Relationship between Date of Anthesis and Grain Weight on the Panicle of Rice

Abstract

The relationship between the difference of date of anthesis (Δt) and that of final grain weight (Δw)was studied by observing pairs of spikelets at various positions on the panicle of rice cultivers, 'Nipponbare' and 'Musashikogane'. A high negative correlation was found between the deviation of Δt (Δt-Δt^mode ; Δt^mode was the most frequently observed Δt) and that of Δw (Δw-Δw^mode ; Δw^mode is the Δw when Δt = Δt^mode), in all pairs of spikelets both on the same (Fig.2) and on different (Fig.3) primary rachis branches. Thus, the results suggest that early flowering spikelets bear larger grains than later flowering spikelets on the corresponding position of primary rachis branch. This fact is probably because early flowering augments nutritional distribution.