7个鹅观草居群的形态学和细胞遗传学研究

鹅观草广泛分布于我国各地及日本和朝鲜等地,具有丰富的遗传变异,种内变异类型丰富,一些居群间存在明显的生殖隔离。本研究利用人工杂交、形态学、繁育学及染色体组分析方法对来自四川雅安、四川宜宾新文、四川宜宾翠屏山、青海、新疆、浙江及山东的7个鹅观草居群进行了遗传分化研究。结果显示:(1)不同居群在株高、穗长、外稃长等表型性状存在差异,各居群间杂种F1表型性状普遍优于两亲本居群,但是颖宽个别性状劣于亲本。(2)各居群间杂种F1染色体配对水平总体较高,但也存在差异;二价体数目变异范围为19.77~20.91,单价体数目变异范围为0.18~2.46,还有低频率的三价体、四价体出现。(3)杂种F1的育性为78.9%~89.67%,自然结实率43.05%~77.98%,其中浙江与四川宜宾翠屏山居群的杂种F1的自然结实率最低(43.05%)。以上结果表明,7个鹅观草居群间存在一定程度的分化,且与各居群的地理分布呈正相关;四川宜宾与浙江居群之间存在一定的生殖隔离,遗传变异较大。

Cytogenetic and morphological studies on seven populationsof Roegneria kamoji Ohwi(Triticeae: Poaceae)

Roegneria kamoji Ohwi exited widely in China, Japan and Korea. Genetic variations and variations within species of R. kamoji were reported in previous studies. In this study, we using artificial hybridization, morphology comparison, thremmatology and genome analysis studies for exploring the differentiation of seven populations of R. kamoji from Sichuan, Qinghai, Xinjiang, Zhejiang and Shandong. The results showed that: 1) the heights, length of spike, length of lemma were different for these populations. The phenotypic traits of F₁ hybrid were better than their parents, while the floret number and width of glume were inferior to their parents. 2) Meiotic pairing in hybrids averaged 19.77 to 20.91 bivalents per cell, 0.18 to 2.46 univalents per cell, and a low frequency of trivalents and tetravalents. 3) The fertility and natural seed set of the F₁ hybrids ranged from 78.9% to 89.67%, 43.05% to 77.98%, respectively. The lowest seed set (43.05%) was found in hybrid between Zhejiang and Yibin. The above results suggested that differentiations were existed in seven populations of R. kamoji, and it positively correlated with the geographical distribution of the populations. The natural seed set of hybrid between Zhejiang and Yibin was only 43.05%, which is lower than 50%, certifying that reproductive isolation existed between these two populations of R. kamoji.