二倍体杂交稻及其同源四倍突变体生物学特性比较分析

Biological Characteristics of Dilpoid Hybrid Rice and Its Autotetraploid Mutant

染色体倍性增加可拓宽基因组遗传变异的范围和增加优良基因重组的机遇,是丰富种质资源遗传多样性的有效途径之一。作者前期通过农杆菌介导遗传转化杂交稻组合滇昆优8号(DY2),发现了不含外源转基因成分的同源四倍体突变株DY4。对DY2和DY4的形态特征、雌雄育性发育、花粉母细胞减数分裂过程中的染色体行为、自交后代的遗传行为等生物学特性进行了比较分析。结果表明,相对于DY2,DY4的种子体积明显增大,但分蘖数和结实率明显降低,生育期延长;DY4在第2次减数分裂时期小孢子发育出现异常,导致花粉部分败育,但其可育度仍保持在70%左右;DY4的胚囊发育多为异常,这可能是导致DY4结实率低的主要原因;DY4有4套染色体组,其遗传和分离更复杂,其不同座位的杂合状态可维持更多世代。本研究为杂交稻多倍体育种以及四倍体水稻的杂种优势利用提供一定的理论参考。

Increasing chromosome ploidy can broaden the range of genetic variation and increase the chance of good gene recombination,which is one of the effective ways to enrich the genetic diversity of germplasm resources.We identified DY4,an autotetraploid mutant without exogenous transgenic components,through agrobacterium-mediated genetic transformation of hybrid rice combination Diankunyou 8(DY2).The biological characteristics of DY2 and DY4,such as morphological characteristics,pollen fertility and embryo sac development,chromosome behavior in pollen mother cells during meiosis,and genetic behavior of selfing progeny were compared and analyzed.The results showed that compared with DY2,DY4 increased obviously in seed size and extended the growth period,but decreased obviously in the number of tillers and seed setting rate.DY4 showed abnormal microspore development during the second meiosis,resulting in partial abortive pollen,but its pollen fertility remained at about 70%.The embryo sac development of DY4 was mostly abnormal,which may be the main reason for the low seed setting rate of DY4.DY4 has four sets of chromosomes,so its inheritance and separation are more complex,and its heterozygous state of different loci can be maintained for more generations.This study provides some theoretical reference for polyploid breeding of hybrid rice and heterosis utilization of tetraploid rice.