Creation And Genetic Analysis Of The Different Ploidy Maize-Z. Perennis Hybrids

In this study, different ploidy materials were created by maize (2n=20,40) and Zea perennis. MP30 was successfully obtained by pollinating maize with Zea perennis pollens; MP40 was the hybrid of autotetraploid maize xZea perennis and MP60 was obtained by chromosome-doubling for MP30. The chromosome number and composition, meiotic behaviors of PMCs, plant morphology, characters of pollen and stomata were observed. The aim was to analysis the genetic behavior of different materials, compare the genomes relationship between maize and Zea perennis, analysis phenotypic traits of plants and polyploidy heterosis, according to planting material and the theoretical basis for genetic and breeding. The main results were as follows:1. Hybridization was conducted among maize, Zea perennis and hexaploid MP60 (obtained by chromosome-doubling plant of maize×Zea perennis). The seed rate of diploid and tetraploid maize with Zea perennis were 9.74% and 24.68%, respectively; the seed rate of MP60 with tetraploid maize and Zea perennis were 33.33% and 27.50%, respectively. MP30 was successfully obtained by pollinating maize with Zea perennis pollens; MP40 was the hybrid of autotetraploid maize×Zea perennis. MPM50 was the hybrid of hexaploid MP60 x autotetraploid maize. MPP50 was the hybrid of MP60xZea perennis.2. The chromosome number of different ploidy materials was studied. It showed that the chromosome number of ZM20, ZM40, ZP40, ZM30, MP30, MP40, MP60 were 20,40,40,30,30,40,60; The genome homology of MP30, MP40 and MP60 were analyzed by genomic in situ hybridization, the results show that MP30 contained 10 maize chromosomes and 20 Zea perennis chromosomes, MP40 contained 20 maize chromosomes and 20 Zea perennis chromosomes, MP60 contained 20 maize chromosomes and 40 Zea perennis chromosomes. Stability of chromosome number was observed in different ploidy materials, ZM20 and ZP40 were most stable, ZM40, MP40 and MP60 were not stable, MP60 was lowest.3. The chromosome behavior of the pollen mother cells in meiosis was studied. The configuration of at PMCs at diakinesis was counted. The average configuration of ZM20 was 2n=10Ⅱ; The average configuration of ZP40 was 2n=40=4.66Ⅳ+0.29Ⅲ+9.98Ⅱ+0.54Ⅰ; The average configuration of ZM40 was 2n=40=8.02Ⅳ+0.14Ⅲ+3.61Ⅱ+0.26Ⅰ; The average configuration of ZM30 was 2n=30= 7.80Ⅲ+2.58Ⅱ+1.44Ⅰ; The average configuration of MP30 was 2n=30=4.74Ⅲ+5.4Ⅱ+4.9ⅠⅠ; The average configuration of MP40 was 2n=40=3.88Ⅳ+0.23Ⅲ+11.57Ⅱ+0.67Ⅰ; The average configuration of MP60 was 2n=60= 0.14Ⅵ+5.15Ⅳ+4.52Ⅲ+10.7311+3.48Ⅰ. Comparing the genomes relationship between maize and Zea perennis, maize genome was A and B, Zea perennis genome was A and C.4. The pollen fertility and self-seed rate of different materials was counted, the results showed that the pollen fertility of ZM20, ZM30, ZM40, ZP40, MP40, MP30, MP60, MPM50, MPP50 was 98.88%, 41.7%,88.64%,92.25%,91.53%,19.95%,75.61%,81.68%,41.63%; self-seeds rate of each material were 99.31%,0.32%,74.34%,92.24%,0%,81.70%,58.13%,38.62%,8.90%, respectively. 5. The morphological characters among different materials were analyzed. The results showed that morphological characters of allopolyploid was related to ratio of the chromosomes of maize and Zea perennis; Plant height, stem points branch numbers, tiller numbers, leaf area, and other some traits, MP30 showed heterosis; MP40 did not show heterosis; Polyploidy effects were studied in stem circumference, leaf number, leaf length, leaf width and leaf area, and other traits; MP60 showed polyploidy effects at plant height and stem circumference, other traits did not have the advantages of polyploidy.6. The characters of pollen and stomata were observed. It showed that pollen grain and stomata among those materials were significant difference. The pollen and stomata of maize were larger than Zea perennis; at same ploidy levels, the more ploidy was higher, the pollen grains, length and area of stomata were larger. At same ploidy levels, the more maize genomes, the more pollen and stomata were larger; the more ploidy levels was higher, stomata density was smaller, different specie materials was not significant.