Synthetic Hexaploids Derived from Wild Species Related to Sweet Potato
Synthetic Hexaploids Derived from Wild Species Related to Sweet Potato
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来自与甘薯相关的野生物种的合成六倍体
DOI：
10.1270/jsbbs1951.37.367
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发表时间：
1987
期刊：
影响因子：
--
通讯作者：
T. Kawase
中科院分区：
文献类型：
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作者：
I. Shiotani;T. Kawase
利用野生种质资源进行甘薯育种已有三十年的历史。这些尝试在提高甘薯的根产量、淀粉含量和抗线虫能力方面取得了显着的成果。一些多倍体系列野生植物可能具有许多对进一步改良农艺性状具有潜在重要意义的基因。然而，野生近缘种与六倍体甘薯（2n=6x=90）之间的基因组关系尚未揭示。对用二倍体和四倍体合成的六倍体以及在可能的情况下用甘薯合成的F1杂种进行了减数分裂研究。将花粉母细胞（PMC's）和根尖细胞中的染色体固定在New-comer's溶液中，并根据使用Schiff试剂的Feulgen反应进行染色。本报告涉及两种合成六倍体。第一个是由 Ipomoea lacunosa (K61, 2n=30) 和 I.tiliacea (K134, 2n=60) 之间三倍体杂交体的染色体加倍衍生的六倍体。合成的六倍体在中期 I 阶段 (MI) 表现出大部分规则的减数分裂和二价体，并且它被认为是同种异体或节段异体六倍体。合成的六倍体是可育的，但未能通过与甘薯杂交获得杂种表明它们之间存在关键的繁殖障碍。具有2x I，三裂(K221，2n=30)和4x I，三裂(K233，2n=60)的第二合成六倍体显示以四价和六价的出现为特征的染色体构型。这种多价关联的频率和每个细胞的数量都很高，表明基因组至少存在四份。在甘薯品种以及合成六倍体和甘薯之间的 F1 杂交种中观察到类似的染色体构型模式。因此，甘薯的基因组公式被提出为B1B1B2B2B2B2，其中B1B1赋予2x I.trifida，B2B2B2B2赋予4x I. trifida。然而，为了获得更确凿的甘薯基因组构成，有必要明确B1和B2基因组之间的同源程度。简要介绍了本研究中使用的野生番薯菌株的分类学鉴定。
The utilization of germplasm of the wild species in sweet-potato breeding has been conducted for the last three decades. Such attempts brought some remarkable achievments in improving root yield, starch content and resistance to the nematodes of sweet potato. Some wild plants in polyploid series may have many genes potentially important for further improvement of the agronomic traits. However, the genomic relationship between the wild relatives and hexaploid sweet potato (2n=6x=90) has been unrevealed. Meiotic studies were carried out on the hexaploids synthesized with diploids and tetraploids and on the F1 hybrids, when possible, with sweet potato. Chromosomes in pollen mother cells (PMC's) and root tip cells were fixed in New-comer's solution and stained according to Feulgen reaction with Schiff's reagent. The present report was concerned wlth two kinds of the synthetic hexaploids. The first was the hexaploids derived from chromosome doubling of triploid hybrids between Ipomoea lacunosa (K61, 2n=30) and I.tiliacea (K134, 2n=60). the synthetic hexaploid exhibited mostly regular meiosis with bivalents at the metaphase I stage (MI), and it was considered an allo- or segmental allo-hexaploid. The synthetic hexaploids were fertile, but failure in obtaining hybrids by crosses with sweet potato suggested a critical reproductive barrier between them. The second synthetic hexaploids with 2x I, trifida (K221, 2n=30) and 4x I, trifida (K233, 2n=60) showed the chromosome configurations characterized by the occurrence of tetravalents and hexavalents. Such multivalent associations, high in frequency and number per cell, suggested the presence of the genomes at least in quadruplicate. Similar pattern of the chromosome configura-tions was observed in a cultivar of sweet potato and the F1 hybrid between the synthetic hexaploid and sweet potato. Consequently, the genomic formula for sweet potato was proposed as B1B1B2B2B2B2, in which B1B1 was given to 2x I.trifida and B2B2B2B2 to 4x I. trifida. However, it is necessary to clarify the degree of homology between B1 and B2 genomes for more conclusive genomic constitution of sweet potato. A brief account was given for the taxonomic identification of the wild Ipomoea strains used in the present study.