Screening Diverse Rice (Oryza sativa L) Genotypes for Manganese Efficiency

Soil manganese (Mn) deficiency limits the growth and crop yield. Growing Mn efficient cultivars i.e. the cultivars with high yield at low Mn supply would represent a long term solution and sustainable approach to crop production. To evaluate Mn efficiency of 38 diverse rice geno-types, field experiment was conducted during kharif seasons using Mn deficient (2.20 mg kg(-1)) soil. Typic Ustrochrepts loamy sand soil, treated with 0 kg Mn ha(-1) (no Mn, low level) and 20 kg Mn ha(-1) supplemented with two foliar sprays @ 0.5 % MnSO4 (high level). The relative grain yield i.e. Mn efficiency index varied from 100 to 84 % and relative grain Mn uptake i.e. Mn efficiency from 80 to 53 % among the genotypes and the cultivar PR116 was having highest Mn efficiency index as well as efficiency. On the basis of grain yield and Mn efficiency, genotypes were classified as efficient and responsive (PR116, 3047, PAU201, 3131, 3125, HKR127, 3106, 3129, 3128, 3100 and 3138), efficient and nonresponsive (PR120, PR113, 3126, 3033, 3132, 3056, 3130, 3036, 3109, 3124, 3101 and 3136), inefficient and responsive (3127, PR115, 3133, 3134 and 3142), and inefficient and nonresponsive (PR114, PR118, 3137, PR111, 3108, PUSA44, 3135, 3139, 3140 and 3141). From a practical point of view, genotypes that produce high grain yield at a low level of Mn and respond well to Mn additions are the most desirable because they are able to express their high yield potential in a wide range of Mn availability.