TAXONOMY OF ZEA (GRAMINEAE). I. A SUBGENERIC CLASSIFICATION WITH KEY TO TAXA
TAXONOMY OF ZEA (GRAMINEAE). I. A SUBGENERIC CLASSIFICATION WITH KEY TO TAXA
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DOI：
10.1002/j.1537-2197.1980.tb07730.x
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发表时间：
1980-07
影响因子：
3
通讯作者：
J. Doebley;H. Iltis
中科院分区：
文献类型：
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作者：
J. Doebley;H. Iltis
玉米属在此被分为Sect. LUXURIANTES Doebley & Iltis sect. n.，包括多年生植物Z. diploperennis（2n = 20）和Z. perennis（2n = 40）和一年生Z. luxurians（2n = 20）和ZEA组（包括野生Z. luxurians）。mays ssp.parviglumis和Z. Mays SSP. mexicana（均为2n = 20）和Z. Mays SSP.玉米（2n = 20），后者的高度驯化和巨大的可变衍生物。这种划分是通过对雄花序的大量形态特征进行多变量分析来验证的。细胞遗传学和化学分类学的证据支持形态学的结论。在这一新的属划分所提供的概念框架内，对玉米属的生殖发育的考虑令人信服地指向一年生大刍草（Z. Mays SSP.墨西哥）作为栽培玉米的祖先。根据最新的分类学处理（Iltis & Doebley，1980），玉米属（Zea）包括6个不同的分类群，分为4个种：1）Z.玉米属，广义上，包括Z. Mays SSP. mays，栽培玉米; Z. Mays SSP. mexicana（Schrader）Iltis，和Z. Mays SSP. parviglumis Iltis和Doebley，后两者是墨西哥和危地马拉中西部广泛分布的一年生大刍草; luxurians（Durieu and Ascherson）Bird，产于危地马拉东南部和洪都拉斯; perennis（Hitchc.）Reeves和Mangelsdorf，四倍体多年生大刍草; diploperennis Iltis、Doebley和Guzmain，最近发现的二倍体多年生大刍草，后两个都是墨西哥南部哈利斯科的高度本地物种。这些分类群可以安排亚属在几个方面，这取决于一个人的标准。因此，如果一个人遵循迄今为止出版的唯一分类系统（Post和Kuntze 1903; cf. Wilkes，1967），该属将被划分为ZEA组，只包含栽培种Z。mays sensu stricto和Euchlaena（Schrader）Kuntze组，包含所有五个剩余的分类群，即大刍草。我于1979年10月19日收到出版物; 1979年12月19日接受修订。对这项工作的部分支助是赠款（给H.H.I.）来自NSF（BM S74-21861），研究生院研究委员会，戴维斯基金会和0。N.艾伦植物标本馆基金，植物系，威斯康星大学麦迪逊分校，和先锋国际育种公司。我们感谢国际玉米和玉米加工中心（CIMMYT）的Donald Duvick、Robert科瓦尔、Walton Galinat、Frederick J. Hermann、Karen Lind、Norman Borlaug和琳达安斯沃思在本研究的各个方面提供的帮助和支持，特别感谢Maria L. Puga，Rafael Guzman M.，Enrique Estrada F.，和墨西哥瓜达拉哈拉大学植物学院。约翰·朗奎斯特种植了我们的大部分材料。D. Davidse，F. G. Gould和T. Soderstrom对手稿提出了有益的评论。分裂是显而易见的。首先，不仅玉米的巨大的、多列的、多种子的、不脱节的雌性穗在仙女草族（或者，就此而言，在禾本科）中是完全独特的，而且所有大刍草属物种的细长的、二列的、少种子的、脱节的雌性穗彼此如此相似，以至于几乎无视分类学上的区分。雄穗和雄花序也是如此。玉米雄穗总是容易通过其厚且高度浓缩的中心（末端）穗（即，每单位长度具很多小穗），相反的侧枝总是纤细和不浓缩。另一方面，大刍草的雄穗有均匀纤细和不密集的分枝，中央（顶生）穗状花序几乎不与侧枝分化。事实上，有经验的“大刍草猎人”只要用双筒望远镜扫视玉米地“天际线”，寻找玉米穗的中央分支，很快就能学会在相当远的距离从车窗里分辨出大刍草和玉米。如果不浓缩和细长，它是大刍草;如果硬和厚，它是玉米！因此，简单地在雄性和雌性花序中的小穗排列的基础上，Kuntze的分类划分似乎是正确的和无懈可击的。尽管玉米穗具有独特性，但任何将人类欲望的对象归入一个亚属类别，而将其所有野生亲属归入另一个亚属类别的经济属分类，先验地都是值得怀疑的。换句话说，我们可以说，作为一个一般原则，经济属的基本系统分类决不应该主要基于那些由人类故意选择的形态特征。这样做会导致一种分类学，即通常大而多种子的品种被置于
The genus Zea is here divided into the Sect. LUXURIANTES Doebley & Iltis sect. n., including the perennials Z. diploperennis (2n = 20) and Z. perennis (2n = 40) and the annual Z. luxurians (2n = 20); and Sect. ZEA, including the wildZ. mays ssp.parviglumis andZ. mays ssp. mexicana (both 2n = 20), and Z. mays ssp. mays (2n = 20), the highly domesticated and tremendously variable derivate of the latter. This division is verified by a multivariate analysis of a large number of morphological characters of the male inflorescence. Cytogenetic and chemotaxonomic evidence supports the morphological conclusions. A consideration of the phylogeny of Zea within the conceptual framework offered by this new sectioning of the genus points convincingly to annual teosinte (Z. mays ssp. mexicana) as the ancestor of cultivated maize. THE GENUS Zea contains, according to its latest taxonomic treatment (Iltis & Doebley, 1980), six distinct taxa classified into four species: 1) Z. mays L., sensu lato, including Z. mays ssp. mays, the cultivated maize; Z. mays ssp. mexicana (Schrader) Iltis, and Z. mays ssp. parviglumis Iltis and Doebley, the latter two the widespread annual teosintes from Mexico and west central Guatemala; 2) Z. luxurians (Durieu and Ascherson) Bird, the annual teosinte from southeastern Guatemala and Honduras; 3) Z. perennis (Hitchc.) Reeves and Mangelsdorf, the tetraploid perennial teosinte; and, finally, 4) Z. diploperennis Iltis, Doebley and Guzmain, the recently discovered diploid perennial teosinte, the latter two both highly local species from southern Jalisco, Mexico. These taxa could be arranged subgenerically in several ways, depending on one's criteria. Thus, if one follows the only taxonomic system so far published (Post and Kuntze 1903; cf. Wilkes, 1967), the genus would be divided into Sect. ZEA, containing only the cultigenZ. mays sensu stricto, and Sect. EUCHLAENA (Schrader) Kuntze, containing all five remaining taxa, the teosintes. The reasons the genus was thus I Received for publication 19 October 1979; revision accepted 19 December 1979. Support for this work provided in part by grants (to H.H.I.) from NSF (BM S74-21861), the Research Committee of the Graduate School, the Davis Fund and the 0. N. Allen Herbarium Fund, Department of Botany, University of Wisconsin-Madison, and Pioneer Hi-Bred International, Inc. For help and support with various aspects of this research our thanks go to Donald Duvick, Robert Kowal, Walton Galinat, Frederick J. Hermann, Karen Lind, Norman Borlaug, and Linda Ainsworth of the Centro Internacional de Mejoramiento de Maiz y Trigo (CIMMYT); and especially to Maria L. Puga, Rafael Guzman M., Enrique Estrada F., and the Instituto de Botanica, Universidad de Guadalajara, Mexico. John Lonnquist grew much of our material. D. Davidse, F. G. Gould and T. Soderstrom made helpful comments on the manuscripts. divided are obvious enough. First, not only are the gigantic, polystichous, many-seeded, nondisarticulating female ears of maize totally unique in the Andropogoneae (or, for that matter, in the Gramineae), but the slender, distichous, few-seeded, disarticulating female spikes of all teosinte species are so similar to each other as to nearly defy taxonomic discrimination. Similarly with the tassel, the male inflorescence. Maize tassels are always easily recognized by their thick and highly condensed central (terminal) spike (i.e., with many spikelets per unit length), the lateral branches in contrast being always slender and uncondensed. Teosinte tassels, on the other hand, have uniformly slender and uncondensed branches, with the central (terminal) spike scarcely if at all differentiated from the lateral branches. As a matter of fact, experienced "teosinte hunters" can soon learn to distinguish teosinte and maize from a car window at quite some distance by scanning the cornfield "skyline" with binoculars and looking for the central branch of the tassel. If uncondensed and slender, it's teosinte; if stiff and thick, it's maize! Thus, simply on the basis of spikelet arrangement in both male and female inflorescences, Kuntze's taxonomic division would seem, on the face of it, to be correct and unassailable. The uniqueness of the maize ear notwithstanding, any classification of an economic genus which places the object of human desire into one subgeneric category and all its wild relatives in another is, a priori, open to suspicion. In other words, we may state as a general principle that the fundamental systematic classification of economic genera should never be based primarily on those morphological features deliberately selected for by man. To do so leads to a taxonomy where the generally largeand many-seeded cultivars are placed in