Breeding for Drought Tolerance in Maize

Drought and high temperatures limit maize production in many parts of the world. Breeding drought and heat tolerant maize hybrids is a key to increase water use efficiency and reduce the yield and quality loss due to drought stress. Drought tolerance is a complex trait. Accurate screening for drought tolerance depends on the timing, intensity and duration of drought stress. A major effort of our breeding program is to develop maize germplasm tolerant to abiotic and biotic stresses. With the low rainfall in West Texas and subsurface drip irrigation systems, we have developed a field screening methodology to evaluate a large number of lines and hybrids for drought and heat tolerance. Tremendous genetic variation exists in maize germplasm in response to drought and heat stress. We make breeding populations by crossing tropical and sub-tropical germplasm with elite temperate adapted lines and then select superior drought tolerant genotypes under controlled drought stress conditions. Drought-tolerant maize lines and hybrids have stronger root systems, higher hydraulic lift capacity, better stay green trait, less barren plants, and lower aflatoxin.