Maize-Z.Perennis Allotetraploid As A Bridge To Transfer Exogenous Genetic Material To Maize

In this study,the maize-Zea perennis allotetraploid BC₁F₄（BC₁F₄-10 and BC₁F₄-15）,which was created by the research group,was used as a bridge to obtain a heterologous threefold by crossing with different ploidy maize（Mo17 and V182）.Body corn self-crossing offspring,backcross progeny and allotetraploid maize.It is studied by means of morphology,cytology and molecular biology.The main findings are as follows.1.There are 41 chromosomes in BC₁F₄-10,9 chromosomes in Zea perennis,26 chromosomes in corn chromosomes,and 6 chromosomes in Zea perennis and corn translocation.The number of chromosomes of BC₁F₄-15 is 40,among which there are 12 chromosomes of Zea perennis and 23chromosomes of corn,and there are 5 chromosomes of Zea perennis and corn translocation.2.Hybridization of diploid maize Mo17（2n=20）and BC₁F₄-15 resulted in allotriploid hybrid F₁.The results showed that 90%of the chromosomes in the heterologous triploid maize F₁were 30,among which there were 1-6 chromosomes of the Zea perennis,and 16-22 chromosomes of the corn,There are7-10 chromosomes of Zea perennis and corn translocation.The meiosis of F₁ pollen mother cells was abnormal.Three plants were randomly selected from F₁ and the chromosome configuration was statistically found.The average configuration of F₁ chromosome was 4.64III+5.10II+5.06I,and the variation of pollen fertility was 64.5%-86.32%,the seed rate has changed from 1.03%-7.14%.3.Reciprocal cross-crossing of allotriploid maize F₁ and Mo17 to obtain BC₁（orthogonal）and BC₁^R（reverse cross）.The results showed that the chromosome number of BC₁ plants was 19-30,among which there were 0-1 chromosomes of Zea perennis and 16-21 of corn chromosomes.and there are 2-7chromosomes of Zea perennis and corn translocation.the pollen fertility variation of BC₁ is 62.5%-83.4%,and the seed setting rate is 6.82%-95.65%.The chromosome number of 80%of plants in BC₁^R is the number of chromosomes in the parental cells（2n=20 and 2n=30）,and the chromosome number of20%plants is scattered between 20-30,among which 0-3 chromosomes in Zea perennis,20-25chromosomes in maize,0-4 chromosomes in the Zea perennis and corn translocation.and the BC₁^Rpollen fertility range is 65.3%-80.5%.The seed setting rate is 21.43%-45.39%.4.Allotriploid maize F₂ was obtained by self-crossing the Allotriploid maize F₁.The results showed that the number of chromosomes of allotriploid F₂ was 33-36,among which the Zea perennis had 0-2 chromosomes.There are 19-27 chromosomes in maize,and there are 7-13 chromosomes in the Zea perennis and corn translocation.The F₂ pollen fertility ranged from 55.4%-79.7%,and the seed setting rate range from 0-30%.5.Hybridization of BC₁F₄-10 and V182（2n=40）to obtain allotetraploid maize F₁.The results showed that among the allotetraploid maize F₁,83.33%of the plants had 40 chromosomes,among which 2-11 chromosomes of Zea perennis,21-30 of corn chromosomes,and 5-13 chromosomes of Zea perennis and corn translocation.The F₁ pollen fertility ranged from 66.1%-85.3%,and the seed setting rate ranged from 62.57%-92.71%.6.Allotetraploid maize F₁ is selfed,and allotetraploid maize F₂ is obtained.Allotetraploid maize F₂ is continuously selfed to obtain allotetraploid maize F₃.The results showed that after 2 generations of allotetraploid maize F₁,the number of F₃ chromosomes was 40（occasional aneuploidy appeared）,among which the Zea perennis had 0-4 chromosomes,and the corn chromosomes had 29-37,there are3-9 chromosomes in the Zea perennis and corn translocation.The allotetraploid maize F₃ pollen fertility range from 44.2%-94.2%,and the seed setting rate range from 6.25%-83.18%.