(二)缺体1.缺体的来源缺体主要来自3个途径。(1)单体自交产生缺体。前述单体植株平均大约有75％的 n-1雌配子和4％的 n-1雄配子可传递给后代,按此频率,单体自交便可产生3％的同类缺体,即1 A 单体自交便可产生相应的1 A 缺体。实际中,根据 Sears(1954)所累积的资料表明,在中国春单体系列的自交后代群体内,缺体数变化在0.9—7.6％之间,3B 和4A 较高,分别为7.6、6.4％,5D 和6B 最低,只有0.9％。(2)单等臂体、单端体自交后代产生缺体。其原理与单体自交产生缺体相同,所不同的是缺体出现频率较高。据 Sears(1954)对除4 B 和2 D 以外的14个单等臂体和15个单端体自交后代分析结果,发现除2B 单等臂、1B、5D 和7D 单端体因鉴定植株较 (B) the lack of body 1. The origin of the body missing bodies mainly from three ways. (1) monomer self-generated lack of body. An average of about 75% of the n-1 male gametes and 4% of the n-1 male gametes can be passed on to the progeny on the average. At this frequency, 3% Self-self-monomer can produce the corresponding 1 A lack of body. In fact, according to the data accumulated by Sears (1954), the numbers of missing individuals ranged from 0.9% to 7.6% in the selfing progeny population of Chinese Spring Monomer Series, while 3B and 4A were higher, which were 7.6, 6.4 %, 5D and 6B the lowest, only 0.9%. (2) Single arm, single-terminal self-generation offspring. The principle and monomer self-generated the same lack of body, the difference is the higher frequency of missing body. According to the results of Sears (1954) analysis of 14 single arm and 15 single-terminal inbred progeny other than 4 B and 2 D, it was found that 1B, 5D and 7D single- More