Effects Of Two Plant Growth Promoting Rhizobacteria On Agronomic Traits And Nutritional Quality Of Potato

The role of Plant Growth Promoting Rhizobacteria(PGPR)in promoting plant growth and development,maintaining plant health,improving plant productivity,and improving fruit quality is gradually being revealed and recognized.In addition,bacteria have fast reproduction speed,are easy to achieve high-density and low-cost fermentation,and have high application value.Therefore,plant rhizosphere bacteria have become a research frontier and hotspot.In the early stage of our laboratory,two rhizosphere promoting bacteria,Kocuria rosea SDB9 and Brevibacterium frigoritolerans SDB5,were isolated from Sabina vulgaris.The preliminary experimental results showed that the above strains had good effects on promoting plant growth and increasing yield.However,the impact of these strains on potato agronomic traits and nutritional quality has not been systematically studied.This study used a seed soaking method to inoculate potato slices and whole potatoes,and investigated the effects of single or combined use of two types of bacteria on the agronomic traits and nutritional quality of different potato varieties.The results indicate that:(1)Different bacterial treatments have varying degrees of impact on the morphology of potato plants.Different bacterial treatments,varieties,and cultivation years result in significant changes in potato plant height,stem diameter,and number of main stems.Overall,the response effect of Qingshu 9 to bacterial treatment is more significant than Kexin 1,which is speculated to be related to its own plant morphology and larger aboveground biomass;(2)Different bacterial agents have a significant impact on the yield components of potatoes.Among them,the SDB5 treatment had the most obvious effect on the yield of commercial potatoes under the condition of cutting and soaking seeds.The yield of commercial potatoes increased by 33.46% compared to CK,and the SDB95 treatment had the most obvious effect on the number of tubers per plant,which could increase by10.55%;The results of whole potato soaking and cultivation in different years indicate that different bacterial treatments can significantly improve the yield of commercial potatoes.There are significant differences in the weight and number of tubers per plant between different treatments,which is speculated to be related to insufficient sample statistics and environmental changes;(3)Different bacterial treatments have a significant impact on potato yield.Under different inoculation methods and cultivation conditions in different years,different bacterial treatments can significantly increase potato yield,with an increase in yield ranging from 1.35% to 24.21%.The field effect of seed soaking inoculation by cutting is better than that of whole potato inoculation on the whole.It is speculated that it is related to the outflow of sugar and other nutrients from the cutting,which is conducive to the colonization and propagation of bacteria,and thus better play the priority effect when bacteria occupy the ecological niche;(4)Different bacterial treatments can reduce the occurrence of tuber scab.On the whole,different bacterial treatments reduced the incidence rate of scab under most cultivation conditions,and the incidence rate could be reduced as high as 35.10%,achieving a certain control effect.The control effect of whole potato seed soaking was better than that of cut seed soaking;(5)Different bacterial treatments have a significant impact on the quality of potatoes.Overall,SDB95 treatment has the best effect on improving dry matter content,with a maximum increase of 20.84%.SDB5 treatment has the best effect on improving vitamin and starch content,with a maximum increase of 63.50% and 60.17%,respectively.SDB95 treatment has the best effect on protein content,with a maximum increase of 49.30%.The reducing sugar content has a significant increase,with a maximum increase of 48.48%,under SDB5 or SDB9 treatment alone,which is not conducive to improving potato quality,The nitrate content decreased the most significantly with SDB95 treatment,with a maximum reduction of 25.55%,which is beneficial for improving potato quality.In summary,the results of the preliminary and formal experiments are basically consistent,and the inoculation effects of whole potatoes and cut potatoes are basically the same.This indicates that both functional bacteria can stably colonize different types of potato seed potatoes,and play their role in increasing yield and improving main nutritional quality.The results of this study clarify the effects of Kocuria rosea SDB9 and Brevibacterium frigoritolerans SDB5 on the agronomic traits and nutritional quality of potatoes,laying the foundation for the promotion and application of these two microbial agents in potato production,which will contribute to the green and highquality development of the potato industry in Yulin and the northwest region.