无髯鸢尾种间杂交障碍分析

目的为探究无髯鸢尾种间杂交障碍原因及子房败育时间,以西伯利亚鸢尾5个品种为亲本,与黄菖蒲、喜盐鸢尾分别进行常规杂交。方法授粉后观测种间杂交后子房发育动态,并绘制发育动态折线图;在荧光显微镜下,观测不同授粉时间后的花粉管原位萌发动态,并统计每个杂交组合的杂交结实率和种子萌发率。结果无髯鸢尾种间杂交子房在授粉后9~16 d发生败育;授粉后杂交障碍原因主要是花粉附着困难、花粉萌发率低、花粉管伸长障碍和胚囊败育的受精后障碍;黄菖蒲与西伯利亚鸢尾杂交后受精前和受精后障碍并存,喜盐鸢尾与西伯利亚鸢尾杂交主要存在受精后障碍;喜盐鸢尾与西伯利亚鸢尾的亲和性高于其与黄菖蒲杂交的亲和性。结论花粉原位萌发可作为远缘杂交前障碍检测指标,观测花粉原位萌发可及时采用相应措施,增大杂种获得率;不同品种种间亲和性不同,二倍体和四倍体在染色体条数不同的种间远缘杂交中亲和性无显著区别;不同种间杂交,正反交杂交障碍类型不同,可以通过不同种系品种间正反交,增加无髯鸢尾种间杂交亲和性,获得变异丰富的种间杂交类型。 

Analysis on the barriers of interspecific hybridization in beardless irises

ObjectiveIn order to study the crossbreeding barriers and time of ovary abortion in beardless irises, five Iris sibirica varieties were crossed respectively with Iris pseudacorus and Iris halophila var. sogdiana.MethodGrowing of pollen and ovaries after common pollination were observed and showed by figures. Rate of seed setting and germination were counted finally.ResultOvary abortion was found in 9-16 days after pollination. There were four reasons, pollen difficult adherence, low rate of pollen germination, pollen tube elongation disorders and embryo abortion for post-zygotic barrier. Post-zygotic and pro-zygotic barrier were the main reasons for the cross incompatibility between I.pseudacorus and five I. sibirica varieties. Post-zygotic was the main reason for cross incompatibility between I. halophila var. sogdiana and five I. sibirica varieties; I. halophila var. sogdiana was higher than I. pseudacorus in cross compatibitily.ConclusionThe results suggested that pollen germination can be the barrier test index before distant hybridization; appropriate measures could be done after observing pollen germination to increase seed setting rate; cross compatibility was different in varied species and there was no significant difference between diploid and tetraploid in the inter-species distant hybridization with different number of chromosomes; there were different types of crossbreeding barriers in reciprocal cross. The rate of cross compatibility can be improved in irises inter-species by reciprocal cross to get more rich offsprings.