Achim Dobermann, deputy director general for research at the International Rice Research Institute (IRRI; http://irri.org), and Leigh Vial, head of IRRI's experiment station, begin IRRI Agronomy Challenge II. It is the continuation of a special project in which they demonstrate how to grow a productive rice crop in a 25 x 100-meter field on IRRI's research farm.
In this installment, Achim harvests the hybrid side of the plot and evaluates the crop.
Commentary from Achim:
We've harvested a great crop this year because we did almost everything right and the weather was good. That the numbers are in we must report another disappointment of not being able to reach our yield goals.
Let's just concentrate on the naked facts and come back in a couple of weeks with a deeper analysis. We had two beautiful harvest days and using a modern rice combine made it very easy to harvest the hybrid variety on April 5, and the inbred variety one week later. No lodging this time and the combine generally did a good job in terms of producing clean grain.
So, things seemed alright, but driving through on the combine it already dawned on me that we just didn't seem to have enough grain out there for a high yield. There were many good areas, but also many poor patches. In a nutshell, measured as total grain weight for the whole plot and including all gaps or empty patches, the inbred yielded 6.57 tons/ha (expressed at 14% moisture content) whereas the hybrid yielded only 5.62 tons/ha.
In transplanted rice fields grain yield usually has a coefficient of variation of about 15-20% and follows a normal frequency distribution. So, what that means is that we actually achieved our target yield of 7 t/ha on about one third of the inbred field area. In the case of the hybrid, however, the yield target of 7.5 t/ha was only achieved in a few places, less than 5% of the field.
International Rice Research Institute
5 years, 5 months ago