GENETIC CONTROL OF CHROMOSOME PAIRING IN INTERGENERIC HYBRIDS WITH WHEAT
GENETIC CONTROL OF CHROMOSOME PAIRING IN INTERGENERIC HYBRIDS WITH WHEAT
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DOI：
10.1038/1831244a0
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发表时间：
1959-01-01
期刊：
影响因子：
64.8
通讯作者：
KIMBER, G
中科院分区：
文献类型：
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作者：
RILEY, R;CHAPMAN, V;KIMBER, G
Riley和Chapman[1381]以前对Holdfast的研究表明，普通小麦的二倍体减数分裂行为是由特定染色体上的一个基因控制的，称为HH。正如Sears和Okamoto[1098]所指出的，中国春的V染色体携带有负责限制同源配对的基因。然而，目前还不能确定染色体HH与中国春中的V是同源的。以期确定限制同源染色体配对的遗传控制是否存在。小麦染色体不能与相关属的一些种的染色体配对也是由普通小麦引起的，因此对经常发生的杂交进行了研究。普通‘中国春’单体V与长山羊草(2n=14)和‘国王II’。单体亲本产生n=21或20的配子，这取决于是否包括单个V染色体。因此，相同的♀亲本产生了2n=28或27的杂交后代，其中7条染色体来自♂配子。在28条染色体与Ae.每个细胞的二价体数量从未超过6个，平均只有1-96个。这种二价配对的程度只比整单倍体Holdfast略高一点。因为在单倍体互补OFAE中几乎没有同源性。Longissima，表明小麦与山羊草染色体之间存在少量配对现象。在27条染色体上与Ae.一价、二价、三价和四价的频率分别为：9.85±0.33，7.50±0.35；6.45±019，7.58±0.23；0.87±009，0.70±0.08；0.41±005，0.56±0.05。接合染色体数目的范围分别为10-24和10-27。单价体频率与HH非单倍体Holdfast(2n=20)的频率几乎相同，因此显然额外的7条染色体经常参与配对。与非单倍体相比，二价体的频率提高了一半以上，四价体的频率增加了20倍。与黑麦杂交的28条染色体的联结量并不高于整单倍体。尽管在与黑麦的27条染色体杂交中，一个细胞中可能有多达21条染色体参与配对，但平均而言，配对的染色体比HH非单倍体的霍尔德法斯特少。然而，这些27条染色体的杂交体的三价体数量与非单倍体大致相同，四价体的数量是非单倍体的四倍多。它们还含有一些由交叉伴生的大型复合体，涉及多达11条染色体。“大型复合体的产生可能是因为黑麦染色体和小麦同源群体之间并不存在严格的一对一关系[因为]黑麦染色体与小麦群体的染色体在易位上存在差异。”从育种的角度讨论了排除V染色体以减少小麦与其他属染色体配对障碍的意义，提出了利用27条染色体杂交种获得有利重组的途径。
Previous investigations on Holdfast by Riley and Chapman [1381] revealed that control of the diploid-like meiotic behaviour ofTriticum vulgarewas exercised by a gene on a particular chromosome, designated HH. As shown by Sears and Okamoto [1098], chromosome V in Chinese Spring carries the gene responsible for restriction of homeologous pairing. It has not however yet been possible to confirm that chromosome HH is homologous with V in Chinese Spring. With a view to determining whether the genetic control restricting pairing between homeologous chromosomes inT. vulgareis also responsible for the failure of wheat chromosomes to pair with those of some species in related genera, a study was made of crosses ofT. vulgare'Chinese Spring' monosomic V withAegilops longissima(2n= 14) andSécale céréale'King II'. The monosomic parents produced gametes withn= 21 or 20, depending on whether or not the single chromosome V was included. Consequently, the same ♀ parents gave rise to hybrids with2n= 28 or 27, seven of the chromosomes being derived from the ♂ gamete. In the 28-chromosome hybrid withAe. longissima, the number of bivalents per cell never exceeded 6, the mean being only 1-96. This degree of bivalent pairing is only slightly higher than in euhaploid Holdfast. Since little homology exists within the haploid complement ofAe. longissima, a small amount of pairing between wheat andAegilopschromosomes was indicated. In 27-chromosome hybrids withAe. longissima, the frequencies of univalents, bivalents, trivalents and quadrivalents in two lots of material were respectively: 9.85 ±0.33, 7.50 ±0.35; 6.45 ± 019, 7.58 ± 0.23; 0.87 ± 009, 0.70 ± 0.08; 0.41 ± 005, 0.56 + 0.05. The ranges in the number of chromosomes conjugating were respectively 10-24 and 10-27. Univalent frequency was almost the same as in HH nullihaploid Holdfast (2n= 20), so that evidently the seven extra chromosomes were often involved in pairing. Compared with the nullihaploid, the frequency of bivalents was increased by more than half and the quadrivalent frequency 20 times. The amount of association in the 28-chromosome hybrid with rye was not higher than in euhaploid Holdfast. Although as many as 21 chromosomes might be involved in associations in one cell in the 27-chromosome hybrids with rye, on the average fewer chromosomes were paired than in HH nullihaploids of Holdfast. These 27-chromosome hybrids had, however, about the same number of trivalents and more than four times as many quadrivalents as the nullihaploids. They also contained some large complexes, associated by chiasmata and involving up to 11 chromosomes. "The large complexes probably arose because there is not a strict one-to-one relationship between rye chromosomes and wheat homoeologous groups [because] the rye chromosomes differ from chromosomes of the wheat groups by trans-locations." The significance of reducing the barrier to the pairing of wheat chromosomes with those of other genera by excluding chromosome V is discussed from the point of view of breeding, ways in which 27-chromosome hybrids may be used to obtain favourable recombinations being suggested.