Browsing by Author "Adarsh S"

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    Enhancing nutrient use efficiency in lowland rice using beneficial root endophytic fungus Piriformnospora indica
    (Department of Agronomy, College of Agriculture, Vellayani, 2025-12-30) Adarsh S; Ameena M
    The study entitled ‘Enhancing nutrient use efficiency in lowland rice using beneficial root endophytic fungus Piriformospora indica’ was conducted at the Department of Agronomy, College of Agriculture, Vellayani during 2019-2025. The objectives of the study were to standardise a suitable growing medium for the colonisation of P. indica in rice seedlings and to evaluate the performance of P. indica colonised rice under varying NPK levels in both pot and field conditions. The investigation comprised three experiments, each conducted using the rice variety Uma. The first experiment on ‘Standardisation of growth media for P. indica colonisation of rice seedlings’ was conducted as a lab study at the Department of Plant Pathology to standardise a growing medium for colonisation of P. indica in rice. The experiment was laid out in completely randomized design with eight treatments replicated nine times. The treatments were: T1 [Paddy soil (PS): FYM: vermicompost (VC) in 1:1:1 (v/v) with P. indica (+Pi)], T2 [PS: FYM:VC in 1:1:1 without Pi (-Pi)], T3 [PS: FYM: neem cake(NC)in 1:1:1 + Pi], T4 [PS: FYM:NC in 1:1:1 - Pi], T5 [PS: FYM: coir pith compost (CPC) in 1:1:1 + Pi], T6 [PS: FYM: CPC in 1:1:1 - Pi], T7 [PS: FYM:VC:NC: PC in 1:1:1:1:1 + Pi] and T8 [PS:FYM:VC:NC:CPC in 1:1:1:1:1-Pi]. The sterilized medium prepared as specified, was inoculated with fungal broth (10 g mycelia per 100 g medium), and sown with surface-sterilized seeds to assess the growth and colonization. Results revealed that, T5 resulted in the highest germination percentage (92.28), dry matter production (19.12 mg per plant), vigour index-1 (1953.67), root volume (0.15 cm³ per plant), root dry weight (10.29 mg per plant), and root colonisation efficiency (92.70 %) at 14 days after sowing. Based on the growth and colonisation potential, the substrate comprising equal proportions of PS, FYM, and CPC was identified as the promising for mass colonisation of P. indica in rice seedlings. The second experiment on ‘Response of P. indica colonised rice to various NPK levels’ (pot culture) was laid out in CRD (factorial) with five nutrient levels and two types of colonization (2) replicated thrice (10 treatment combinations) with seven pots per replication. The treatments comprised of T1 [100% NPK + Pi], T2 [75% NPK+Pi], T3 [50% NPK+Pi], T4 [25% NPK+Pi], T5: [0% NPK+Pi], T6 [100% NPK–Pi], T7 [75% NPK–Pi], T8 [50% NPK–Pi], T9 [25% NPK–Pi], and T10 [0% NPK-Pi (Absolute control]. Rice was raised as per KAU POP recommendations. Colonisation at 100% NPK resulted in the tallest plants and the highest dry matter production at harvest (37.79 g per plant). However, the number of productive tillers per plant under 100% NPK + Pi was comparable to T2, which in turn was on par with 100% NPK - Pi for productive tillers, grain yield, and straw yield per plant. 100% NPK + Pi showed superior values for major root parameters. However, 75% NPK+ Pi were statistically on par with non-colonised plants at 100% NPK for root length, root volume, number of root branches, and root-shoot ratio. Colonisation and nutrient levels had significant influence on physiological parameters of rice. Malondialdehyde (MDA) content was lower in colonized plants at 100 % NPK. However, the highest superoxide dismutase (SOD) and peroxidase were recorded in 75% NPK+ Pi and on par with 100% NPK. The soil chemical analysis revealed the significant influence of colonisation with 100% NPK + Pi recording higher available N and P and plant P uptake which were comparable to 75% NPK + Pi. The three promising nutrient levels of pot experiment viz., 100,75 and 50% NPK with and without the endophyte along with absolute controls were taken for the field experiment. The third experiment on ‘Evaluating the field performance of P. indica colonised rice to various nutrient levels’ was laid out in RBD (factorial) with four nutrient levels and two types of colonization replicated thrice. The treatment combinations were T1 [100% NPK+Pi], T2 [75% NPK+ Pi], T3 [50% NPK+Pi], T4 [0% NPK+Pi], T5 [100% NPK–Pi], T6 [75% NPK–Pi], T7 [50% NPK–Pi], and T8 [0% NPK-Pi]. The crop of rice was raised as per KAU POP recommendations. Among the yield parameters, 100% NPK +Pi resulted in the highest yield attributes. However, performance of 75% NPK +Pi was comparable to KAU POP with respect to yield attributes at both locations. A pooled grain yield of 6.24 t ha⁻¹ was obtained with 100% NPK + Pi followed by 75% NPK + Pi (5.27 t ha⁻¹). Regarding root parameters, root length (37.90 cm) and root dry weight (10.05 g) were superior in colonised plants at 100% NPK followed by 75% NPK+Pi at 45 DAT. Colonisation and nutrient levels had their significance on physiological parameters. The nutrient use efficiency parameters of rice were significantly influenced and Pi + 100% NPK resulted in superior agronomic efficiency (AE) of N, P and K; apparent recovery efficiency (ARE) of N and K; physiological efficiency (PE) of N and K; and partial factor productivity (PFP) of N and P for both locations. Economic analysis revealed that the net income and benefit cost ratio were the highest in 100% NPK +Pi for both locations whereas 75% NPK +Pi was profitable than 100% NPK -Pi in both locations. The study identified a growth medium comprising equal proportions of paddy soil, farmyard manure, and coir pith compost as the most effective one for colonising P. indica in rice, based on growth and colonisation efficiency. Field evaluation of seedlings raised in this medium, supplied with NPK as per KAU POP recommendations, showed the highest overall performance in terms of growth and yield. However, the yield of colonized plants receiving 75 per cent of the recommended NPK was on par with non-colonised plants receiving full NPK. Based on the above findings, it could be inferred that P. indica colonization can facilitate 25 per cent reduction in chemical fertilizer use without compromising the productivity of transplanted lowland rice during summer.