Tests of Taxonomic and Biogeographic Predictivity: Resistance to Disease and Insect Pests in Wild Relatives of Cultivated Potato

A major justifi cation for taxonomic and biogeographic research is its assumed ability to predict the presence of traits in a group for which the trait has been observed in only a representative subset of the group. Such predictors are regularly used by breeders interested in choosing potential sources of disease and pest resistant germ plasm for cultivar improvement, by genebank managers to organize the collection, and by germplasm collectors planning to gather maximum diversity. The present study tests taxonomic and biogeographic associations with 10,738 disease and pest evaluations, derived from the literature and genebank records, of 32 pest and diseases in fi ve classes of organisms (bacteria, fungi, insects, nematodes, and virus). The data show that ratings for only Colorado potato beetle [Leptinotarsa decemlineata (Say)] and one pathogen (Potato M Carlavirus) are reliably predicted both by host taxonomy and climatic variables. While it is logical to initially take both taxonomy and geographic origin into account while screening genebank materials for pest and disease resistances, such associations will hold for only for a small subset of resistance traits. Based on these results, a more effective strategy than taxonomic and biogeographic prediction is probably careful screening of core collections. D.M. Spooner and S.H. Jansky, USDA-ARS, Dep. of Horticulture, Univ. of Wisconsin, 1575 Linden Dr., Madison, WI 53706-1590; R. Simon, International Potato Center, P.O. Box 1558, La Molina, Lima 12, Peru. Received 18 Apr. 2008. *Corresponding author (david. [email protected]). Abbreviations: EBN, endosperm balance number; GIS, geographic information systems; RF, RandomForest method to test environmental associations; SVM, Support Vector Machine to test environmental associations. Published in Crop Sci. 49:1367–1376 (2009). doi: 10.2135/cropsci2008.04.0211 © Crop Science Society of America 677 S. Segoe 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.