GENOTYPIC DIFFERENCES IN YIELD AND QUALITY OF GROUNDNUT AS AFFECTED BY POTASSIUM NUTRITION UNDER ERRATIC RAINFALL CONDITIONS

ABSTRACT

A field experiment was conducted in completely rainfed conditions to determine the effect of different potassium (K) levels on yield and quality of two groundnut genotypes, namely GAUG-1 (bunch type or Virginia upright type) and GAUG-10 (spreading type or Virginia runner type) at Junagadh (Saurashtra region of Gujarat state, India) with highly calcareous vertic ustocherpt soil and erratic rainfall conditions. The two genotypes exhibited different response to varying levels of basally applied K (0, 25, 50, and 75 kg K₂O ha⁻¹). GAUG-1 responded the best to 25 kg K₂O ha⁻¹, while GAUG-10 to 50 kg K₂O ha⁻¹. Application of 25 and 50 kg K₂O ha⁻¹ increased the pod yield by 31% and 35% in GAUG-1 and GAUG-10, respectively. At maximum water deficit (soil moisture tension – 16.5 bars), during early growth stage (30 DAS), K application increased the stomatal resistance, proline content and leaf-K content and, thereby, decreased the transpiration rate, resulting in enhanced level of RWC, NRA, and chlorophyll content of leaf in both the genotypes. Thus, potassium application helped in achieving a better crop survival with improved yield and quality of groundnut under water deficit caused by erratic rainfall conditions.

ACKNOWLEDGMENTS

The facilities provided by the National Research Centre for Groundnut (NRCG), Junagadh, Gujarat, India and the financial support provided by Potash Research Institute of India, Gurgaon, India are gratefully acknowledged. Authors thank Drs. (Prof.) Mohammad Iqbal, R.S. Dwivedi, and P.C. Nautiyal for their useful suggestions and comments during preparation of the manuscript.