BENEFICIAL EFFECTS OF BACTERIAL ENDOPHYTES ISOLATED FROM POTATO ROOTS AND TUBERS ON NUTRIENT SOLUBILIZATION

Abstract

The application of agrochemicals to improve nutrient uptake in plants has several negative effects on soil health. The use of plant growth-promoting rhizobacteria (PGPR) with nutrient solubilizing properties has become an attractive alternative to the synthetic chemicals. Endophytic bacteria have the potential to be utilized effectively in integrated nutrient management for crops. Being a vegetatively propagated crop, potato is continuously perpetuating a large number of microorganisms in its tuber as well as in its roots. Bacteria from potato tubers and roots were isolated and tested for their ability to solubilize Zn, P, and K and to produce siderophores on zinc, pikovskaya, aleksandrow, and chromo azurol S medium, respectively by serial dilution plate technique. A pot experiment was also conducted to study the effect of isolated endophytes on potato plant growth and yield. Among all, isolate PSB2 was found the best withstanding
high pH and NaCl salt concentration. At seven days after inoculation (DAI) on respective media, it produced siderophore, IAA (9.79 g/ml), and solubilized phosphate (21.20 P g/ml). All six bacterial isolates showed a positive impact on growth and growth attributing characteristics in potato cv. Kufri Jyoti. Treatment T11 received recommended dose of nitrogen, phosphorus, and potassium (RD+NPK) + Zn in soil and a combination of endophytes isolates seed tuber treatment recorded
maximum germination percent, plant height, fresh and dry biomass, and tuber weight which was significantly superior over un-inoculated control and at par with 100 % recommended dose of fertilizers (T1) suggesting possible saving in 25% of chemical fertilizers viz. phosphatic, potassium and zinc requirement in potato cultivation.