Preliminary evaluation of wild bean (Phaseolus spp.) germplasm for resistance to Fusarium cuneirostrum and Fusarium oxysporum

Fusarium root rot (Fusarium cuneirostrum; FRR) and Fusarium wilt (Fusarium oxysporum; FW) are major constraints on common bean (Phaseolus vulgaris L.) production worldwide because limited genetic resistance is available in current cultivars. Wild accessions have greater genetic diversity than cultivated germplasm and could provide novel sources of resistance for these diseases. We screened 248 wild bean accessions in a greenhouse setting for responses to both FRR and FW and recorded disease severity; resistance was observed in 21 and 16 accessions, respectively. Accession PI417775 was the most resistant to FRR, exhibiting very few symptoms, whereas accessions PI661845 and PI535441 were the most resistant to FW. Only accessions MX‐GT‐1 and PI535445 were resistant to both FRR and FW. Overall, accessions collected from Andean regions had greater disease symptoms (5.4 ± 1.28 for FRR; 5.8 ± 1.12 for FW) than accessions collected from Middle America (4.7 ± 1.33 for FRR; 4.42 ± 1.04 for FW), though the highest and lowest disease scores for FRR were both found in the Middle American accessions. Introgression of Fusarium resistance from wild bean accessions into cultivated lines provides an avenue to improve disease resistance in elite cultivars. Core Ideas Domesticated dry beans have little genetic resistance to Fusarium root rot and Fusarium wilt. PI417775 was the most resistant accession to Fusarium root rot. PI661845 and PI535441 were the most resistant to Fusarium wilt. Wild beans collected in Andean regions had less average resistance than from Middle America. Larger seed size correlates to resistance within genepools, especially in Middle American lines.