Evaluation of salinity tolerance in Tamil Nadu and Kerala's popular traditional rice varieties during germination and early growth stages

Abstract

Rice is a key food crop worldwide. Drought, salinity, and flooding stress are the most common abiotic stresses in rice crops, and they result in large production losses each year. The present study aimed to assess the salinity tolerance in the early growth phases of 14 rice varieties, including local varieties from the Indian states of Tamil Nadu and Kerala were investigated at NaCl concentrations of 0 mM (control), 100 mM, 150 mM, 200 mM, and 250 mM. Salt tolerance was examined in selected varieties using the Petri plate method in a controlled environment (24 ± 2 ºC) in a plant growth chamber. At 7 days after sowing (DAS), data were statistically analysed for germination percentage, root length, branch length, and total seedling length. The vigour index is also determined for seven DAS seedlings. Lower magnitude values in germination percentage, root length, shoot length, and total seedling length resulted in shorter shoot and root lengths across all kinds. At 250 mM NaCl, Karunguruvai had the highest germination percentage (85%), followed by TPS-5 (50%). Furthermore, at 150 mM NaCl concentration, the traditional rice variety karunguruvai showed 100% seed germination, followed by mappilai samba and TPS-5 (90%), arupatham kuruvai (85%), and pongar (80%). At a 250 mM NaCl solution, karunguruvai exhibits much better rates of root and shoot growth than other types. As a result, the current study suggests that Karunguruvai could be utilised to further investigate salinity's effect on growth processes and physiological repercussions at an advanced stage of development.