caa a22 4500 397521316 CHVBK 20180308164633.0 cr unu---uuuuu 161202e199507 xx s 000 0 eng 10.1093/jxb/46.7.853 doi (NATIONALLICENCE)oxford-10.1093/jxb/46.7.853 Identification of QTL for drought responses in maize and their use in testing causal relationships between traits [Elektronische Daten] [C. Lebreton, V. Lazić-Jančić, A. Steed, S. Pekić, S.A. Quarrie] A difficulty in identifying traits that help crop plants maintain their yield under droughted conditions is distinguishing between those traits that contribute to yield stability under drought and traits that do not affect yield. With the development of molecular markers for many crops it is now possible to identify major quantitative trait loci (QTL) regulating specific drought responses. By comparing the coincidence of such QTL for specific traits it is possible to test much more precisely than before whether a particular constitutive or adaptive response to drought stress is likely to be of significance in improving drought resistance. We have used this approach to identify QTL for ABA content and other traits likely to be important in determining drought response in maize. Eighty-four RFLP markers were mapped in an F2 population of 81 plants from a cross between parents, Polj17 (drought resistant) and F-2 (drought sensitive), that differ markedly in many constitutive and adaptive responses to drought stress. In a soil glasshouse experiment, from which water was withheld for 3 weeks after anthesis, flowering time, stomatal conductance, tissue ABA contents, leaf water relations parameters and fluorescence characteristics, root pulling force, and nodal root number were measured. The minimum number and location of genes having major effects on the traits were determined and possible causal relationships amongst them tested. Comparing the coincidence of QTL for ABA content and stomatal conductance showed that xylem ABA content was more likely to have had a regulatory effect on the stomatal conductance of those plants than the whole leaf ABA content. However, both xylem and leaf ABA contents were significantly associated with root characteristics, suggesting that the rooting behaviour (either constitutive or adaptive) was important in regulating stress responses, particularly in determining xylem ABA contents. We also found that Fm (a measure of the activity of photosynthetic reaction centres) was positively associated with chlorophyll concentration per unit area. Different methods for comparing QTL are presented and discussed. © Oxford University Press Research Papers nationallicence Quantitative trait loci (QTL) nationallicence ABA content nationallicence rooting behaviour nationallicence fluorescence characteristics nationallicence drought responses nationallicence maize nationallicence Lebreton C. John Innes Centre, Norwich Research Park Colney, Norwich NR4 7UH, UK aut Lazić-Jančić V. Maize Research Institute Slobodana Bajica 1, Zemun Polje, 11081 Belgrade-Zemun, Serbia aut Steed A. John Innes Centre, Norwich Research Park Colney, Norwich NR4 7UH, UK aut Pekić S. Faculty of Agriculture, University of Belgrade Nemanjina 6, 11081 Belgrade-Zemun, Serbia aut Quarrie S.A. John Innes Centre, Norwich Research Park Colney, Norwich NR4 7UH, UK aut Journal of Experimental Botany Oxford University Press 46/7(1995-07), 853-865 0022-0957 46:7<853 1995 46 exbotj https://doi.org/10.1093/jxb/46.7.853 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1093/jxb/46.7.853 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Lebreton C. John Innes Centre, Norwich Research Park Colney, Norwich NR4 7UH, UK aut NATIONALLICENCE 700 1- Lazić-Jančić V. Maize Research Institute Slobodana Bajica 1, Zemun Polje, 11081 Belgrade-Zemun, Serbia aut NATIONALLICENCE 700 1- Steed A. John Innes Centre, Norwich Research Park Colney, Norwich NR4 7UH, UK aut NATIONALLICENCE 700 1- Pekić S. Faculty of Agriculture, University of Belgrade Nemanjina 6, 11081 Belgrade-Zemun, Serbia aut NATIONALLICENCE 700 1- Quarrie S.A. John Innes Centre, Norwich Research Park Colney, Norwich NR4 7UH, UK aut NATIONALLICENCE 773 0- Journal of Experimental Botany Oxford University Press 46/7(1995-07), 853-865 0022-0957 46:7<853 1995 46 exbotj Metadata rights reserved CC BY-NC-4.0 http://creativecommons.org/licenses/by-nc/4.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-oxford