红’为父本进行回交，获得回交后代；利用扦插苗根尖进行杂种F1和回交后代中期染色体计数。正反交杂种F1染色体数目均介于64～72，以70～72为主；正反交杂种F1回交后代染色体数目介于52～63，以60～63为主。正反交杂种F1回交后代的株高、冠幅、叶形、叶片柔毛、分枝性等性状的遗传表现基本一致，介于原始双亲之间，较杂种F1更接近回交亲本‘意大利红’，说明这些性状为数量性状。舌状花的遗传表现正反交杂种F1回交后代间存在差异，正交（‘意大利红’×矶菊）F1的回交后代舌状花先端不分裂，且不同个体间颜色变化丰富；反交（矶菊ב意大利红’）F1的回交后代舌状花先端1～4裂，以2、3裂为主，颜色较单一，表明可能与细胞质遗传有关。研究证明远缘杂种生殖过程正常，两属间有很近的亲缘关系。实现了矶菊与栽培菊花属间远缘杂交，并利用栽培菊花品种进行回交获得了一批既可观花又可观叶的新种质。

English. Unique ornamental characteristics of A. pacifica were introduced into the commercial chrysanthemum (Dendranthema×grandiflonum) cultivars in order to create novel germplasm of chrysanthemum that has ornamental values in both leaves and flowers. Reciprocal cross between cultivar ‘Yidalihong’ (2n=6x=54) and A. pacifica (2n=10x=90) were made via conventional hybridization. The obtained F1 progenies were subsequently backcrossed with one of the parents of ‘Yidalihong’. The mitosis metaphase chromosome number was investigated in root tips of cut seedling. The morphological parameters were measured. The chromosome number in F1 progenies of reciprocal cross varied from 64 to 72, and mostly from 70 to 72. The chromosome number in progenies of backcross between F1 progeny and ‘Yidalihong’ varied from 52 to 63, mostly from 60 to 63. Morphological characteristics such as plant height, canopy, phylliform, epidermal hair of leaf, branching and ramification in progenies of backcross uniformly exhibited intermediate characteristics between parents, but more resembled those of ‘Yidalihong’ than those of F1 progeny to some extents. It implied that these characteristics were quantitative traits. However, individuals of progenies of backcross differed in the morphology of ray florets. The anterior extremity of ray florets in progenies of backcross between F1 progeny (‘Yidalihong’ and A. pacifica) and ‘Yidalihong’ was not cloven and rich in flower color. However, progenies of backcross between F1 progeny (A. pacifica and ‘Yidalihong’) and ‘Yidalihong’ showed 1 to 4 lobe-ray-florets (mainly 2 or 3 lobes) and poor flower color. It suggested that phenotype of ray florets in progenies of backcross was likely regulated by cytoplasmic genes. Intergeneric hybridization was successfully attempted between A. pacifica and commercial cultivars. When the F1. progeny of intergeneric hybridization was subsequently backcrossed with commercial cultivar, novel germplasms that have ornamental values of both in leaves and flowers were created. Normal morphological appearance and somatic chromosome behavior of the majority of progenies resulted expected somatic chromosome count, which implied the high degree of homology between genomes of two closely related parents.