Influence of tiller heterogeneity on yield components of rice grown under different nitrogen regimes

Increase in rice yield under excessive nitrogen (N) supply is negligible, hence it is necessary to analyze the limiting factors via yield components. The present study was carried out during 2014 and 2015 growing seasons in order to quantify the yield componenents of different types of tiller at various N levels. Tillers were divided into three different types (superior, medium and inferior) based on their productivity. The results indicated that the quantitative proportions and yield contributions were decreased in superior tillers, increased in the inferior tillers, while remained stable in the medium tillers with increasing supply of N fertilizer. The increased rate of spikelets per panicle in the superior tillers was higher under all N application levels; however, a high quantitative proportion and the lower number of spikelets per panicle of the inferior tillers might have resulted in the reduced population of spikelets per panicle. The rates of grain filling percentage and grain weight in medium and inferior tillers were decreased with increasing N applications, which led to a decrease in population grain filling and grain weight. The present study suggested that the enhancement of grain filling and weight of the inferior tillers would be an effective approach to further improve the per acre yields of rice. The acquisition of more accurate yield component data, in the perspective of tiller, might be helpful for researches regarding the development of augmented rice breeding architectures.