一个大穗型小麦-黑麦异代换系的细胞学和SSR鉴定

Identification of a Rye Alien Substitution Line with Big Ear by Cytology and SSR Analysis

为了深入研究大穗型小麦的遗传基础,利用细胞学和SSR方法对从普通小麦与六倍体小黑麦杂交后代中选育的大穗型小麦-黑麦材料7-25进行了鉴定。结果表明,品系7-25的根尖细胞染色体数目为2n=42,花粉母细胞减数分裂中期I(PMC MI)绝大多数细胞内可观察到21个二价体,平均染色体构型2n=20.94Ⅱ+0.11Ⅰ,它与中国春杂种F1的多数花粉母细胞染色体构型为2n=20Ⅱ+2Ⅰ,因此表明品系7-25是一个小麦-黑麦的二体异代换系。使用位于黑麦1R^3R、5R^7R染色体上的黑麦特异的20对SSR引物,其中有2对引物SCM268和SCM120能在7-25品系中稳定地扩增出黑麦特异染色体片段。SCM268、SCM120分别位于黑麦5R染色体的短臂和长臂上。综合细胞学和SSR分析结果,进一步确定品系7-25为小麦-黑麦5R代换系。

In order to learn its genetic component and use it better, line 7-25, an alien substitution line of rye with big ear from the progeny of a cross between common wheat and hexiploid triticale investigated cytology and simple sequence repeat（SSR）analysis . The results showed that chromosome numbers of line 7-25 in root tip cell was 2n=42 with 21 bivalents observed in most PMC at MI,and the average chromosome configuration was 2n=20. 94Ⅱ＋0. 11I , and the chromosome configuration （2n=20Ⅱ ＋2I）was observed in most PMC at MI of F1 between line 7-25 and Chinese spring. Therefore,it was an alien disomic substitution line with one pair chromosomes of rye. Twenty pairs of SSR primes located on chromosomes of 1R～3R,SR～TR of rye were used for SSR amplification,the specific DNA fragments of rye could be amplified in line 7-25 by primers of SCM268 and SCM120 which located in the short arm and long arm of 5R chromos orne of rye respectively. These results indicated that line 7-25 was a wheat-rye substitution line with one pair chromosomes of 5R. This line has multispikelets with more number of grains per ear, higher grain weight and more ears per plant, it may play important role in wheat breeding and genetics improvement.