Effect of polyethylene glycol (PEG) 6000 on germination and seedling growth of pearl millet [Pennisetum glaucum (L.) R. Br.] and LD50 for in vitro screening for drought tolerance

Abstract

Millet crop is an important cereal for food security and the fight against poverty and malnutrition in the arid Sahel. It is a staple grain for millions of people in West Africa and India. It has the advantage of tolerating drought-prone environments and low fertility soils. Recent climate change exacerbates the phenomenon of drought; hence, improving pearl millet drought tolerance became a present necessity. The present study was conducted to determine an in vitro screening method for drought tolerance, based on the use of polyethylene glycol (PEG) of molecular weight 6000 Da. This experiment was carried out with one millet genotype (HKP), promoted by the agricultural official services. The effect of PEG6000, with varying concentrations from 0 to 40% (w/v), on germination percentage, coleoptiles emergence, shoot and root length, shoot and root weight and root/shoot ratio were analyzed. Data were used to determine the lethal dose for 50% growth inhibition (LD₅₀), which was applied for drought tolerance screening. Significant differences were observed for all the characters under different PEG concentrations. LD₅₀ was 262 g/L for the germination percentage and 242 g/L for coleoptiles emergence.

Keywords: Pearl millet, water stress, polyethylene glycol, LD₅₀

African Journal of Biotechnology, Vol 13(37), 3742-3747