Effect of different levels of potassium nutrition and foliar spray of kinetin on physiology yield and grain quality of rice cultivars in iron toxic soil

Abstract

Rice crop requires iron for growth, but excess iron beyond optimal levels can be newlineharmful. Lowland rice with a high concentration of readily reducible and active iron, newlineparticularly in humid regions of Asia, is commonly affected by iron toxicity, a widespread newlinenutritional disorder. Lowland rice output is thought to be reduced by iron toxicity by 12 100%, newlinedepending on the cultivars, severity of iron toxicity stress, and fertility of the soil. This edaphic newlinecondition leads to an imbalance of other nutrients, which makes rice poor in nutrients. A field newlineexperiment was conducted in the wet season of 2022 in the very acidic iron rich lowland soils newlineof central farm, Odisha University of Agriculture and Technology Bhubaneswar, using 32 highyielding newlinerice cultivars and four different potassium doses because potassium (K) is a possible newlinecation to lower Fe toxicity in a split plot design and replicated twice. The experiment was newlinerepeated in the same field with the selected 5 rice cultivars (Lalat, Manaswini, Hiranmayee, newlinePratikshya and Tejaswini) from the previous year in the wet season of 2023. The main plot newlineconsisted of the above five popular rice cultivars treated combinable with two foliar sprays of newline200 ppm kinetin (Kn) along with five doses of potassium nutrition (0, 40, 80, 100 and newline120 kg ha-1) and was replicated thrice. The purpose of the experiment was to identify the most newlinesuitable rice cultivars for examining the possible effects on different K fertilizer levels and newlineexogenous kinetin application in lowland rice in iron toxic soil, with the aim of improving rice newlinegrain quality and yield. The findings showed that grain yield was increased by sole use of K as newlinewell as combined application of K with Kn but the percent grain yield varied with in a range of newline49.40% to 83.11% and 66.51% to 112.70% respectively, implied that K alone was not newlinesufficient to alleviate iron exclusion and increase rice yield in low land iron toxic soil. Kinetin newlineapplication improved the sink capacity and thereby enhanced the photosynthates translocation newlineprop