Assessing Salinity, Drought and High Temperature Stress in Maize (Zea mays L.) and Wheat (Triticum aestivum L.) Varieties: Theoretical Combination as Multifactorial Stress

Maize and wheat are two important cereal crops for the food security of the world population. However, constant climate change and the intensification of anthropic activities have intensified the emergence of stressful environmental in the various agricultural production systems around the world. Therefore, in this study we evaluate the chlorophyll content, photosynthesis, transpiration and grain yield of maize and wheat crops exposed to soil salinity, drought and high temperatures and determine the damage intensity of these stressing conditions and the theoretical multifactorial damage intensity. Field experiments were conducted during the 2022 and 2023 agricultural seasons in the Yaqui Valley, Sonora, Mexico. The treatments consisted of the cultivation of maize and wheat in three stressful production environments (soil salinity, drought and high temperatures) and a non-stressful production environment (Control), with four repetitions. The tolerance and intensity index of abiotic stresses, as well as the intensity of theoretical multifactorial stress (salinity, drought and high temperatures), for morphological traits and grain yield, were calculated. The results reported that physiological traits and yield of maize and wheat are severely affected by drought stress conditions. High temperatures are the second abiotic stress factor that most limits physiological traits and grain yield of maize and wheat crops, being more harmful than soil salinity. The theoretical multifactorial stress has a greater negative impact on the yield of the elite maize and wheat varieties. The sum of a stressful environmental factor increases the intensity of multifactorial stress on grain yield of both cereal crops, especially for maize crop.