PHYSIOLOGY OF THE PEA CROP PHYSIOLOGY OF THE PEA CROP Book Coordinated by: Nathalie Munier-Jolain, Véronique Biarnès, Isabelle Chaillet, Jérémie Lecoeur, Marie-Hélène Jeuffroy With the collaboration of: Benoît Carrouée, Yves Crozat, Lydie Guilioni, Isabelle Lejeune, Bernard Tivoli CRC Press 6Su0i0te0 3B0ro0k, eBno Scoau nRda tPoanr,k FwLa y3, 3N4W87 Science Publishers Taylor & Francis Group 270 Madison Avenue an informa business N2 ePwar Yk oSrqk,u NarYe ,1 M00il1to6n Park Enfield, New Hampshire www.crcpress.com Abingdon, Oxon OX 14 4RN, UK Published by Science Publishers, P.O. Box 699, Enfield, NH 03748, USA An imprint of Edenbridge Ltd., British Channel Islands E-mail: [email protected] Website: www.scipub.net Marketed and distributed by: CRC Press 6Su0i0te0 3B0ro0k, eBno Scoau nRda tPoanr,k FwLa y3, 3N4W87 Taylor & Francis Group 270 Madison Avenue an informa business New York, NY 10016 2 Park Square, Milton Park www.crcpress.com Abingdon, Oxon OX 14 4RN, UK © 2010 reserved ISBN 978-1-57808-570-5 Published by arrangement with Editions Quae, Versailles French edition © INRA, ARVALIS-Institut du végétal, UNIP, ENSAM, 2005 ISBN (INRA) 2-7380-1182-9 ISBN (ARVALIS-Institut du végétal) 2-86492-679-2 ISSN 1144-7605 Library of Congress Cataloging-in-Publication Data Physiology of the pea crop. -- 1st ed. p. cm. "The French version of this book ([Paris, 2005]) has been co- ordinated by: Nathalie Munier-Jolain ... with the collaboration of: Benoît Carrouée ... [et al.]" Includes bibliographical references and index. ISBN 978-1-57808-570-5 (hardcover) 1. Peas--Physiology. 2. Peas--Research--France. I. Munier- Jolain, Nathalie. II. Carrouée, Benoît. QK495.L52P482 2009 635'.656--dc22 2009000071 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, electronic, mechanical, photocopying or otherwise, without the prior permission of the publisher, in writing. The exception to this is when a reasonable part of the text is quoted for purpose of book review, abstracting etc. This book is sold subject to the condition that it shall not, by way of trade or otherwise be lent, re-sold, hired out, or otherwise circulated without the publisher’s prior consent in any form of binding or cover other than that in which it is published and without a similar condition including this condition being imposed on the subsequent purchaser. Printed in the United States of America Preface Bertrand Ney and Benoît Carrouée This book covers all of the applied research carried out in recent years in France on protein peas. It is, however, in our view, more than simple description of progress in agronomic knowledge. It is also testimony to a process of innovation which has involved all the players in the industry. The eighties began with a new challenge for French and European agriculture—to make good the shortages in protein-rich plant products for animal feeding. In effect, soya seed and its cake monopolised the world protein market, whereas the livestock industry was expanding rapidly in France, and demand was growing. The embargo on soya in 1973 and the crisis which resulted in the animal sector quickly showed up the limitations of the European agricultural policy. The « protein plan » intended to promote a French production industry for protein-rich plant products was therefore decided upon in the conditions of the seventies and opened the way to European regulation in 1978. Among the candidate crops was the faba bean, the only protein crop traditionally grown in France for animal feeding, together with soya, pea, and somewhat later, lupin. Soya remained confined to the favourable conditions of the south of France. The white lupin, limited by its sensitivity to calcareous soils, and faba bean, limited by sensitivity to high temperatures, remained confined to the west and north of France. It was peas, hitherto grown in France as a forage for cattle or as a green legume for human food because of its high yield potential and its short growth cycle, which would prove to be the main support of a new industry in protein-rich products not based on oilseed cakes. From that moment, a new crop would emerge, made possible by the involvement of all the players in the industry: technical institutes (FNAMS, UNIP and ITCF, now called Arvalis-Institut du Végétal), research (INRA) and agronomy schools (Agro Paris Tech, Montpellier SupAgro , ESA Angers, ISA Beauvais etc.), public and private plant breeders, cooperatives and Chambers of Agriculture. Since 1985, these partners have met to confer together within the Pea Agrophysiology Group, on the initiative of UNIP (French Interprofessionnal Organisation of Protein Crops). The results of vi Physiology of the Pea Crop the first ten years’ work were recorded in the first book in 1994 which presented the state of knowledge on the vegetative and reproductive development of protein peas and their use in crop production. Important work by breeders has transformed peas from their former forage architecture (tall plants sensitive to lodging, with a large vegetative yield and an uncertain grain yield) to a stocky and highly branched leafless structure (the leaflets having been replaced by tendrils), which resists to lodging and is easily mechanically harvested, with grain of good size and quality. The crop however remains susceptible to diseases, especially in the north and west, where its abundant vegetative growth creates environmental conditions favourable to disease expression, notably anthracnose (Mycosphaerella pinodes), and to water and heat stress in the more continental or southerly regions. Thus it was found, using the first diagnostic tools introduced by the group, that, contrary to recent ideas, a pea crop, although nitrogen fixing, can suffer from nitrogen deficiency under the effects of early water stress, weevils whose larvae destroy the root system, or cultural practices leading to soil compaction. Likewise, its poor root system, in which it is now known that the roots and nodules compete markedly for the products of photosynthesis, accentuates water stress towards the end of growth and can limit yield. These factors, once identified as being liable to harm the crop, have been widely studied during the course of the last ten years and constitute very significant new contributions to this new edition. In spite of its sometimes undesirable characteristics, Solara, a leading variety registered in 1986 and an average ideotype suiting most situations, very rapidly took over the cultivated area. The area sown to peas reached nearly 750,000 ha at the beginning of the nineties. Along similar lines, to promote the crop on the European scale, the AEP (European Association for Grain Legumes Research) was founded in 1992 to bring together all the European players in the industry under the instigation of UNIP. However, from 1988 and the introduction of budgetary stabilisers, the successive reforms of the Common Agricultural Policy abandoned any will towards targeted development of protein crops : on the contrary, they decided (successfully) to stabilise the areas at the level reached at the end of the eighties in the EU. The pea-growing areas are therefore concentrated in the regions where the climate and the regulations make the crop most competitive. The frequent return of peas to the same fields in these regions during the nineties has led to the development of root diseases, in particular Aphanomyces, which causes very serious damage to peas. Many experienced pea growers in these regions have therefore had to abandon the crop for several years to decontaminate the fields, resulting in a marked reduction in the areas. Preface vii To cope with these problems, the players in the French industry have decided since the end of the nineties to concentrate on two major target objectives: (cid:129) To increase the areas of protein crops by diversifying the crops, with heavy investment in winter peas and faba beans ; (cid:129) To develop integrated projects, combining agronomy, genetics, pathology, animal husbandry and economics, in order to develop productive high quality pea ideotypes, more resistant to diseases (especially of the root), and also to evaluate the environmental impact of these innovations. The agreed efforts for the emergence of this new industry in Europe will not be in vain if one considers the new constraints which will certainly affect the agriculture of the future and the advantages of a crop like peas. This is a good response to the environmental problems and to the necessary diversification of crops for a better control of pathogenic agents, pests and weeds without excessive use of pesticides. The establishment of atmospheric nitrogen fixation from the beginning of crop growth makes the crop independent of nitrogenous fertilisers, which are heavy users of fossil energy and emitters of greenhouse gases. These environmental advantages can only be expressed by assuring optimal management of nitrogenous fertilisation and phytosanitary protection throughout the whole rotation and possibly by introducing a catch crop before or after the peas, whose growing period is very short. All the work contained in this book follows directly from its predecessor of 1994 and illustrates the dynamism of the partners in agricultural research and development. The new challenges assigned to agriculture demand the efforts of all those involved. The work presented here and what it represents bear clear testimony to this effort. Contents Preface v Preamble: Which approaches can be used to analyze pea................... xxi canopy physiology? Choice of approach ............................................................................ xxi A simple and generic analytical framework: the energy ......... xxii approach of biomass production Plant and pea crop representation mode...................................... xxiv Spring peas and winter peas ........................................................... xxv PART I: PEA CROP FUNCTIONING AND YIELD COMPONENTS 1. Vegetative development: The morphogenesis of ........................... 3 plant organs Introduction ......................................................................................... 3 Organisation of a pea stem .............................................................. 3 Functioning of the cauline meristem and the apical tip............ 6 Modelling foliar development ......................................................... 7 Modelling using the thermal time........................................................ 7 Foliar development from phytomere initiation to the end of ............ 9 leaf expansion The leaf from the unfolded stage to the senescence ............................. 9 Expansion of the vegetative organs ................................................ 10 Division then expansion of the cells .................................................... 10 Final size of vegetative organs ............................................................. 11 End of phytomere production ............................................................... 13 Conclusion ............................................................................................ 13 Floral initiation and the beginning of flowering ................................ 14 Definitions and observations ........................................................... 14 Floral initiation ...................................................................................... 14 Beginning of flowering .......................................................................... 14 Transition to the reproductive stage in pea ....................................... 15 Effects of photoperiod ............................................................................ 16 x Physiology of the Pea Crop Effects of temperature ............................................................................. 17 Effects of interaction between photoperiod and temperature ............ 18 Modelling “floral initiation” and “beginning of ....................... 19 flowering” Use of flowering date to identify genes responsible for ........... 19 the reaction to photoperiod Genetic variability of the length of the period from floral......... 21 initiation to the beginning of flowering Conclusion ............................................................................................ 21 Reproductive development ....................................................................... 23 Seed development ................................................................................ 23 Characterization of reproductive stages ....................................... 24 Which indicators? .................................................................................. 24 Beginning of seed filling or final stage in seed abortion ................... 25 End of seed filling period or physiological maturity ........................ 25 Whole plant reproductive development ....................................... 26 Rates of progression of reproductive stages along the stem .............. 26 Number of reproductive nodes .............................................................. 27 Duration of reproductive phases .......................................................... 27 How to represent whole plant development ................................ 28 diagrammatically? Branch emergence ....................................................................................... 30 Characteristics of pea architecture ................................................. 30 Initiation of meristems ....................................................................... 31 The number of meristems, a genotypic characteristic ........................ 31 Meristem initiation linked to the initiation of phytomers ................ 31 Initiation of phytomers .......................................................................... 32 Floral Initiation ...................................................................................... 32 Modelling the potential architecture .................................................... 33 Growth of branches ............................................................................ 33 The position of branches ........................................................................ 33 The number of branches.......................................................................... 34 The type of branches ....................................................................... ....... 34 R1 is an atypical branch ....................................................................... 34 Phyllochron of branches ........................................................................ 35 Flowering ................................................................................................ 36 Conclusion ............................................................................................ 36 Methodological sheet: measurements of developmental .................. 37 stages Measurements of stages at the stem scale ..................................... 37 Emergence ................................................................................................ 37 Contents xi Foliar stage: from emergence to the “Beginning of ............................ 37 flowering” stage Floral initiation ...................................................................................... 37 Beginning of flowering .......................................................................... 37 Flowering stage: from beginning to end of flowering......................... 38 Reproductive stages: from beginning to end of .................................. 39 final stage in seed abortion Physiological maturity .......................................................................... 41 Measurements of stages at the crop scale ..................................... 41 2. Carbon acquisition at the crop level in pea ....................................... 44 Introduction .......................................................................................... 44 Definition of the terms of Monteith’s equation ................................... 45 Radiative balance of a canopy ......................................................... 45 Radiation use efficiency RUE ............................................................... 46 Methods of estimation of the terms of Monteith’s equation ............ 47 Biomass determination ...................................................................... 47 Assessment of radiation absorption or ......................................... 47 interception efficiencies By means of measurements of the different components .................... 47 of the solar radiation balance By means of Beer’s law and the leaf area index .................................. 48 –LAI estimation ...................................................................................... 49 –Estimation of the radiation extinction coefficient ............................ 51 –Correspondence between RAE and RIE ............................................. 51 By means of measurements of structural or ......................................... 51 optical characteristics of the canopy RUE ......................................................................................................... 52 Variability sources of interception and absorption ........................... 52 efficiency during the cycle Change during the cycle .................................................................... 52 Effect of sowing date and density ................................................... 53 Genetic variability .............................................................................. 54 Sources of variability of radiation use efficiency ................................ 55 Variation during the cycle ................................................................ 55 Effect of sowing date and density.................................................... 56 Genetic variability ............................................................................... 57 Effects of environmental conditions .............................................. 58 Conclusion ............................................................................................ 59 xii Physiology of the Pea Crop 3. Dilution curve............................................................................................... 61 Plant N concentration in grain legume crops ............................. 62 in relation to developmental stage Determination of critical plant nitrogen concentration........... 63 for pea Determination of the « maximal » curve ....................................... 64 Hypothesis for the control of nitrogen uptake ............................ 66 by the plant Root and nodule establishment and associated carbon costs ........ 66 Root and nodule establishment ....................................................... 67 Establishment of the roots ..................................................................... 67 Nodules establishment and its modulation ......................................... 69 Carbon costs associated with structure establishment, ........... 71 maintenance and metabolism Carbon fluxes associated with the establishment and operation ...... 71 of the nodulated root system: C partitioning between shoot and root parts Carbon use within the root system as affected by the form of ........... 72 nitrogen nutrition Prospects ................................................................................................ 74 Nitrogen nutrition efficiency .................................................................... 74 Contribution of the two nitrogen uptake pathways .................. 74 to total N uptake by the plant during growth Complementarity between symbiotic N fixation and mineral ........ 74 2 N root absorption The two nitrogen uptake pathways have different kinetics and ....... 77 different sensitivities to environmental constraints N fixing activity as modulated by growth, phenology ............ 78 2 and nitrate N fixing activity as modulated by nitrate ......................................... 78 2 Time course of N fixing activity during the ...................................... 80 2 growth cycle N fixing activity depends upon nodule biomass .............................. 81 2 How to optimise and stabilise the nitrogen nutrition................ 82 of legumes? Methodologies for measuring symbiotic nitrogen fixation ................ 83 in the field Summary of measurement methods used in the ......................... 83 field to assess the percentage of N derived from atmospheric nitrogen fixation (%Ndfa) Three isotopic methods for calculating %Ndfa ........................... 84 Principle of isotopic methods ................................................................ 84