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

Abstract

Fusarium root rot (Fusarium cuneirostrum) and Fusarium wilt (F. oxysporum) are major constraints on common bean (Phaseolus vulgaris L.) production worldwide as 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 Fusarium root rot and Fusarium wilt and recorded disease severity; resistance was observed in 21 and 16 accessions, respectively. PI 417775 was the most resistant accession to Fusarium root rot, exhibiting very few symptoms whereas accessions PI661845 and PI535441 were the most resistant to Fusarium wilt. Only accessions MX-GT-1 and PI535445 were resistant to both Fusarium root rot and Fusarium wilt.

Genetic variation in a tepary bean (Phaseolus acutifolius A. Gray) diversity panel reveals loci associated with biotic stress resistance

“…A previous, controlled evaluation identified several additional cultivated tepary beans as moderately resistant in the small set evaluated, Neb‐T‐5‐s and PI 321637‐s (G40022) (Miklas et al., 1998). Recent evaluations of wild common beans have identified 16 Fusarium wilt resistant accessions out of 248 evaluated (Haus et al., 2021). Future tepary bean trials would benefit from controlled environment evaluations of wild accessions where higher levels of resistance are likely to be found.…”

An image‐based technique for automated root disease severity assessment using PlantCV

“…Seven days post-inoculation, plants were harvested and roots were scored for disease severity as described previously by two trained researchers (van Schoonhoven and Pastor-Corrales, 1987;Wang et al, 2018;Haus et al, 2020Haus et al, , 2021. The roots were scored on a scale from 1-9, where "1" indicates no disease symptoms or discoloration and "9" indicates severe discoloration and extreme necrosis.…”

“…When evaluating disease severity caused by root rot pathogens, the roots are removed from the growth medium and visually assessed for disease symptoms. Most disease scoring systems use abbreviated semi‐quantitative scales, including those in common bean (Wang et al, 2018 ; Oladzad et al, 2019 ; Haus et al, 2021 ; Osorno et al, 2021 ; Sandoya et al, 2021 ). Because this scoring method is semi‐quantitative and root systems are scored based on visual estimates, it fails to capture the broad variation in these studies.…”

Mining legume germplasm for genetic gains: An Indian perspective

“…A set of 248 accessions of wild bean ( Phaseolus spp.) were screened under greenhouse, pot, and artificial conditions against fusarium root rot ( Fusarium cuneirostrum ) and fusarium wilt ( Fusarium oxysporum ), resulting in the identification of 21 and 16 lines resistant to fusarium root rot and fusarium wilt, respectively ( Haus et al, 2021 ). Urrea and Harveson (2014) carried out screening of 467 germplasm lines against bacterial wilt ( Curtobacterium flaccumfaciens pv.…”