种子老化对美洲狼尾草种质资源遗传完整性的影响

Eeffect of seeds aging on genetic integrity in Pennisetum glaucum germplasm resources

为确定适合美洲狼尾草(Pennisetum glaucum)种子更新的发芽率,采用人工梯度老化的方法,对其在45℃、99%相对湿度条件下分别处理0、4、8、12、16、20、24 h,再对梯度老化后的材料进行遗传完整性分析。结果表明:与对照组相比,经人工梯度老化后的美洲狼尾草的发芽率、多态性条带百分率(percentage of polymorphic bands,PPB)、等位基因数(number of alleles,Na)、有效等位基因数(effective number of alleles,Ne)、Nei’s基因多样性指数(Nei's gene diversity index,H)和Shannon-Wiener多样性指数(Shannon's information index,I)均有不同程度降低,且与老化时间负相关;发芽率为68.23%时,除等位基因数以外,其他遗传多样性相关参数均与对照组差异显著(P<0.05),说明美洲狼尾草种子更新的发芽率为68.23%。综上,当美洲狼尾草种子的发芽率为68.23%时,应进行种质资源的更新;gSSR分子标记可以作为探究种子老化对种质资源遗传完整性的影响的检验手段,对于异质种质资源材料,低发芽率不利于种质资源遗传完整性的保持。

To elucidate the germination rate of pearl millet(Pennisetum glaucum)germplasm resources,seeds were artificially aged at 45℃and 99%relative humidity for 0,4,8,12,16,20 and 24 h.After aging,they were analyzed for genetic integrity.The results showed that the germination rate,percentage of polymorphic bands(PPB),number of alleles(Na),effective number of alleles(Ne),Nei’s gene diversity index(H),and Shannon-Wiener’s information index(I)of the treated group were lower than 0 h(CK)and had a negative correlation with aging time,which indicated that the genetic integrity of aged seeds decreased compared with CK.Aged seeds were significantly different(P<0.05)from CK regarding of PPB,Ne,H and I,when the germination rate went down to 68.23%,which indicated that the regeneration germination rate of P.glaucum was 68.23%.In conclusion,the germplasm resources of P.glaucum should be updated when the germination rate decreased to 68.23%and the genomic-SSR markers could be used to evaluate the effects of seed aging on genetic integrity for its high polymorphism,and low germination was a disadvantage for maintaining the genetic integrity of germplasm resources.