Multiple Bacterial Disease Resistance of Common Bean (Phaseolus vulgaris L.) Lines

Abstract

Breeding and the use of resistant cultivars is the most efficient means for relatively long-lasting control of the diseases on common bean; the introduction of cultivars with multiple disease resistance in production is preferable to the use of cultivars which are resistant to one disease only. The aim of this investigation was to determine the response of 50 dry bean lines to P. s. pv. phaseolicola (Psp), X. a. pv. phaseoli (Xap) and C. f. pv. flaccumfaciens (Cff) with a view of selecting lines with multiple resistance to the three bacterial diseases. The reaction of the lines to Psp и Xap was read under field conditions, and to Cff – under field and greenhouse conditions. The inoculation of the leaves with isolates of Psp races 1 and 6 and with two Xap isolates was done by the multiple needle method and the inoculation of pods – with a single syringe. The inoculation of the plants with Cff was done with a syringe at stage primary leaves. The response of the lines was recorded 14 days after inoculation for Psp and Xap, and after 28 days – for Cff. Five of the investigated lines (DG 6-24-1, DG 6-24-2, DG 6-24-3, DG 6-24-5 and DG 6-26-2-5) possessed resistance to races 1 and 6 of Psp, to isolates ХВ96221 and ХВ99132 of Xap and to isolate СС 96201 of Cff. Lines DG 6-26-2-3, DG 6-26-2-6 and DG 6-26-3-16 were resistant to Psp and Cff and possessed a resistant phenotype of leaves to Xap, but the resistance of the pods to the latter bacterial disease was moderately susceptible. The above lines have erect habit type (type ІІa) suitable for direct harvesting, absolute 1000 seed weight within the range 297 – 406 g, raw protein content within 17.5 – 22.6% and high resistance to linuron. Their multiple bacterial disease resistance and valuable economic properties allow using them as donors of resistance and/or including them in the Varietal List of Bulgaria.