Recurrent selection for physiological resistance to white mould in dry bean

• Published in: Plant breeding Vol. 129; no. 3; pp. 327 - 333
• Main Authors: Terán, H, Singh, S.P
• Format: Journal Article
• Language: English
• Published: Oxford, UK Oxford, UK : Blackwell Publishing Ltd 01.06.2010; Blackwell Publishing Ltd; Blackwell
• Subjects: Agronomy. Soil science and plant productions; Biological and medical sciences; breeding methods; Breeding schemes. Varia; common bean; Fundamental and applied biological sciences. Psychology; Genetics and breeding of economic plants; Phaseolus vulgaris; Phaseolus vulgaris L; Plant breeding: fundamental aspects and methodology; recurrent selection; Sclerotinia sclerotiorum; Varietal selection. Specialized plant breeding, plant breeding aims; white mould resistance; Ascomycota; breeding methods; common bean; Plant pathogen; white mould resistance; Sclerotinia sclerotiorum; Phaseolus vulgaris L; Bean; Fungi; Resistance; Grain legume; Leguminosae; Vegetable crop; Phaseolus vulgaris; Dicotyledones; Recurrent selection; Angiospermae; Genetic improvement; Spermatophyta; Physiology
• ISSN: 0179-9541; 1439-0523
• DOI: 10.1111/j.1439-0523.2009.01679.x

With 1 figure and 5 tables White mould (WM) [caused by Sclerotinia sclerotiorum (Lib.) de Bary] is a widespread disease of dry and green bean (Phaseolus vulgaris L.) in North America and elsewhere. Our objective was to determine the effectiveness of recurrent selection (RS) for pyramiding WM resistance from Andean, Middle American and inter-specific breeding lines. Two double-cross populations, Pop I = USPT-WM-1/CORNELL 601//USPT-CBB-1/92BG-7 and Pop II = 'Chase'/I 9365-25//ABL 15/A 195 were developed. Each double-cross comprised 848 F₁ plants for RS cycle one (C₁). Twenty six WM-resistant plants from each double-cross were used to produce RS cycle two (C₂). To measure the gain for WM resistance, 13 selected S₂ families from each of C₁ and C₂ of each population and their four parents (C₀) were tested in a randomized complete block design with three replicates in two greenhouse environments in 2008. Two separate inoculations on each plant one week apart using a cut-stem method were made. The WM reaction was scored at 16, 23 and 33 days post inoculation (DPI) using a 1 (no disease symptoms) to 9 (severely diseased or dead plants) scale. The effects of environment were significant (P = 0.05), but replicate and population effects were not significant (P > 0.05). The RS was effective in changing the mean WM score of selected families from C₀ to C₁ and C₂, but the gain between C₁ and C₂ was not significant in Pop I. The gain in WM resistance for Pop I was 12%. Selection gain in Pop II was 5%, but no significant differences in mean WM scores of C₀, C₁ and C₂ were found. However, selected S₂ families had WM scores similar to those of the best parent and selected families from Pop I. Thus, one cycle of RS applied to double-cross populations was adequate for improving WM resistance in common bean.