Comprehensive evaluation, analysis of mechanisms and the prediction of salinity tolerance in pomegranate

Abstract

There are gaps in our comprehension about irrigation water salinity tolerance and the complex mechanisms involved especially in pomegranate. Therefore, the current study was conducted with six commercial cultivars (Jalore seedless, Mridula, Bhagwa, Phule Arakata, Ganesh-137 and Wonderful) under shade net conditions. In a pot culture experiment, about three months old, rooted cuttings were subjected to natural underground saline water irrigations (EC 1.5, 3.0, 4.5 and 6.0 dS m−1) at Punjab Agricultural University Research Station, Abohar, India. EC 6 dS m−1 was found to be the most appropriate salinity level for the evaluation. Salinity response index for different parameters was calculated with respect to good quality canal water (EC 0.12 dS m−1) and subjected to further analysis. The comprehensive evaluation index (D-value) for tested cultivars revealed the following order of salinity tolerance: Bhagwa > Wonderful > Mridula > Jalore Seedless > G-137 > Phule Arakata. Water use efficiency, superoxide dismutase activity, cell turgor and cell membrane stability were identified as predictors of salinity tolerance. We also observed that targeting Cl rather than Na could be more promising to breed salinity tolerant pomegranate cultivars. Empirical relationship between ‘D-value’ and the predictors was also established with greater probability of prediction.