Morpho-physio-biochemical and Molecular Characterization of Selected Potato (Solanum Tuberosum L.) Varieties Under Drought Stress

Abstract

Potato (Solanum tuberosum L.) is considered as an important cash crop of the world and also known as apple of soil. It provides food for millions of people across the globe with being the 4th largest produced crop. Drought is one of the major stress factors affecting the growth and development of potato plants. In this study, we have selected 5 Indian potato varieties and supplemented them with 2 different drought treatments viz., allowed them to undergo heavy drought stress and application of aquasorb at the time of sowing at the rate of 30Kg/ha. Both the treatments were subjected for 15 days of drought stress by water withholding at tuber initiation stage which is known to be the most vulnerable stage due to drought stress. The experiment was conducted in CRD pattern using experimental pots at the rain out shelter of Department of Agriculture Biotechnology. Various morpho-physiobiochemical parameters regarding drought stress responses of plant were selected, measured and compared within the varieties after the drought stress period was completed. Also, seven drought related gene specific marker were synthesized using bioinformatics tools and were used for molecular characterization of selected potato varieties. The study suggests that, drought has negatively impacted on all the varieties used in the experiments regardless of their stress response nature. The impact of drought stress varied among the plant varieties, where K. Thar-1, a drought tolerant variety under drought stress was found significantly superior over K. Pukhraj, K. Bahar, K. Chipsona-1 and K. Chipsona-1 in the morpho-physio-biochemical parameters namely no. of compound leaves per plant (10.3), no. of tubers per plant (18.67), weight of tubers per plant (238.89gm), top biomass weight per plant (336.83gm), root biomass weight (20.7gm), average stolon length (10.8cm), chlorophyll content(31.80), leaf area index (1.52), relative water content (56.45%), sucrose content (381.49mg), reducing sugar content (73.87mg), proline content (28.83μmols), catalase activity (24.57U), peroxidase activity (61.45ΔA/min) and abscisic acid content (256.49pmol). In aquasorb treated drought stressed conditions, all the varieties shown great resilience and were found to be significantly superior over drought stressed conditions. This experiment suggest that Aquasorb can help to minimize the losses occurred in crop production. Molecular characterization of these selected potato varieties gave three polymorphic bands and seven monomorphic bands at an average pf 1.43 bands per primer. The dendrogram using bioinformatics tools explains inter-varietal hierarchical relationship.