Farm Table says:
What is the problem?
Rice florets are susceptible to high-temperature damage at anthesis, but rice production remains stable in the Riverina region of Australia even when the air temperature during flowering exceeds 40 degrees C.
What did the research involve?
To identify the mechanism that supports rice production under these conditions, we examined sterility and pollination in relation to microclimate and panicle temperature in an extreme hot paddy field in the Riverina region of New South Wales. In windy below 40 degrees C weather, the panicle temperature was below 38 degrees C at the windward edge of the crop but around 35 degree C inside the crop, probably because of strong transpirational cooling due to the extremely dry wind
What were the key findings?
Pollen from the windward edge of the crop showed extremely poor germination, yet that from inside the crop showed sufficient germination for fertilization. Moreover, sterility inside the crop was significantly lower than that at a windward edge.
We concluded that the wind with large vapor pressure deficit enabled stable rice production under the extreme heat during flowering. The hot, dry wind induced floret sterility on the windward edge of the filed. The main direct cause of sterility was the low percentage germination of pollen grains on the stigma.