Pollination is a critical period for development of corn and yield potential. Pollen shedding occurs normally over a two-week period. For kernel development, silks must first emerge and be fertilized by viable pollen. Silks will grow about 2,54 to 3,50 cm per day and will continue to elongate until fertilized. Temperatures higher than 35oC with relatively low humidity will remove the moisture from the silks to become completely dry. Although this will not have an impact on the silk elongation rate, pollen is no longer viable once temperatures reach mid 30oC or higher, especially with low relative humidity. Pollen shedding usually occurs from early to mid-morning when temperatures are generally lower.
Drought stress slows silk elongation but accelerates pollen shedding. This can result in pollen shedding occurring before the silk emergence. Any stress such as too little watering, low soil fertility, or high plant population can delay silking two or more weeks. This reduces the seed set if pollen is no longer available. Normally the pollen of one plant is sufficient for about 10 plants, this provides a small compensation and improves the opportunity for fertilization in stressful conditions.
High temperatures will not severely stress sweetcorn/corn pollination if the soil moisture is enough. Drought stress along with high temperatures during pollination and silking can have serious effects. If dry-hot conditions continue over the pollination period, expect to see differences in fields based on management practices and different hybrids (cultivars).
- Farming practices that protect soil moisture such as reduced till will improve a crop’s performance during drought.
- It’s possible that early-season hybrids or early maturing hybrids could do better than other hybrids if pollination occurs before temperatures soar or moisture reserves are depleted. It’s impossible to predict when stressful conditions will occur from year to year, but using a quicker maturing hybrid could limit some of the issues mentioned above.
Hygrotech’s new range fits perfectly into the earlier maturing hybrid segment, with Caramelo F1 maturing in 70 – 75 days. Khan F1 is short on its heels maturing within 75 – 82 days. Most of the current cultivars used in South Africa average maturing of 85 – 90 days.
Hygrotech’s sweetcorn hybrid segment:
Recommended plant population 60 – 65 000 plants per hectare, could help keep the soil moisture (Plant/leave cover) once the soaring heat units arrive. This provides enough irrigation being done. We are already seeing unprecedented heat waves as the El Niño is set to return in 2025.
