A fungal endophyte consortium counterbalances the negative effects of reduced nitrogen input on the yield of field-grown spring barley

Abstract

SUMMARYThe use of chemicals to fertilize crops incurs economic and environmental costs and it is widely recognized that the current level of chemical fertilizer use is unsustainable in many intensive farming systems. Any methods that can reduce fertilizer input and still maintain acceptable yields would be of great benefit to both the farmer and the environment. The use of beneficial endophytes as crop inoculants may go some way towards improving crop yields beyond that achievable using fertilizer increases alone. Field trials were conducted over two seasons on three contrasting field sites to test the effects of fungal endophytes from a wild barley relative on three barley cultivars (Mickle, Planet and Propino). Seeds were either untreated or dressed with a consortium of four endophyte strains, and three levels of nitrogen (N) were applied to both treatments: full N, 50% N and 0 N. On the field site with the lowest overall N input, the endophyte treatment with 50% N restored yield for ‘Planet’ to that associated with untreated plants receiving the full N input. On the same site and with the same cultivar, endophyte treatment increased yield by 15% under full N, and by a mean 12% for all three cultivars with 50% N input. Over both seasons and all three sites, the endophyte treatment increased yield for the cultivar Planet by a mean of 9%. For the endophyte-associated increase in the variety Planet grain yield over the untreated trials strong correlations were found between increased yield and each of low rainfall, greater evaporation and greater number of degree days above the base. Furthermore, the efficacy of the endophytes was not removed by regular foliar fungicidal treatment. These results suggest that fungal endophytes can contribute to improving barley yield grown in low rainfall areas and under a range of fertilizer input regimes, provided that endophyte treatments are applied to compatible crop cultivars and sites.

Multistrain versus single-strain plant growth promoting microbial inoculants - The compatibility issue

“…A mixture of endophytic fungi isolated from wild barley eff ectively suppressed the seed-borne infections in a barley cultivar (Murphy et al, 2015). A fungal endophyte consortium consistently improved barley grain yield over several seasons under a variety of chemical fertilizer inputs and low seasonal rainfall (Murphy et al, 2017). Intra-or interspecies fungal consortia consisting of Clonostachys, Beauveria, Metarhizium or Trichoderma spp.…”

A Symbiotic Approach to Generating Stress Tolerant Crops

“…There are numerous reports describing the benefits of fungal endophytes on seed germination, seedling vigor, abiotic, and biotic stress tolerance, and increased biomass of crop plants [ 38 , 40 , 41 , 42 , 43 , 44 , 45 ]. Although there are comparatively few reports on endophytes improving crop production under field conditions [ 38 ], fungal endophytes have shown good field efficacy for enhancing yields, biological control, and improving yield quality [ 38 , 43 , 44 , 45 ]. Extensive field testing demonstrated that ThSM3a conferred tolerance to drought and temperature extremes in both a monocot (corn) and eudicot (cotton).…”

From Concept to Commerce: Developing a Successful Fungal Endophyte Inoculant for Agricultural Crops

“…The approach we have adopted in developing a crop inoculant, as outlined in this paper, has resulted in the successful translation of promising laboratory-based research to agriculture. In field trials with barley, we found that for an endophyte-associated increase in grain yield, a strong correlation was found between increased yield and low seasonal rainfall [ 31 ]. Furthermore, the endophytes were just as effective with regular foliar fungicidal treatment.…”

“…The approach adopted by our research group has consciously focused on making this transition from ‘pot to plot’ more successful. We aimed to remove the inconsistency from endophyte application in field crops by targeting a single crop, barley, as our model plant, and testing the efficacy of endophyte strains under various environmental stresses, culminating in extensive field trials [ 30 , 31 , 32 , 33 , 34 , 35 ]. Only with this field validation can we say with any confidence that a microbial inoculant really “works” [ 36 ].…”

“…Only with this field validation can we say with any confidence that a microbial inoculant really “works” [ 36 ]. We have demonstrated the effectiveness of this approach by developing a fungal endophyte inoculum that consistently increases barley grain yield over several seasons under a variety of chemical fertilizer inputs in dry growing environments [ 31 ]. The outcomes from our research and field application have been so successful that we have been able to bring our endophyte technology into commerce, which will result in significant reductions in economic and environmental costs.…”