Field screening of rice cultivars for growth, yield and nutrient uptake in acidic soil

Iron toxicity results in imbalance between the rate of supply and uptake of nutrients resulting in reduced crop growth and yield. The objective of the study was to screen the cultivars of rice (Oryza sativa L.) which are capable of tolerating such conditions as prevalent in marginal lands. Two year data of field evaluation in the acidic soil of Ponnampet (pH 4.5, Organic carbon 2.0), Karnataka, India revealed mild bronzing symptom exhibted by all the cultivars tested. The growth of IR 36 and Siyam Halus was severely affected while that of Intan Gouri, Damodar, Getu, and Siyam Kuning was moderately affected. Mahsuri, which proved to be fairly tolerant gave the highest yield followed by SHM and CSR 4. The tissue and grain analysis revealed that the sensitive cultivars accumulated higher iron content. Further, lower contents of P, K, Ca, and Mg in tissues and grains have contributed to the susceptibility of rice to iron toxicity. The nutrient ratios of N/Fe, P/Fe, Mn/Fe, and Mg/Fe in grain were higher in tolerant cultivars.