Beneficial Effects of Microbial Inoculation to Improve Organic Potato Production under Irrigated and Non-Irrigated Conditions

Summary

Many microorganisms such as arbuscular mycorrhizal fungi (AMF), plant growth promoting rhizobacteria (PGPR) and Trichoderma spp. can form a symbiotic association with host plants, which can have a significant impact on plant growth and yield. In two years experiment, we investigated the possible role of seven different treatments of microbial inoculates to improve the potato tubers production and quality under irrigated and non-irrigated conditions. Potato cultivar "Desiree" was used with seven treatments of mixture of microbial inoculates including AMF, PGPR and Trichoderma spp. in 64 experimental parcels. The results indicated that the mycorrhizal colonization intensity and mycorrhizal frequency were increased in non-irrigated treated and the control plants over the two years. Most of the treatments did not show arbuscular abundance in both the years except the mixture of Rhizophagus irregularis MucL41833+Pseudomonas brassicacearum (41%), R. irregularis MucL41833+ Paraburkholderia phytofirmans (24%) and Trichoderma asperelloides A (33%). Starch content was similar between different treatments in both the years, without significant differences with control plants. In 2020, the highest starch value was found in P. phytofirmans PSJN treatment with (17.16%) mean under irrigated and non-irrigated conditions. In 2021, the highest starch value among the irrigated parcels was found in R. irregularis MucL41833 treatment (12.29%). In terms of total phosphorus content, the control treatment in the second year (2021) gave the highest total phosphorus content in the irrigated conditions (0.69 mg kg-1) followed by the mixture treatment of the microbial inoculates treated plants R. irregularis MucL41833 and P. phytofirmans (0.68 mg P kg-1). For the tubers yield, the treated plants under irrigated conditions gave the highest mean. In the first year, P. phytofirmans PSJN gave the highest yield (15.21 kg/m2) under irrigation conditions, while in the second year, R. irregularis MucL41833 showed the highest yield (16.72 kg/m2) in the irrigated conditions as well, followed by the control treatment in both the years. Our findings could be a practical addition to further researches on the effects of microbial inoculates on organic potato production in field conditions, understanding the different interactions and effects of the applied microbial inoculates, which may differ according to the environmental conditions and the host plants.