Effect of Moisture Regimes on Water use Efficiency of Rabi / Summer Groundnut Genotypes in Northern Transition Zone of Karnataka

Abstract

Background: During rabi / summer irrigation water is a scarce resource, but crop needs more water due to non-rainy season and warmer climate. Hence, a field experiment was conducted during rabi / summer season of 2016-17 to study the effect of irrigation water regimes on water use efficiency (WUE) of groundnut genotypes in Northern Transition Zone of Karnataka. Methods: This field study comprised of four main plots as water regimes viz. I1: (control) seven irrigations at 15 days interval from sowing to 105 DAS, I2: Stress at pegging stage; withdrawal of one irrigation between 45 - 60 DAS, I3: Stress at pegging and pod filling stage; withdrawal of two irrigations between 45-75 DAS, I4: Stress at pegging, pod filling and kernel development stage; withdrawal of four irrigations from 45-105 DAS and four genotypes as sub plots viz. G1: Dh-86, G2: Dh-101, G3: K-9 and G4: G2-52. Treatments were replicated thrice and laid out in split plot design. Result: Among the water regime, I2 recorded significantly higher WUE (6.2 kg ha-1 mm-1) followed by I1 (control; 5.5 kg ha-1 mm-1). Water regime I2 also recorded significantly higher pod yield and haulm yield (2,857 kg ha-1 4,648 kg ha-1, respectively) along with other yield attributes, but was found at par with control (I1). This study showed that WUE as well as yield of rabi / summer groundnut can be enhanced if crop was exposed only to mild stress by skipping an irrigation at pegging stage out of total seven irrigations. Among the genotypes, Dh-86 with 2,375 kg ha-1 of pod yield performed significantly better over others like Dh-101 (2,215 kg ha-1), K-9 (2,048 kg ha-1) and G2-52 (1,880kg ha-1) suggesting differential response to moisture stress, thus choice of moisture stress tolerant genotypes is equally important to enhance WUE. Interaction between irrigation regime and genotypes showed that Dh-86 (G1) with I2 irrigation regime recorded significantly higher WUE (6.9 kg ha-1 mm-1), pod yield (3,168 kg ha-1) and net return (Rs. 95,655 ha-1) and was found at par with full irrigation regime (I1).