| Asparagus plantings over many harvest seasons suffer declining yields and profit loss due to water stress, disease pressure, or combinations thereof. It was hypothesized that plant growth promoting rhizobacteria (PGPR) inoculation would improve asparagus growth and reduce the negative effects of water stress and disease caused by Fusarium oxyxporum f.sp. asparagi (Foa). Both field and greenhouse experiments were used to evaluate the effectiveness of single or repeated inoculations of two asparagus cultivars (Guelph Millennium (GM) and Jersey Giant (JG)) with two PGPR strains (Pseudomonas putida UW3 and P. putida UW4) on improving growth of water- or Foa-disease-stressed asparagus crowns and seeds. In the field, PGPR inoculation had no significant effect on plant growth. In the greenhouse, PGPR inoculation did increase growth, most prominently in the Guelph Millennium (GM) cultivar with multiple inoculations of P. putida UW3. Single UW3 inoculations also improved GM's resistance to Foa under optimum soil moisture and JG's resistance to Foa under flooding conditions. |
