Response of Rice Genotypes to Boron Fertilization and Screening of Efficient Rice Varieties under Boron Stress in Inceptisol

A pot culture experiment was conducted on Karaikal soil series (Vertic Ustropept) to study the response of rice genotypes to boron addition and screening efficient genotypes using stress indices. Ten rice genotypes were tested at two (0, 2 mg kg-1) level of boron. The result revealed that the highest grain yield (88.40 g pot-1) and straw yield (114.7 g pot-1), and the maximum grain boron uptake (2192.3 µg pot-1) and straw boron uptake (3291.9 µg pot-1) were recorded with application 2.0 mg boron kg-1. Amongst rice genotypes, ADT 50 recorded significantly the highest grain and straw yield, boron uptake and boron use efficiency compared to other genotypes on application of boron @ 2 mg kg-1. From the study results, we observed that there are significant differences among rice genotypes on yield, boron uptake and use efficiency with boron fertilization compared to no boron application. Further, based on stress tolerance index (STI), yield under stress (Ys) and adequate condition (Yp) rice genotypes were categorized into Group A – uniform superiority under stress and non – stress condition – ADT 50, ADT43 and ADT 53 with high STI > 1.0; Group B - perform favorably only under non – stress condition - ADT 46, ADT 52,ADT 51, ADT 40 and ADT 37 – STI - 0.7 to 1.0; Group C – genotype yield relatively higher only under stress environment – no genotypes ; Group D – genotype perform poorly in both stress and non-stress environment – ADT 38 and ADT 39 with low STI < 0.70.