Department of Biochemistry, Purdue University, 47907, West Lafayette, IN, USA.
Theor Appl Genet. 1990 Jun;79(6):737-47. doi: 10.1007/BF00224238.
Genetic variants were found among over 6,000 primary plants (R1) regenerated from embryogenic tissue cultures of eight high tannin sorghums [Sorghum bicolor (L.) Moench]. Field assessment of somaclonal variation has progressed to the R2 population, with over 48,000 R2 seedlings (27,000 plants) in 1,126 rows from 1,055 R1 plants. A total of 43 variant phenotypes was recovered, including several types of chlorophyll deficiencies, dwarfism, short culm, sterility, narrow leaf, and several previously unreported variants, such as ragged leaf, multibranched heads, and Hydra, a developmental variant which produces large numbers of panicles. Variation production greatly depends on parent genotype and appears to increase with increasing time in cultures. The toal average somaclonal variation rate (based per 100 R1 plants) and somaclonal variant frequency (based per 100 R2 plants) estimated in the tested population were 11.3 and 1.6, respectively. Chimerism was found in regenerants. The estimated size of the mutated sector carried by mutant regenerants ranged from the whole plant to less than 3% of a single head. The average proportion of mutated R1 heads carrying large (80%-100%), medium (40%-80%), and small (<40%) mutated sectors was 38.7%, 26.0% and 35.3%, respectively. Some sector mutations do not appear until the R3 generation. In order to avoid losing variants, the population for selecting somaclonal variation should be as large as possible. Some of these variants found may be useful for further study or for use in breeding programs.
在从 8 种高单宁高粱 [高粱（L.）Moench] 的胚性组织培养物中再生的 6000 多个初级植物（R1）中发现了遗传变异。体细胞变异的田间评估已经进展到 R2 群体，在 1055 个 R1 植物中，有超过 48000 个 R2 幼苗（27000 株）在 1126 行中。共回收了 43 种变异表型，包括几种类型的叶绿素缺乏、矮化、短茎、不育、窄叶，以及几种以前未报道的变异，如锯齿叶、多分枝头和 Hydra，这是一种产生大量花序的发育变异。变异的产生在很大程度上取决于亲本基因型，并且似乎随着培养时间的增加而增加。在测试种群中，估计的总体细胞变异率（基于每 100 个 R1 植物）和体细胞变异频率（基于每 100 个 R2 植物）分别为 11.3 和 1.6。在再生体中发现了嵌合体。突变再生体携带的突变体扇形的估计大小从整个植物到不到单个头部的 3%不等。携带大（80%-100%）、中（40%-80%）和小（<40%）突变扇形的平均比例分别为 38.7%、26.0%和 35.3%。有些扇形突变直到 R3 代才出现。为了避免丢失变异，选择体细胞变异的群体应尽可能大。发现的一些变异可能对进一步研究或用于育种计划有用。
