Thermochemical organic fertilizer for mass multiplication of Piriformospora indica and its potential for nutrient acquisition and translocation in tomato.

Abstract

A study entitled “Thermochemical organic fertilizer for mass multiplication of Piriformosporaindica and its potential for nutrient acquisition and translocation in tomato” was carried out at the Department of Soil Science and Agricultural Chemistry, College of Agriculture, Vellayani during 2021-2024. The objective was to study the effect of thermochemical organic fertilizer (TOF) for the mass multiplication of beneficial root endophytic fungus Piriformosporaindica and to evaluate its potential for the release, acquisition and translocation of nutrients in tomato. Root endophytic fungus P. indicacultured on PDA medium and maintained at Department of Plant Pathology, College of Agriculture, Vellayani (No. INBA3202001787) was used. TOF supplemented with jaggery, neem cake, gram flour and groundnut cake at two concentrations (0.25% and 0.5%) were inoculated with P. indica culture @ 50 ml kg-1 of TOF. TOF added with 0.25% gram flour showed highest log cfu (7.80 g-1 TOF) during 3 months of storage at 30℃. This was followed by TOF treatment with 0.25% neem cake (log cfu of 7.53 g-1 TOF). Highest cfu of P. indica was observed by storing at 30℃ followed by storage at 22℃ and least at 4℃. TOF+0.25% gram flour (TG) was selected as the best treatment; and added with tricalcium phosphate (TCP) and rock phosphate (RP) at the rate of 0.5, 1.0 and 2.0 per cent insoluble P2O5 per kg TOF to study the nutrient release pattern and mineralization of P and Ca by P. indica for a period of 120 days. Highest available P and Ca were obtained from the treatment of TG+0.5% RP after 60 days. Availability of P and Ca was increased to 27.51% and 34.84% respectively by P. indica than its control by 60 days. P. indicasolubilized more P from lesser per cent of RP and TCP, as it triggers P uptake in P deficient condition. After 60 days of inoculation, availability of P and Ca reduced further. Potting medium prepared in 1:1:1 (v/v/v) of TG: coir pith: soil, along with different NPK rates with and without P. indica were evaluated for the growth 269 performance of tomato. Tomato seeds in P. indica treated TOF media recorded highest germination percentage (94.60%), seedling vigour index (1362.79), shoot length (14.4 cm) and root length (16.1 cm). Potting medium supplemented with 75% N+ 50% P+100% K + P. indica resulted in an increase in available N (17.70%), P (13.28%), K (1.82%), Ca (6.05%), Mg (5.84%) and S (7.59%). The plants treated with 50%N+50%P+100%K+P. indicaincreased fruit yield (4.27%), fruit number (8.16%) followed by the treatment of 75% NPK with an increase of 3.93% and 7.71% in fruit yield and fruit number respectively. Computation of transfer and translocation factors implied that the treatment of potting medium with 75% N+ 50% P+100% K + P. indicahad the highest transfer factor of 0.81, translocation factor I of 2.69 and translocation factor II of 4.31. This indicates the highest nutrient uptake by above ground parts from the roots was influenced by P. indica. The best three treatments from the pot culture study were tested in the field along with inorganic fertilizer on soil test basis with and without P. indicaand KAU POP as control. Pooled analysis of nutrients in both rabi and summer season showed a higher nutrient status and yield parameters for the best treatment from pot culture study with fertilizers on soil test basis (63% N+ 12.5% P+37% K+ P. indica. Compared to the POP based recommendation, the above treatment increased soil available N (12.17%), P (24.37%), K (8.28%), Ca (14.12%), Mg (39.67%) and S (48.21%). It also recorded the highest plant height (74.38 cm), number of primary branches per plant (7.80), number of leaves (26.86), number of fruits (64.77), fruit yield per plant (1.61 kg/plant) and lowest days to first flowering (41.34 days). P. indica-colonized tomato plants exhibited better resistance than control plants in pest incidence and disease severity as they had higher antioxidant enzyme activities viz., peroxidase (61.09 µg min-1 g-1), superoxide dismutase (186.02 mg g-1) and catalase (311.71 µg min-1 g-1). The constituent organic acids and reducing sugars present in TOF enabled mass- multiplication of P. indica in TOF medium with 0.25% gram flour and thereby is an ideal carrier medium for P. indica. From the medium of TOF along with insoluble phosphatic sources such as tricalcium phosphate and rock phosphate at three 270 different rates of 0.5, 1.0 and 2.0 per cent, P. indica solubilized more P and Ca from 0.5 per cent rock phosphate. TOF inoculated with P. indicaenabled efficient root architecture and stimulated the nutrient uptakeby expressing nitrate (LeNRT2.3) and phosphate (LePT1) transporter genes; thereby triggering the transfer factor and translocation of nutrients from root to shoot and to fruit. This facilitated a reduction in external inorganic input requiring only 56 per cent of N and 30 per cent of P as compared to the soil test based NPK recommendation as per package of practices, KAU. The synergistic interaction of P indica in TOF based medium through its massmultiplication facilitated efficient root phenomics, nutrient release, acquisition, uptake and translocation with enhanced crop biometrics, yield and economic biomass production in tomato.