通过对植物染色体数目的研究,发现在同一属的植物里,不同的种在染色体数目上存在着倍数的关系。例如小麦属里,一粒小麦具有14个染色体,硬粒小麦具有28个染色体,普通小麦具有42个染色体。这三个数目都是“7”的倍数。一粒小麦性细胞的染色体数目是“7”通称单倍体,体细胞的染色体数目是“7”的二倍,称二倍体小麦;硬粒小麦体细胞的染色体数目是“7”的4倍,称四倍体小麦;普通小麦体细胞的染色体数目是“7”的6倍,称六倍体小麦。凡是染色体数目的倍数大于基数(单倍体)3倍以上都统称为多倍体。本世纪来,由于多倍体的形成规律为人类所认识和逐步掌握,采取人工合成多倍体植物的方法,已较广泛地应用于一些作物的育种工作中,以期创造出更适合生产需要的品种。用多倍体方法来改造作物品种,就是作物的多倍体育种。一、细胞与染色体的结构要了解多倍休的形成,首先对于植物细胞及其染 Through the study of the number of plant chromosomes, found in the same genus plants, different species in the chromosome number there is a multiple relationship. In wheat, for example, one wheat has 14 chromosomes, durum wheat has 28 chromosomes, and common wheat has 42 chromosomes. All three are multiples of “7”. A wheat cell chromosome number is “7” is commonly known as haploid, somatic chromosome number is “7” twice, called diploid wheat; durum wheat somatic chromosome number is “4” 4 Times, called tetraploid wheat; common wheat somatic chromosome number is “7” 6 times, called hexaploid wheat. Any chromosome number multiples of more than three times the base (haploid) are collectively referred to as polyploid. This century, due to the formation of polyploid for human understanding and gradually grasp the method of synthetic polyploid plants, has been more widely used in some breeding crops to create a more suitable for production needs Variety. Multiploid methods to transform crop varieties, is crop polyploid breeding. First, the cell and chromosome structure To understand the formation of multiple Hugh, first of all for plant cells and their staining