Exploring salt tolerance in Indian mustard [Brassica juncea (L.) Czern. & Coss.] genotypes: A physiological and biochemical perspective

Abstract

Salinity is a crucial problem affecting the productivity of crops across the globe and poses a serious threat to agricultural food production and food security. Salinity stress adversely affects the growth and development of plants by reducing growth attributes, chlorophyll content, and relative water content and further, led to nutritional toxicities and high osmotic stress. The present investigation was employed to assess the response of ten mustard [Brassica juncea (L.) Czern. & Coss.] genotypes under different regimes of salt concentrations (0, 50, 100, 150, 200, 300 mM NaCl) for tolerance potential using principal component analysis (PCA). The PCA analysis of studied attributes found that Pusa Jai Kisan was salt-tolerant and Pusa Bold was susceptible under different salt conditions compared to the rest of the mustard genotypes. The reduction in morphological attributes, the maximum quantum yield of PSII (Fv/Fm), total chlorophyll, and relative water content was lower in Pusa Jai Kisan and higher in Pusa Bold with increasing concentrations of salinity. In addition, the accumulation of Na+ and Cl‒ ions was increased with increasing salinity stress. Based on growth performance, ten genotypes of mustard were ranked depending on their tolerance to salinity stress: Pusa Jai Kisan > Pusa Mustard 30 > Pusa Jagannath > Pusa Mustard 28 > Pusa Vijay > Pusa Tarak > Pusa Mustard 25 > Pusa Mustard 27 > Pusa Mahak > Pusa Bold, respectively. Thus, PCA analysis can be used as a powerful tool for the identification of tolerant and susceptible genotypes under salinity stress. The understanding of mustard responses towards salinity stress could help in the selection of tolerant genotypes and this selection may play a crucial role in further improving the effectiveness of breeding.