Genotypic variability in physiological, biomass and yield response to drought stress in pigeonpea

Abstract

Three pigeonpea (Cajanus cajan L. Millsp.) genotypes-GT-1, AKP-1 and PRG-158 with varying crop duration, growth habit and flowering pattern were evaluated for variability in their response for drought stress. Drought stress was imposed at initiation of flowering and the observations on biomass and seed yield parameters were recorded at harvest. The magnitude of response of individual component to drought stress was found to be genotype specific. Drought stress significantly decreased photosynthetic rate (P N ), transpiration rate (Tr) and relative water content (RWC) in all the genotypes, however the magnitude of reduction differed with genotype. With drought stress, the reduction of P N was highest in GT-1 while reduction in Tr was highest in PRG-158. The genotype AKP-1, accumulated significantly higher concentrations of osmotic solutes especially proline under water deficit stress, this facilitated it to maintain higher relative water content (RWC) and lower malondialdehyde (MDA) content as compared to other genotypes. Drought stress also impacted biomass production and their partitioning to vegetative and reproductive components at harvest. There was significant variability between the genotypes for seed yield under drought stress while it was non-significant under wellwatered condition. Drought stress enhanced flower drop and decreased flower to pod conversion resulting in reduced pod number and seed number in PRG-158 and GT-1. The genotype AKP-1 recorded superior performance for seed yield under stress environment due to its ability in maintaining pod and seed number as well as improved test weight (100 seed weight). Under drought stress, significant positive association of seed yield with proline, seed number, pod number and test weight clearly indicating their role in drought tolerance.

Response of morpho-physiological traits to drought stress and screening of curly pepper (Capsicum annuum) genotypes for drought tolerance

“…The interaction between genotypes and stress conditions significantly affected the photosynthetic rate, stomatal conductance, intercellular CO2 concentration, transpiration rate, and the ratio of intercellular CO2 concentration and intracellular CO2 concentration (Ci/Ca), mesophyll conductance, and intrinsic water use efficiency. Our results were similar to those reported by Vanaja et al (2015) in Cajanus cajan L. and Liu et al (2015) in Panicum virgatum L. Genotypes responses to drought stress were different because of differences in their genetic potential on drought tolerance.…”

Trait-based responses of seven annual crops to elevated CO2and water limitation

“…We measured leaf chlorophyll content as Chlorophyll Fluorescence Ratio, or fluorescence emission ratio of intensity at 735 nm/700 nm, with an Opti-Sciences CCM-300 (Opti-Sciences, Inc, Hudson, NH, USA). Photosynthetic yield relates to the efficiency of plants in assimilating carbon and has a positive correlation with crop yield (Fischer et al, 1998). Water stress can reduce photosynthetic rate and efficiency (Kawamitsu et al, 2000; Nyachiro et al, 2001), with subsequent negative impacts on crop yield (Vanaja et al, 2015). We measured quantum yield of photosystem II with an Opti-Sciences OS1p (Opti-Sciences, Inc, Hudson, NH, USA).…”

Drought in Indian perspective, its impact on major crops and livestock and remedial measures

“…Though there had been reduction in the relative water content, photosynthetic apparatus was not impacted showing ability of chickpea to maintain turgor even under water stress conditions (Basu et al, 2004). Drought stress in pigeonpea led to reduction in relative water content, stomatal conductance, transpiration rate, total chlorophyll content, enhancement in proline content, superoxide dismutase, malondialdehyde and peroxidase activity, reduction in specific nitrogenase activity and leghaemoglobin content (Nandwal et al, 1991;Kumar et al, 2011;Vanaja et al, 2015). Flowering stage is most sensitive stage for drought stress in pigeonpea leading to 48% reduction of yield and upto 62% when combined with drought at pre-flowering (Lopez et al, 1996;Nam et al, 2001).…”