Authors: Henry Terán Shree P Singh
Publish Date: 2009/01/25
Volume: 167, Issue: 3, Pages: 271-280
Abstract
White mold WM caused by Sclerotinia sclerotiorum Lib de Bary is a widespread disease of dry and green bean Phaseolus vulgaris L in North America Gamete selection GS was effective to combine and pyramide resistant genes and quantitative trait loci QTL for common bacterial blight Our objective was to determine the effectiveness of GS to introgress physiological resistance to white mold Two intergenepool doublecross populations were developed Selection for WM resistance was practiced from F1 to F4 Thirteen selected F15 breeding lines of each population and their four parents were evaluated Two separate inoculations were made on each plant 1 week apart using a cutstem method The WM reaction was scored at 16 23 and 33 days post inoculation DPI using a scale from 1 no disease to 9 severely diseased or dead In F1 52 of Pop I USPTWM1/CORN 601//USPTCBB1/92BG7 and 67 of Pop II Chase/I936525//ABL 15/A 195 susceptible plants were discarded In F4 only 12 of families from Pop I and 09 for Pop II survived the selection process An average of 205 gain in WM resistance was obtained for both populations in F4 Four breeding lines of Pop I had significantly P = 005 lower WM score 41–46 and four were equal 47–49 to the best WMresistant parent 92BG7 49 while ten breeding lines of Pop II were equal 45–48 to the best WMresistant parent A 195 46 Thus GS was effective for improving WM resistance in common beanThis research was supported by the USDAARS National Sclerotinia Initiative Grant No 5854422256 “Introgressing White Mold Resistance from the Secondary Gene Pool of Common Bean” from 2002 to 2008 The authors also thank Drs P Miklas K Mohan H Schwartz R Zemetra and D Webster for careful review and comments on the manuscript and to R Hayes and his crew for their collaboration in the management of the greenhouses at the University of Idaho Kimberly Research and Extension Center Kimberly Idaho
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