Iron deficiency chlorosis (IDC) causes a significant reduction in yield of groundnut grown in calcareous and alkaline soils in India. The main aim of the study was to assess genotypic differences for morpho-physiological parameters associated with IDC resistance across different stages and their effect on yield and its related traits. The factorial pot experiment was comprised of two major factors, i) soil-Fe status [normal-Fe, deficit-Fe], and ii) genotypes [five] with differential IDC response, constituting 10 treatments. They were assessed for five morpho-physiological parameters associated with IDC resistance across five crop growth stages and also yield and its related traits. Associations between these traits were also estimated. Under deficit-Fe conditions, IDC resistant genotypes recorded significantly lower visual chlorosis rating (VCR), higher SPAD values, active Fe, chlorophyll content, peroxidase activity, and high yield compared to susceptible ones. Between normal-to deficit-Fe soils, resistant compared to susceptible genotypes showed no change in VCR scores; a lower reduction in SPAD, chlorophyll, active Fe, peroxidase activity, and pod yield. Under deficit-Fe conditions, high yield among resistant genotypes could be attributed to higher seed weight, number of pods and haulm yield, while contrasting reduction in main stem height and number of primaries. The results indicate that for initial large-scale screening of groundnut genotypes for IDC resistance, SPAD values are most ideal while active Fe could be utilized for confirmation of identified lines.

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Eight groundnut genotypes of including four released and pre-released genotypes were evaluated for moisture stress at pegging (M2) and pod development (M3) stage stress situations with control (M1) during post-rainy season (Nov-April), 2018-19 at University of Agricultural Sciences, Dharwad and Karnataka, India. The drought stress was imposed by with holding irrigation at 40-80 DAS (M2) and 80 DAS-harvest (M3). Observations were recorded for physiological parameters like leaf area, SPAD readings, chlorophyll content, stomatal frequency, photosynthetic rate and pod yield per plant. Among the selected genotypes, GPBD-4, Dh-257 and Dh-256 are considered as drought tolerant genotypes at both the stress levels based on lesser reduction in leaf area, optimum chlorophyll content and photosynthetic rate, less leaf folding and by these adaptations recorded reduced reduction in pod yield over control. Genotypes, Dh-86 and TMV-2 affected severely by drought at both the stages. But higher effect was observed under pod developmental stage stress.

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