In vitro screening of gamma irradiated rice variety MR263 for drought tolerance using polyethylene glycol

Abstract

Fluctuating weather conditions and climate change are affecting agricultural production worldwide including rice yield. Combined with the increasing population and decreasing land space for agricultural practices, biotechnological solutions are needed to improve the livelihood of farmers and the country’s food security. Rice seeds of cv. MR263 were irradiated with gamma rays at doses 300, 350, and 400 Gy to evaluate their response to ionizing radiation on their growth. The irradiated seeds were germinated on MS media, and the seedlings were grown in media with polyethylene glycol 6000. It was found that most of the germination percentage decreased gradually with increasing radiation dosage. Shoot lengths reduced with radiation dose, per treatment. The root length was highest at dose 350 Gy (9.5 cm) compared to the other irradiated treatments. Fresh and dry weights generally decreased with increasing dosage and water stress levels except for dose 350 Gy. The highest fresh (354 mg) and dry weight (56.7 mg) were observed in seedlings irradiated with a dose of 350 Gy treated with 0% PEG and 10% PEG respectively. The content of proline and carbohydrates increased as the radiation doses and PEG concentrations increased where the highest proline (11.8 µM/g) was observed in 350 Gy + 20% PEG. While the highest carbohydrate content (9.3 mg/g) was observed in 400 Gy+ 20% PEG. It was concluded that seedlings radiated with 350 Gy showed promising results indicating tolerance to drought stress, due to their improved morphological and biochemical traits.