No abstract

In this paper, CO was taken as an example to analyze the impact mechanism of temperatures and the temperature correction formula of its response factor was derived. The real temperature properties of SF6 and CO were studied using a non-resonant PA spectroscopy device designed by our team.

High temperature at owering stage of rice causes low spikelet fertility and low yield. To cope with high temperature stress brought by climate change, two strategies were proposed to develop heat-resilient rice varieties. One is to escape the high temperature by owering early in the morning, another is to enhance tolerance to high temperature stress per se. Two promising QTLs for early morning owering (qEMF3) and heat tolerance (qHTSF4.1) were introgressed into IR64 background, and near isogenic lines (NILs) IR64+qEMF3 (IR64EMF3) and IR64+qHTSF4.1 (IR64HT4) were developed in previous studies. In this study, a QTL pyramiding line IR64+qHTSF4.1+qEMF3 (IR64HT4EMF3) was developed by marker assisted selection of the progenies of previous NILs. The NILs were subjected to different high temperature regimes in the indoor growth chambers and different locations in the eld. In the indoor growth chambers, when high temperature starts early (before 11:00 am), IR64HT4 and IR64HT4EMF3 had higher spikelet fertility than IR64EMF3; when high temperature comes later (after 11:00 am), IR64EMF3 and IR64HT4EMF3 had higher spikelet fertility than IR64HT4. The owering pattern of the IR64HT4EMF3 was earlier than IR64HT4, but similar to IR64EMF3 in the glasshouse, eld and indoor growth chambers. IR64HT4EMF3 showed higher spikelet fertility than IR64EMF3 and IR64HT4 in the eld in the Philippines. Thus, combination of early morning owering and heat tolerance QTLs is an elegant breeding strategy to cope with future extreme climate. Key MessageThis study demonstrated that pyramiding of early morning owering and heat tolerance QTLs (qEMF3 and qHTSF4.1) in rice is an e cient approach to maintain high spikelet fertility under high temperature stress at owering stage.