Identification of waterlogging stress tolerant maize (Zea mays L.) hybrids using different selection indices

About 15% of the maize-cultivating areas are affected by severe waterlogging stress or flooding in South and Southeast Asia, causing yearly production losses approximately by 25∼30% (Chen et al., 2014). In general, maize is highly sensitive to excess soil moisture mostly at early vegetative stages. Waterlogging at early vegetative stages results in severe reduction in traits such as plant height, days to flowering and maturity, dry matter accumulation along with grain yield potential (Liu et al., 2010). In India, only 15% of the maize growing area is under proper irrigation (Sah et al., 2020). India projected 0.9 mha as waterlogging affected area (MoA&FW, GOI, 2018). It was reported that 12% of global cultivated land was severely affected by waterlogging stress that resulting in a nearly 20% decline in crop production through limiting plant growth and development by altering morphological, physiological, and anatomical mechanisms (Abiko et al., 2012 and Luan, 2018). The contingent flooding by continuous rainfall coupled with inadequate drainage and elevated groundwater table are the key constraints in maize production in Asian tropics and other parts of the world (Singh et al., 2017). Over the years the total maize cultivating area in South and Southeast Asia alone are frequently affected by waterlogging problems. Therefore, it is necessary to focus on identification of tolerance in maize against excessive soil moisture and waterlogging in India to meet the increasing demand of grain yield production.