摘要
四倍体变异既来自染色体数量、结构的变异以及基因突变、重组,同时也与核-质之间、合子胚与胚乳之间协调关系的变化有关.其变异率可以预料高于二倍体.纯合的四倍体是一个相对平衡的系统,继续选择是无效的.不同物种四倍体的表型变异有一定差别,经常是既有有利变异,也有不利变异.四倍体育种应取利避害,针对具体情况采用适宜的选择方法.减数分裂四倍体由2x的2n配子和经选择的4x的正常配子融合产生,避免了化学诱变的不良影响,能够较好的实现双亲优良性状的互补,也比较容易稳定.四倍体可以直接育成稳定品种,也可以进行杂种优势的利用.利用多倍体作桥梁种有利于促进种或种群间的基因交流.三倍体可能表现出强的杂种优势,也可能产生无籽果实,但并不是所有物种都能直接利用三倍体品种进行繁育.对四倍体种或二倍体种或人工四倍体种的改良选择,利用双单倍体都具重要意义.利用多倍体选育二倍体品种,进行非倍性诱变育种是多倍体育种的重要组成部分.多倍体和无融合生殖结合利用,利用多倍体创造新种质,进行遗传研究也有重要价值.
The variation of tetraploid is caused by the variation of the quantity and structure of chromosome and gene mutation,recombination as well as by the variation of coordinating relationship between karyon and cytoplasm and that between zygote embryo and endosperm.Its variation rate is expected to be higher than diploid.Homozygous tetraploid is a relatively balanced system,the continued selection is invalid.Phenotype variations of tetraploid in different species are different,both the advantage variations and disadvantage variations appear in frequency.It should keep advantage traits and avoid disadvantage traits to make a tetraploid breeding,a suitable selection method should be taken according to specific situation.Meiosis tetraploid is generated from the blending of 2n gamete of 2x and selected normal gamete of 4x,the blight of chemical mutation is avoided,the complementation of good traits from parents is realized and the stability is better.The tetraploid can be either directly bred into the stable variety or hybrid with advantage.As a bridge variety tetraploid is good for gene communication of species or group of species.Both Strong hybrid advantages and seedless fruits are possible in triploid,but triploid breeding can not be applied in all species.It is of significant importance to use dihaploid to better selecting tetroploid species,diploid species,artificial tetraploid species.It is an important part of polyploid breeding to breed selectively diploid and to make the nonploidy mutation breeding.Polyploid and apomixis are used together,polyploid has significant value in creating new germ plasm and in studying inheritance.
出处
《西北植物学报》
CAS
CSCD
2003年第10期1829-1841,共13页
Acta Botanica Boreali-Occidentalia Sinica
关键词
同源四倍体
三倍体
遗传变异
育种
autotetraploid
triploid
inheritance-variation
breeding
