Background Chickpea is the most important legume crop in India, and its productivity is significantly lowered due to biotic constraints such as wilt caused by Fusarium oxysporum f. sp. ciceris. Endophytes help plants to thrive better under stress conditions by regulating plant hormones and inducing systemic resistance. The aim of the present study was to identify chickpea root bacterial endophytes having antagonistic ability for the management of the Fusarium wilt. Results Twenty endophytic bacterial strains were isolated from the susceptible and resistant chickpea cultivar, amongst which 35% bacterial endophytes gave positive results for siderophore and 15% isolates were HCN producers, whereas 55% showed good growth on ACC-supplemented medium. Based upon 16S rRNA phylogenetic analysis, efficient endophytic bacterial isolates CRBE1, CRBE3 and CRBE7 were identified as Priestia megaterium, Brucella haematophila and Microbacterium paraoxydans, respectively. Bacterial endophyte CRBE7 and CRBE3 showed pronounced antagonistic activity against Fusarium oxysporum f. sp. ciceris under in vitro conditions. Inoculation of chickpea with isolated bacterial endophytes alone and in combination through seed priming resulted in significant biocontrol activity against Fusarium wilt of chickpea under screenhouse conditions. Biopriming of chickpea seeds alone with CRBE3 and as consortium of CRBE3 + CRBE7 upsurged the phenol content in susceptible and resistant chickpea varieties JG 62 and HC 3, which indicated the role of promising endophytes as potential bio-agents under in vivo conditions. Conclusions Chickpea root bacterial endophytes Priestia megaterium (CRBE1), Brucella haematophila (CRBE3) and Microbacterium paraoxydans (CRBE7) exhibiting antagonistic activity could be incorporated in integrated disease management module against Fusarium wilt of chickpea.

Fusarium wilt incited by Fusarium oxysporum f. sp. ciceris causes substantial economic losses in chickpea. Tostudy the effect of mycorrhizal inoculation in combination with different bio-agents, fungicides and botanicals onthe Fusarium wilt incidence and yield of chickpea, field trials were conducted during 2019–20 at the research field ofCCS Haryana Agricultural University, Hisar. Mycorrhizal fungi were found to be beneficial in alleviating chickpeawilt incidence and upsurging the yield components of chickpea. The mycorrhizal fungus Glomus mosseae performed better than Glomus hoi, evincing the importance of mycorrhizal species. Seed soaking provided more disease control in comparison to soil drenching of plant extracts, bio-agents and fungicides except azoxystrobin 23% SC in variety JG 62 in which mode of application of fungicide had no significant effect on disease incidence. Amongst mycorrhiza × treatment interaction, carbendazim 50% WP provided utmost disease control (>80%) in the soil pre-inoculated with G. mosseae and Glomus hoi, followed by azoxystrobin 23% SC and Trichoderma viride, while aqueous extract of datura leaves was the least effective in both chickpea varieties JG 62 and C 235.

Fusarium wilt incited by Fusarium oxysporum f. sp. ciceris is an economically damaging disease of chickpea (Cicer arietinum L.). Field experiments on epidemiological studies revealed that sowing during second fortnight of November curtailed the disease severity index (22.50 and 20.83% during 2018-19 and 2019-20, respectively) whereas, sowing during first fortnight of October enhanced the disease severity index (34.86 and 30.41%). The area under disease progress curve was significantly higher in susceptible variety JG 62 and was the least in resistant variety HC 1. The correlation analysis exhibited positive correlation of disease severity index with maximum and minimum temperature while negative correlation with relative humidity morning and evening, irrespective of date of sowing. The principal component analysis depicted resistance index, sowing time and weather parameters as positional factors in determining Fusarium wilt progression.  In susceptible variety, Gompertz model was the best fitted model for simulating the Fusarium wilt epidemic over time.

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