Selection for increased numbers of extra heterochromatic chromosomes in the tomato.
Selection for increased numbers of extra heterochromatic chromosomes in the tomato.
复制标题
选择增加番茄中额外异染色质的数量。
DOI：
10.1093/genetics/84.1.43
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发表时间：
1976
期刊：
影响因子：
3.3
通讯作者：
C. Quiros
中科院分区：
文献类型：
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作者：
C. Quiros
将两个携带两种类型的额外染色体的亲本植株2n+2（5L*7S）与2n+3（2S*2S）杂交，允许在后代中有效地选择具有多达8条2S*2S染色体的个体。2n + 3（2S × 2S）与2n+1（8 S × 8L）及野生番茄近缘二倍体L. pimpinellifolium，产生的植物多达四个额外的染色体。两个配子体对2S*2S染色体的耐受性至少有四个额外的。2 ~ 8条2S*2S染色体的存在使花粉育性降低82%~ 41%。后代检测表明，2S*2S染色体在传递中有丢失的趋势。25、26、27、28、29和30条染色体的自交后代平均染色体数分别为24.3、25.1、25.5、27.1、28.2和27.9条。二倍体和染色体外植物杂交的后代表现出类似的趋势。显然，番茄2S*2S染色体缺乏一些具有天然存在的辅助染色体的植物物种的积累特征的机制。额外的2S*2S染色体在有丝分裂中非常稳定，并且不会从未修饰植物的体细胞组织中消除。某些植物的严重修剪会导致这些染色体的丢失或获得。本文还讨论了通过增加2S*2S染色体在细胞中积累2 ~ 18个核仁组成区的重要性。
Crossing two parental plants carrying two types of extra chromosomes, 2n+2(5L*7S) by 2n+3(2S*2S) permitted effective selection for individuals with up to eight 2S*2S chromosomes in later generations. The crossing of 2n + 3(2S*2S) by 2n+1( 8S*8L) and by the wild tomato relative, diploid L. pimpinellifolium , produced plants with up to four extra chromosomes. The tolerance of 2S*2S chromosomes through both gametophytes is at least four extras. The presence of two to eight extra 2S*2S chromosomes decreased pollen fertility between 82 to 41%. Progeny tests reveal that 2S*2S chromosomes tend to be lost in transmission. Progenies of self-pollinated individuals with 25, 26, 27, 28, 29 and 30 chromosomes averaged 24.3, 25.1, 25.5, 27.1, 28.2 and 27.9 chromosomes respectively. The offspring of crosses between diploid and extrachromosomal plants showed similar tendencies. Evidently tomato 2S*2S chromosomes lack the mechanisms for accumulation characteristic of some plant species with naturally occurring accessory chromosomes.-Extra 2S*2S chromosomes are very stable mitotically and are not eliminated from the somatic tissue of unmodified plants. Severe pruning of certain plants induced loss or gain of these chromosomes.-The importance of accumulating two to 18 nucleolar organizer regions in a cell by addition of 2S*2S chromosomes is discussed.