Research shows that the highest maize yields come from uniform stands of plants which emerge at the same time and grow to produce even plants. Three factors interact during germination and emergence and together determine how well a maize crop establishes. These are seed quality, hybrid genetics and the growing environment.
While it is possible to influence some environmental factors (e.g., soil compaction and planting date) others are virtually impossible to control. In New Zealand, spring growing conditions can be challenging with fluctuating temperatures and saturated soils. For the past three seasons, the quest for more uniform maize seed emergence has led to increased seed quality research to help characterise the performance of individual Pioneer hybrids under cold, wet emergence conditions.
A number of tests can be used to quantify maize seed quality:
While warm germination tests - carried out according to International Seed Testing Association (ISTA) protocols - provide a good indication of paddock germination under ideal conditions, the proprietary Pioneer Stress Test (PST):
Pioneer maize hybrids (untreated and treated) were tested for physical purity, genetic purity, warm germination and through the Pioneer Stress Test (PST). This allowed us to characterise the relative vigour of individual hybrids under the toughest germination conditions.
In spring 2019, 24 hybrids were planted ultra-early at twice the normal planting depth (8.5 cm) into cold wet soils. There were a total of three Waikato and three lower North Island sites giving a total of 36 replicates per hybrid. The Pioneer Research Team monitored the sites and measured the rate of emergence as well as final plant stand count. Due to the challenging establishment conditions, the mean established plant population was 82% of the planting rate. There were, however, significant differences between hybrids with an established population range of 70-90%.
All Pioneer seed supplied to the market is expected to establish excellent plant stands if planted well and under normal germination conditions. Data collected from the laboratory seed quality testing exercise and the field stress emergence trials, referred to above, were used to develop the Pioneer Stress Emergence Ratings. These ratings indicate each hybrids ability to establish under challenging cold, wet growing conditions. The table below groups hybrids into three classes as a result of this research.
Growers can be confident that every bag of Pioneer® brand maize seed they plant has been thoroughly tested in this extensive screening program and meets Pioneer’s industry-leading standards.