Abstract
In rice (Oryza sativa L.), yield is related to characteristics of branches and spikelets. To investigate the effects of late sowing date on differentiation and degeneration of spikelets in rice, field experiments were conducted in Chongzhou and Hanyuan, China. Differentiation and survival of branches and spikelets in Hanyuan were lower than that of Chongzhou, whereas degeneration was greater than that of Chongzhou. In Chongzhou, sowing date affected differentiation and survival of primary, secondary, and total branches, as well as differentiation and degeneration of secondary and total spikelets. In Hanyuan, sowing date affected degeneration of secondary and total branches, and the survival and degeneration of primary spikelets. Late-sown plants experienced higher temperatures in the jointing to heading period, and there were higher sunshine hours. Rainfall and humidity were higher in Chongzhou, but lower in Hanyuan. Late sowing increased differentiation, degeneration, and survival number of branches and spikelets in Chongzhou. However, in Hanyuan, late sowing increased differentiation and degeneration of branches, but decreased survival of branches, which reduced spikelet differentiation and degeneration, resulting in fewer branches. Thus, the key to higher yield in Chongzhou was to increase differentiation of spikelets, whereas in Hanyuan, it was to reduce degeneration of branches and spikelets.
Highlights
As one of the three major global cereal crops, rice (Oryza sativa L.) is the most important and oldest food species in the genus Oryza
The aim of this research was to investigate the effects of delayed sowing dates on various yield parameters in indica rice grown under different ecological conditions
There was a negative correlation between the yield at Hanyuan and the retrogressed and retrograded percentage of secondary and total branches and spikelets. This indicates that the key to increasing yield is to reduce degeneration of spikelets and branches by ensuring the proper amount of spikelet differentiation under the ecological conditions present at Hanyuan
Summary
As one of the three major global cereal crops, rice (Oryza sativa L.) is the most important and oldest food species in the genus Oryza. Half of the world’s population, including most people living in East and Southeast Asia, eat rice as a daily staple [1]. According to the UN, the world’s population will reach 9.6 billion by 2050. If global population growth continues at its current rate without any change in food productivity and dietary preferences, there will be severe food shortages [2] [3]. China is a large agricultural country with a large population. With the growth of the population, China will need to produce about 20% more rice by 2030 in order to meet its domestic needs if rice consumption per capita stays at the current level [4]. Increasing rice yield per unit area is a priority
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