Resistance to Iron Stress of Some Rice Genotypes in Calcareous Soil under Aerobic Condition

A field experiment was conducted in the research farm of Dr. Rajendra Prasad Central Agricultural University, Pusa, Bihar during the Kharif season of 2013 in iron-deficient highly calcareous sandy loam soil to screen the existing popular rice genotypes for their resistance against iron stress. Lime-induced iron chlorosis in rice is very common in upland calcareous soil. The genotypes responded differently to Fe application with respect to grain and straw yield as well as iron uptake by them. The average grain yield at soil application of 20 kg Fe ha-1 and 20 kg Fe ha-1 + two foliar sprays at pre-flowering and flowering stages of iron were statistically at par. Hence, 20 kg Fe ha-1 soil application may be considered was rated as an optimum level for most of the genotypes. From percent response (figure in parenthesis) of iron application to rice grain yield, the relative susceptibility of genotypes to iron stress may be arranged as Jirabati(37.9) >Prabhat(20.0) >R. Suwasshani(17.9) > Sanwal Basmati(11.5) > Vandana (10.2) > RAUAER-3(6.1) > MTU 7029(4.9) > RAUAER-5(4.4) > RAUAER-4(1.7). The percent response (figure in parenthesis) of iron application to iron uptake by grain, different genotypes may be arranged as R. Suwasshani(91.1) > Jirabati(86.5) >Prabhat(67.3) > RAUAER-3(19.6) > Sanwal Basmati(18.8) > Vandana (17.9) > MTU 7029(12.5)>Swarna Sub-1(11.7)>RAUAER-5(8.9) > RAUAER-4(6.3) . On the basis of iron efficiency (figure in parenthesis) the relative tolerance of rice genotypes to Fe stress may be arranged as RAUAER-4(94.2) > RAUAER-5(91.9) > RAUAER-3(85.6) > Vandana (91.9) > Sanwal Basmati (84.2) >MTU 7029(83.3) > Swarna Sub-1(83.1) >Prabhat(60.6) > Jirabati(55.4) > R. Suwasshani(52.7). The RAUAER-4 was the most efficient genotype followed by RAUAER-5 to tolerate iron stress soil condition.