Time of Flowering Affects Grain Quality and Spikelet Partitioning Within the Rice Panicle

Abstract

Anthesis of spikelets in the panicle of a tall indica rice cultivar, Kajalghara, was completed within a period of 7 days. Development progressed in basipetal fashion from the spikelets of the uppermost primary branch of the panicle to the lowermost. According to the timing of onset of anthesis, spikelets of the panicle were segregated into seven groups. Dry mass accumulation and starch and assimilate (soluble carbohydrates and amino acids) contents of each group were studied from anthesis to grain maturity. Spikelets that anthesed earlier produced better quality grains and also had higher sink efficiency in converting soluble assimilates into reserve structural matter than those which anthesed later. These results rule out deficiency in supply of assimilates as a cause of partial filling of grains in the rice panicle. The study also emphasises the need for improving the percentage of high density grains in the rice panicle to maximise the use of available assimilates and enhance the grain yield potential of the plant.

Effects of Time of Nitrogen Fertilizer Application on the Growth and Productivity of Rice (Oryza Sativa L) in Fogera Plain, North Western Ethiopia

“…This result showed that split application of nitrogen fertilizer at panicle initiation growth stage decreases number of un-filled spikelet's per panicle as compared to the control treatment. This result is in agreement with findings of many authors (Mohapatra et al, 1993;Yang et al, 2006). Time of nitrogen fertilizer application statistically influenced total dry biomass (P<0.001) ( Table 2).…”

Approaches to achieve high grain yield and high resource use efficiency in rice

“…In general, earlier-flowering superior spikelets, usually located on apical primary branches, have fast-filling and heavier grains. Later-flowering inferior spikelets, on the other hand, are usually located on proximal secondary branches, and are either sterile or have poor and slow-filling grains that are unsuitable for human consumption [32,33] . The problem of slow-filling grain in inferior spikelets is even worse in newly bred super rice cultivars, although they generally show a yield potential of 8%-20% more than other rice cultivars [28,34] .…”

Activities of Enzymes for Sucrose-Starch Conversion in Developing Endosperm of Rice and Their Association with Grain Filling in Extra-Heavy Panicle Types

“…In addition, the rate of the grain-filling process after anthesis was evaluated as another parameter of the effi ciency of grain fi lling, because it should be related directly to the transport of photosynthates. The position of the spikelets examined in a panicle was also taken into account, as the effi ciency of grain fi lling is strongly dependent on the spikelet position in a panicle (Mohapatra et al, 1993;Ishimaru et al, 2003).…”