Screening Method and Response Surface Design for Drying Hybrid Maize to Maintain Seed Quality

Hybrid maize ( Zea mays L.) ear drying is an expensive process and considered a bottleneck in seed production. The seed industry does not have an effective procedure to screen germplasm for drying temperature sensitivity and optimum drying conditions. The aims of this paper were (i) to develop a simple, rapid, and reliable technique to screen drying temperature tolerances and (ii) to exploit the response surface design (i.e., predictive model of the relationship between factors and the response) to identify optimum drying temperatures. Trials consisted of screening experiments, in which ears were constantly dried at 35 and 45°C, and response surface experiments, in which samples were subjected to different drying temperatures in two phases (30, 35, and 40°C for the first and 35, 40, and 45°C for the second drying phase). Standard germination, cold, and accelerated aging tests were conducted to measure the effect of drying regimes on seed quality. Drying hours and rates were determined. Drying hours and rate were reduced 36 and increased 44% in the stress treatment relative to the control, respectively. Genotypes differed in drying temperature tolerances only when the cold test was used in the analyses. The response surface design allowed identifying specific temperature combinations for the first and the second drying phases that optimized quality parameters. The results of this study can be useful tool for seed industries to optimize their drying process and seed quality.