利用DH技术对先玉335进行连续轮回选择，发现单倍体雄穗自然加倍能力具有极显著的累加遗传效应，这种遗传效应可以获得成倍提高。证明玉米自身遗传系统具有单倍体雄穗自然加倍遗传恢复（修复）能力。用两轮选择所获的DH²系再次杂交组群，再经杂交诱导获得单倍体植株平均雄花散粉率高达85.15%，自交结实率高达66.18%，是基础群体先玉335直接诱导单倍体株的6.99倍和9.86倍。获得的DH³系因经两轮全基因组配子体选择，最大限度地淘汰了有害、劣性基因，聚合了较多优良基因，农艺性状好，植株长势强，可直接应用于资源扩增和品种选育。单倍体雄穗自然加倍性的轮选遗传修复能力的发现与高自然加倍率材料的创制具有极其重要的应用价值，可与玉米双轮回选择育种模式相结合，构建基于自然加倍为主体的单倍体双轮回育种技术体系。

Use DH lines from Xianyu335 as source materials for haploid induction in the recurrent selection scheme, the spontaneous doubling rate of the haploid tassels had significantly increased in the next cycle and showed a cumulative genetic effect, and through using DH recurrent selection technique, the doubling rate of the haploid tassels can be doubled. It proved that performing continuous recurrent selection, the genetic makeup of the haploids had been enriched for spontaneous doubling restoration. Using hybrids between DH lines from two cycles haploid selection as source materials for haploid induction, the haploid tassel doubling rate had reached 85.15% and haploid ears showed seed set had reached 66.18%, representing a rate increase of 6.99 folds and 9.86 folds of its original source population Xianyu335. Also, because the DH lines had been selected from two cycles haploids or whole genome gamete selection, it was effectively eliminated many deleterious and bad genes, and also cumulatively combined many superior genes for agronomy and plant growth vigor. These new DHs can be directly used as parents for germplasm enhancement and new hybrid selection and breeding. The discovery of enrichment or spontaneous doubling restoration of the haploid tassels that were derived from DH recurrent selection technique and create high spontaneous doubling rate source materials showed a significant application value in maize breeding. It showed significant advantages for construct maize two cycle recurrent selection with high haploid spontaneous doubling rate to speed up breeding output.

七大农作物育种专项“主要农作物染色体细胞工程育种”、“玉米杂种优势利用技术与强优势杂交种创制”、吉林省农业科技创新工程“玉米单倍体规模化育种技术研究与示范”项目