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当八倍体小黑麦与七倍体杂种回交时,七倍体×八倍体(以下简称“七×八”)组合的子房受精正常,80％的受精子房不能形成有胚乳的种子,有胚乳种子中能成株的仅有20％,回交效率为1％～2％,远低于八倍体×七倍体(以下简称“八×七”)组合的29.07％。通过分析“八×七”回交种子和七倍体F_1杂种根尖染色体数分布发现,八倍体小黑麦雌配子R染色体平均丢失率为0.133,具28染色体数的整倍体配子对27染色体数的非整倍体配子不具有竞争优势;父本七倍体杂种雄配子R染色体的平均丢失率为0.713,整倍体雄配子的竞争能力是非整倍体(染色体数27)雄配子的48.2倍。“七×八”组合回交效率低的原因可能是雌配子间竞争能力低,各种R染色体数的雌配子都能参与双受精,由于不完整的R组染色体对胚乳发育的干扰,大部分合子不能形成能成株的种子。
When the octoploid triticale is backcrossed with the heptaploid hybrid, the ovary with a combination of hensex × octagen (hereinafter referred to as “seven × eight”) is normal, and 80% of the sperm cells can not form an endosperm Seeds, with only 20% of the endosperm seeds can be adult, the backcross efficiency of 1% to 2%, far below octoploid × seven times (hereinafter referred to as “eight × seven”) combination of 29.07%. By analyzing the chromosome number distributions of the backcrossed seeds and the seven-hybrid F_1 hybrids, we found that the average loss rate of R chromosome of the octoploid triticale was 0.133, and the number of euploid gametes with 28 chromosomes was 27 Chromosome number of aneuploid gametes did not have competitive advantage; the average loss rate of R chromosome of the male segregant male gametes was 0.713, and the competition ability of eumlogenetic male gametes was male gametes of aneuploid (chromosome 27) 48.2 times. The reason for the low efficiency of backcrossing of “seven × eight” combinations may be that the competition ability between female gametes is low. Female gametes with various R chromosome numbers can participate in double fertilization. Due to the interference of incomplete R chromosomes on the development of endosperm, most Zygotes can not form seeds that can become adults.