2种三叶草杂种F_1代后代鉴定及核型分析

Identification and Karyotype Analysis of Offspring of F_1 Hybrids to Two Kinds of Clover

蒙农三叶草1号与白三叶远缘杂种F1代为高度不育植株，在田间栽植的前2年仅开花，不结实，但是从第3年之后出现结实现象。为了探索F1代的结实机理，试验采用根尖染色体压片技术，对杂种F1代所结种子进行了体细胞染色体鉴定，并对根尖染色体压片条件进行了探索和优化。结果表明，F1代所结种子的体细胞染色体数目在40～48范围内变动,个别细胞中有染色体加倍现象和混倍体现象。杂种F1代体细胞染色体数为40，蒙农三叶草1号为48。6～3植株的种子体细胞染色体数为44，初步确定为杂种F1代与蒙农三叶草1号自然回交所得，其核型公式为：2n=30m＋14sm，属于2A型。

Hybrids F1 from distant hybridization of Trifolium ambiguum Bieb ev. Mengnong No. 1 and T. repens were highly sterile plants,which were just flowering instead of seeding over the past two years of the field planting. However, it started to fructification from the third year. In order to explore the seeding mechanism of F1 ,the technology of root tip chromosome tableting was used to identify the somatic chromosome of F1＇s seeds, meanwhile the condition of the tableting technology was explored and optimized. The results turned out that the somatic chromosome number in the seeds of F1 ranged from 40 to 48, and some cells of individuals emerged into chromosome doubling phenomenon and mixoploid. The chromosome number of somatic cells in F1 hybrids was 40,and 48 in T. ambiguum Bieb cv. Mengnong No.1. The somatic chromosome number of the 6-3% seeds was 44, which was initially identified as the resulting of backcross of F1 hybrids with T. ambiguum Bieb ev. Mengnong No.1 ,and its karyotype formula was 2n=30m＋ 14sin, which belonged to the type of 2A.