Evaluation of Total Phenol Content of some Common Paddy Cultivars of Odisha with the Application of Biofertilizer in Assessing Resistance to Meloidogyne graminicola

The total phenol content of four common paddy cultivars of Odisha namely Abhisek (R), Manik (MR), Bas-12 (S) and Lalat (HS) were studied under pot culture condition in the net house following CRD design under different treatments using biofertilizer Azospirillum. brasilense alone or in combinations against rice root-knot nematode Meloidogyne graminicola. The objective of the work was to study the quantitative changes in phenolic compounds content and the effect of A.brasilense in the induction of phenolic compounds on the test nematode. It was observed that there was a significant increase in total phenol content in both resistant and moderately resistant paddy cultivars Abhisek and Manik in treatment T2 (Azospirillum brasilense @ 12kg/ha at 15DAT + M. graminicola @ 1000J2 after 7days of Azospirillum inoculation) were seen higher than the susceptible variety Bas-12 and highly susceptible variety Lalat as compared to control T5 with increase percentage of 38.77%, 36.58%, 35.02% and 39.28% respectively in shoots. Similarly the trend was continued in roots containing total phenol content of 0.25mg/g in Abhisek, 0.18mg/g in Manik, 0.21mg/g in Bas-12 and 0.19mg/g in Lalat as compared to other treatments. There were increase in percentage of change (p≤0.05) in roots under treatment T3 (A alone) in all the four varieties followed by T2 (A→N), and T1 (N→A) with respect to control T5. Basically, shoots of control plants in all four cultivars were observed more content of phenolic compounds than their roots. But after M. graminicola invasion and the action of A. brasilense the amount increased in both the roots and shoots of all the cultivars. The T4 (N alone) treatment in all the R, MR, S and HS varieties were recorded higher as compare to T5 but less than the treatments T3, T2, and T1 in both roots and shoots against the test nematode, which could exacerbating for eco-friendly RKN management approach.