Morphological characterization of the rice genotypes at early growth stages and determination of better parent heterosis for salinity tolerance traits under NaCl stress

Abstract

Soil salinity is a serious problem for agricultural productivity throughout the world. The Crops grown on saline soils suffer from ions toxicities, nutritional disorders, osmotic stress, and ultimately leads to the reduced yield. Rice is an essential food crop that is consumed by more than half of the world population but rice is at risk of salt stress due to increasing salinity. Understanding the causes and related concerns of salinity on rice yield and growth will improve our ability to compensate for its adverse effects through short or long-term adaptation approaches. In the following study, two experiments were performed. The genotypes were screened at germination and seedling stages in the first experiment to select 5 NaCl responsive genotypes including 2 NaCl tolerant, 2 moderately NaCl tolerant, and 1 NaCl susceptible. These genotypes were selected based on the gain in radical length (RaL), plumule length (PlL), radical fresh weight (RaFW), plumule fresh weight (PlFW), radical dry weight (RaDW),  plumule dry weight (PlDW), at germination stage and, at seedling stage root length (RL), dry root weight (DRW), fresh root weight (FRW), shoot length (SL), fresh shoot weight (FSW) and dry shoot weight (DSW), were determined from growing seedlings. In the second experiment, the selected genotypes were hybridized with two modern cultivars following the line into tester mating design. The F1 hybrids were evaluated based on the above-mentioned salinity tolerance traits at the germination and seedling stages. The obtained data were used to determine the better parent heterosis for the salinity tolerance traits.