Authors: S Kazi J Shultz J Afzal J Johnson V N Njiti D A Lightfoot
Publish Date: 2008/03/07
Volume: 116, Issue: 7, Pages: 967-977
Abstract
Soybean Glycine max L Merr cultivars show differences in their resistance to both the leaf scorch and root rot of sudden death syndrome SDS The syndrome is caused by root colonization by Fusarium virguliforme ex F solani f sp glycines Root susceptibility combined with reduced leaf scorch resistance has been associated with resistance to Heterodera glycines HG Type 1367 race 14 of the soybean cyst nematode SCN In contrast the rhg1 locus underlying resistance to Hg Type 0 was found clustered with three loci for resistance to SDS leaf scorch and one for root infection The aims of this study were to compare the inheritance of resistance to leaf scorch and root infection in a population that segregated for resistance to SCN and to identify the underlying quantitative trait loci QTL “Hartwig” a cultivar partially resistant to SDS leaf scorch F virguliforme root infection and SCN HG Type 1367 was crossed with the partially susceptible cultivar “Flyer” Ninetytwo F5derived recombinant inbred lines and 144 markers were used for map development Four QTL found in earlier studies were confirmed One contributed resistance to leaf scorch on linkage group LG C2 Satt277 P = 0004 R 2 = 15 Two on LG G underlay root infection at R8 Satt038 P = 00001 R 2 = 281 Satt115 P = 0003 R 2 = 129 The marker Satt038 was linked to rhg1 underlying resistance to SCN Hg Type 0 The fourth QTL was on LG D2 underlying resistance to root infection at R6 Satt574 P = 0001 R 2 = 10 That QTL was in an interval previously associated with resistance to both SDS leaf scorch and SCN Hg Type 1367 The QTL showed repulsion linkage with resistance to SCN that may explain the relative susceptibility to SDS of some SCN resistant cultivars One additional QTL was discovered on LG G underlying resistance to SDS leaf scorch measured by disease index Satt130 P = 0003 R 2 = 13 The loci and markers will provide tagged alleles with which to improve the breeding of cultivars combining resistances to SDS leaf scorch root infection and SCN HG Type 1367This research was funded over the past 11 years in part by grants from the NSF 9872635 ISA 9512204 9812202 and 0212703 and USB 22286228 The integrated genetic and physical map was based upon work supported by the National Science Foundation under Grant No 9872635 Any opinions findings and conclusions or recommendations expressed in this material were those of the authors and do not necessarily reflect the views of the National Science Foundation The continued support of SIUC College of Agriculture and Office of the Vice Chancellor for Research to SK JA and DAL was appreciated The authors thank Dr P Gibson O Myers Jr and M Schmidt for assistance with germplasm development and maintenance from 1991 to 2000 and Dr Rizwan Hashmi for assistance with data analysis and interpretation
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