Genus Medicago (Leguminosae) a Taxogenetic Study
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GENUS MEDICAGO GENUS MEDICAGO (LEGUMINOSAE) A TAXOGENETIC STUDY KARLIS ADOLFS LESIN8 & IRMA LESINS Dr. W. Junk bv Publishers The Hague-Boston-London 1979 The distribution of this book is handled by the following team of publishers: for the United States and Canada Kluwer Boston, Inc. 160 Old Derby Street Hingham, MA 02043 USA for all other countries Kluwer Academic Publishers Group Distribution Center P.O. Box 322 3300 AH Dordrecht The Netherlands Library of Congress Cataloging in Publication Data Lesins, Karlis Adolfs. Genus Medicago: (Leguminosae): a taxogenetic study. Bibliography: p. Includes index. 1. Medicago. 2. Botany-Classification. 3. Plant genetics. L Lesins, Irma, joint author. II. Title. QK495.L52L42 583'.322 79-18960 ISBN-13:978-94-009-9636-6 e-ISBN-13:978-94-009-9634-2 DOl: 10.1007/978-94-009-9634-2 Cover design Max Velthuijs Copyright © 1979 Dr. W. Junk bv Publishers, The Hague. So/trover reprint 0/ the hardcaver 1st edition 1979 All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, mechanical, photocopying, recording, or otherwise, without the prior written permission of the publishers Dr. W. Junk bv Publishers, P.O. Box 13713, 2501 ES The Hague, The Netherlands. CONTENTS INTRODUCTION IX ACKNOWLEDGEMENTS XI GENERAL PART 1 PROCEDURAL 3 NOTES TO ITEMS OF SPECIFIC PART 9 Keys and Grouping 9 Description 10 Taxon's name and authorship 10 Growth habit and longevity 10 Hairiness of aboveground vegetative parts 11 Inflorescence and adjacent parts 11,12,* 14, 19 (color pI. I) Fruits (pods) 17,20 Seeds 24,24,25,26 Pollen 28,28,29 Chromosome number 30, 31 (tbi. I) HABITAT AND DISTRIBUTION 31 Habitat 31,35 (color pI. IT) Distribution 33 INTRASPECIFIC VARIATIONS, DISTINGUISHING FEATURES BETWEEN AND RELATIONSHIP TO OTHER SPECIES 35 AGRICULTURAL VALUE 36 ISOLATING MECHANISMS, SPECIATION, EVOLUTION IN MEDICAGO, RELATIONSHIP TO OTHER GENERA 38 ISOLATING MECHANISMS 38 Ploidy and chromosome rearrangement 38 Other isolating mechanisms 39 FACTORS IN SPECIATION, GENERAL 43 Environmental stress 43 Time allowed for evolutionary changes 45 Previous history of development 45 * In General Part italics refer to figures, or pages facing color plates V EVOLUTION IN MEDICAGO 46 RELATIONSHIP TO OTHER GENERA 53,54 SPECIFIC PART 59 GENUS MEDICAGO, AND KEY TO SUBGENERA 61 GENERAL KEY TO MEDICAGO SPECIES 62 Subgenus Lupularia, and key to species 66 M.lupulina 67 M. secundiflora 70 Subgenus Orbicularia, and key to sections 72 Section Carstiensae 72 M. carstiensis 72 Section Platycarpae, and key to species 74 M. platycarpa 75 M. ru thenica 77 Section Orbiculares 79 M. orbicularis 79 Section Hymenocarpos 81 M. radiata 81 Section Heynianae 84 M. heyniana 84 Section Cretaceae 86 M. cretacea 86 Subgenus Medicago, and key to sections 86 Section Falcago, and key to subsections 87 Subsection Falcatae, and key to species 87 M. falcata 90 M. sativa 95,97 (color pI. III), 100 (tbl. IT) M. giomerata 108 M. giutinosa 112 M. prostrata 113 Subsection Rupestres, and key to species 116 M. rhodopea 117 M. saxatilis 117 M. rupestris 119 M. cancellata 120 Subsection Daghestanicae, and key to species 121 M. daghestanica 121 M. pironae 124 Subsection Papillosae, and key to species 125 M. dzhawakhetica 125 M. papillosa 129 VI Section Arboreae 131 M. arborea 131 Section Marinae 133 M. marina 134 Section Suffruticosae, and key to species 134 M. suffruticosa 135 M. hybrida 139 Subgenus Spirocarpos, and key to sections 140 Section Rotatae, and key to species groups 141 M. rotata 143 M. bonarotiana 145 M. noiiana 147 M. shepardii 150 M. rugosa 150 M. scutellata 152 Section Pachyspirae, and key to species groups 154 M. soleirolii 154 M. tornata 156 M. littoralis 162 M. truncatula 166, 167 (tbl. ill) M. rigidula 170 M. murex 173 M. constricta 176 M. turbinata 179 M. doUata 181 Section Leptospirae, and key to species groups 183 M. sauvagei 185 M. laciniata 187 M. minima 190 M.praecox 191 M. coronata 193 M. polymorpha 196 M. arabica 199 M.lanigera 201 M. disciformis 203 M. tenoreana 205 Section Intertextae, and key to species 207 M. intertexta 209 M. ciliaris 210 M. muricoleptis 211 M.granadensis 214 REFERENCES 216 INDEX to plant genera, sections, species and hybrids not listed in contents 226 VII INTRODUCTION In introducing ourselves it should be told that in our native Latvian language our name is written LesiJ;l.s. In most English publications, as in this work, the writing has been simplified to Lesins, and often only the first initial has been used. Our interest in Medicago was first aroused during 1936-38, while em ployed as teachers in the agricultural and home economics school at Be brene, Upper Zemgale, Latvia. Some plants of alfalfa (M. varia, M. media), locally called 'lucema', were found growing wild along roadsides in that area, though no alfalfa fields had been seen in the vicinity within the me mory of local farmers. Some roadside plants were dug out and transplanted to the garden, but their seedset was poor. During the next few years we paid only slight attention to alfalfa, the reason being that Latvia is a country with Atlantic climatic features (annual precipitation 600-700 mm; mild win ters for its 56°-58° N. Lat., with January isotherms between -3° and -7° C; moderately warm summers, with July isotherms between 16° and 18° C), which together with its soils, mostly of acidic, podzolic type, is not well suited for alfalfa production. It was not until 1945 in Sweden that work on alfalfa came to the foreground, when the senbor author was assigned investi gations on alfalfa seed setting by Dr. Erik Akerberg, then director of the Swedish Seed Association branch station at ffituna. The junior author, Irma Lesins, soon joined the project. Conditions at Ultuna were more suitable for alfalfa growing, as the soils were neutral. Moreover, alfalfa seed setting investigations were and still are a tradition at that institution as a continua tion of studies by its former director, R. Torssell (1936, 1943, 1948). Our results confirmed the earlier findings that good seedset in alfalfa required cross-pollination, that honey bees were not effective cross-pollinators, and that there were too few wild bees to provide cross-pollination necessary for a good seedset (Lesins, 1950). An intensive search for means to improve the seed setting situation followed. In one direction we looked for related taxa that were self-fertile and could be hybridized with alfalfa, thus transferring self-fertility to the cultivated crop. In another direction, noting that self opening of florets (self-tripping) in alfalfa under certain conditions was quite common, we searched for plants that, after self-tripping and, conse quently, after self-pollination and self-fertilization, would not suffer dras tically from inbreeding depression. Following the first approach, i.e., hybridization, a prerequisite for fur ther work was the acquisition of as many different Medicago species as possible, and also of some Trigonella and Melilotus. In addition, techniques for determining chromosome number, duplicating chromosome sets, as well IX as embryo culture, grafting and hybridization had to be adjusted for our material or developed anew. In the other direction, the search for inbreed ing-tolerant plant material was encouraged following the observation that progenies from certain plants suffered much less from inbreeding depression than others. Studies on inheritance of some plant characters were also started at Uituna. Since 1951, at the University of Alberta (Edmonton, Canada), the above mentioned studies have been continued and extended. The aim was set to acquire all known Medicago species and as many varieties as possible. Un fortunately, from botanical institutions and gardens only the most common species were available and even these under confusingly different names. It soon became obvious that without field expeditions we would never come close to achieving a complete collection of all Medicago species. After the first expedition to Italy in 1959, the idea of systematically investigating and compiling the results in a Medicago monograph was first conceived. However, a number of countries or districts harboring certain rare endemic species were out of our reach. We are greatly indebted to those botanists (only a few of whom are mentioned in the acknowledgements) who have supplied us with live seeds from those areas. With the accumula tion of live Medicago material, and an aim set for its systematization, all aspects concerning different Medicago taxa became of interest. Gradually much of the time and effort invested in improvement of cultivated alfalfa shifted to systematization of accumulated Medicago material, though inter est in alfalfa improvement was never left out of sight. As time went on some specialization in duties between the two authors was worked out. Morpho logical notes with the thousands of necessary measurements, together with some of the chromatography and cytology, fell to the junior author, who had completed about nine-tenths of the morphological descriptions when she died in 1966. The senior author's responsibility was hybridization and genetic studies together with the alfalfa breeding work. The results, of which this book represents the final outcome, have appeared in part in a number of co-authored papers. Throughout this book the term 'we' is used to express the fact that ideas and items were discussed by both authors from the early stages. The final formulations are those of the senior author. x ACKNOWLEDGEMENTS The authors are indebted to both the Swedish Seed Association and the University of Alberta for facilities provided during the different phases of this work from 1945 to the present (1979). Grants made either directly to the authors or through directors of the institutions concerned have been received from the Wenner-Grens, Helge Axelsson-Johnsson, and the Harvie foundations, the National Research Council of Canada, the Alberta Wheat Pool, the Alfalfa Processors Co-op Association (Alberta), the Canada De partment of Agriculture, the Alberta Agricultural Research Trust, and the Scientific Division of NATO.