Physiological Studies on Heat Stress Tolerance in Groundnut (Arachis hypogaea L.) Genotypes
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Date
2017-06
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University of Agricultural Science, Dharwad
Abstract
A field experiment was conducted at MARS, University of Agricultural Sciences, Dharwad during kharif, 2016-17. The experiment consisted of three temperature regimes (dates of sowing D1, D2 and D3) and five groundnut genotypes (Dh-86, G-2-52, Kadiri-9, TMV-2 and R-2001-2) laid out with factorial RBD design. The experimental result reveals that D1 temperature regime recorded significantly higher plant height (41.01 cm), number of primary branches (7.14), days to 50% flowering (35.73), days to peg initiation (40.20) and days to physiological maturity (109.73) with more heat unit accumulation, pheno thermal index and heat use efficiency.
Highest pollen sterility (12.73 %) and reduced total flower production (59.11) was noticed under D3 temperature regime. The genotypes, G-2-52 and R-2001-2 were recorded significantly less pollen sterility (8.442 %) and more number of flower productions (100.74), respectively. However, significantly higher number of pods (17.69) and lower flower to pod ratio (3.989) was observed under D1 temperature regime. Among the genotypes, G-2-52 recorded significantly higher number of pods (16.67) and lower flower to pod ratio (4.706), respectively.
Yield and yield components viz., number of pods plant-1 (17.69), test weight (35.78 g), harvest index (31.78 %), oil content (44.26 %) and yield (4952 kg ha-1) were remarkably higher under D1 temperature regime. Among the genotypes, G2-52 performed better irrespective of all temperature regimes with optimum yield (3,074 kg ha-1) compared to other genotypes indicating its relative tolerance to heat stress.