Ricci Gléia Cristina Laverde, De Souza-Kaneshima Alice Maria, Felismino Mariana Ferrari, Mendes-Bonato Andrea Beatriz, Pagliarini Maria Suely, Do Valle Cacilda Borges
Department of Cell Biology and Genetics, State University of Maringá, 87020-900 Maringá, PR, Brazil.
J Genet. 2011 Aug;90(2):289-94. doi: 10.1007/s12041-011-0087-5.
A total of 44 accessions of Brachiaria decumbens were analysed for chromosome count and meiotic behaviour in order to identify potential progenitors for crosses. Among them, 15 accessions presented 2n = 18; 27 accessions, 2n = 36; and 2 accessions, 2n = 45 chromosomes. Among the diploid accessions, the rate of meiotic abnormalities was low, ranging from 0.82% to 7.93%. In the 27 tetraploid accessions, the rate of meiotic abnormalities ranged from 18.41% to 65.83%. The most common meiotic abnormalities were related to irregular chromosome segregation, but chromosome stickiness and abnormal cytokinesis were observed in low frequency. All abnormalities can compromise pollen viability by generating unbalanced gametes. Based on the chromosome number and meiotic stability, the present study indicates the apomictic tetraploid accessions that can act as male genitor to produce interspecific hybrids with B. ruziziensis or intraspecific hybrids with recently artificially tetraploidized accessions.
总共对44份俯仰臂形草材料进行了染色体计数和减数分裂行为分析，以确定杂交的潜在亲本。其中，15份材料的染色体数目为2n = 18；27份材料为2n = 36；2份材料为2n = 45。在二倍体材料中，减数分裂异常率较低，范围为0.82%至7.93%。在27份四倍体材料中，减数分裂异常率范围为18.41%至65.83%。最常见的减数分裂异常与染色体分离不规则有关，但染色体粘连和异常胞质分裂的出现频率较低。所有异常都会通过产生不平衡配子而影响花粉活力。基于染色体数目和减数分裂稳定性，本研究表明无融合生殖的四倍体材料可作为父本，与鲁齐臂形草产生种间杂种，或与最近人工四倍体化的材料产生种内杂种。
