Genetic Architecture of Phosphorus Use Efficiency in Tropical Maize Cultivated in a Low-P Soil

TLDR: Evaluating the genetic architecture of PUE in tropical maize using multiple interval mapping for design III in a population of 140 RILs backcrossed with both parental lines showed that dominance effects were more important than additive effects for explaining the variations in PUE and its components.

Abstract: Phosphorus (P) deficiency is a major limiting factor for crop production in several countries. A better understanding of the genetic components of P use efficiency (PUE) is required to improve crop performance in low-P soils. To date, no QTLs (quantitative trait loci) were mapped for PUE using grain yield and other late phenotypic data in tropical conditions. Thus, we evaluated the genetic architecture of PUE in tropical maize (Zea mays L.) using multiple interval mapping for design III in a population of 140 RILs (recombinant inbred lines) backcrossed with both parental lines. The parental lines contrasted for yield and for PUE, a phenotypic index that was further decomposed into P acquisition efficiency (PAE) and P utilization efficiency. Our results showed that dominance effects were more important than additive effects for explaining the variations in PUE and its components. Approximately 80% of the QTLs mapped for PAE co-localized with those for PUE, indicating that the efficiency in acquiring P is the main determinant of PUE in tropical maize. Also, QTLs for PUE and PAE were located near to candidate genes previously associated with root development. Thus, we present important information to guide breeding strategies for the development of maize cultivars more adapted to P deficiency. F.F. Mendes, C.T. Guimaraes, L.J.M Guimarães, P.E.O. Guimarães, J.V. Magalhaes, and S.N. Parentoni, Embrapa Milho e Sorgo, CP 285, 35701970, Sete Lagoas, MG, Brazil; J.C. Souza, Dep. de Biologia, Univ. Federal de Lavras, CP 37, 37200-000, Lavras, MG, Brazil; A.A.F. Garcia, Dep. de Genética, Escola Superior de Agricultura Luiz de Queiroz, Univ. de São Paulo CP 83, 13400-970, Piracicaba, SP, Brazil. Received 14 Nov. 2013. *Corresponding author (claudia.guimaraes@embrapa.br). Abbreviations: GY, grain yield; LOD, logarithm of odds; MIM, multiple interval mapping; PAE, phosphorus acquisition efficiency; Psoil, phosphorus soil content; PUE, phosphorus use efficiency; PUTIL, phosphorus internal utilization efficiency; QTL, quantitative trait loci; RIL, recombinant inbred line; SDW, shoot dry weight. Published in Crop Sci. 54:1530–1538 (2014). doi: 10.2135/cropsci2013.11.0755 Freely available online through the author-supported open-access option. © Crop Science Society of America | 5585 Guilford Rd., Madison, WI 53711 USA All rights reserved. No part of this periodical may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or any information storage and retrieval system, without permission in writing from the publisher. Permission for printing and for reprinting the material contained herein has been obtained by the publisher. Published April 28, 2015