Effects of source-sink regulation and nodal position of the main crop on the sprouting of regenerated buds and grain yield of ratoon rice

Aibin He; Min Jiang; Lixiao Nie; Jianguo Man; Shaobing Peng

doi:10.3389/fpls.2023.1043354

Effects of source-sink regulation and nodal position of the main crop on the sprouting of regenerated buds and grain yield of ratoon rice

Front Plant Sci. 2023 Mar 27:14:1043354. doi: 10.3389/fpls.2023.1043354. eCollection 2023.

Authors

Aibin He¹, Min Jiang¹, Lixiao Nie², Jianguo Man¹, Shaobing Peng¹

Affiliations

¹ MOA Key Laboratory of Crop Ecophysiology and Farming System in the Middle Reaches of the Yangtze River, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, China.
² Research Center for Physiology and Ecology and Green Cultivation of Tropical Crops, College of Tropical Crops, Hainan University, Haikou, Hainan, China.

Abstract

Ratoon rice (Oryza sativa L.) is the production of a second season rice that utilizes the dormant buds surviving on the stubble left behind after the harvest of the main crop. However, the sprouting mechanism of regenerated buds at separate nodes is rarely reported. Field experiments were conducted to examine the effects of leaf-cutting and spikelet thinning on the sprouting of regenerated buds at the separate node, the contributions of regenerated panicles at the separate node to the total grain yield in the ratoon crop, and the associated mechanism. The results showed that the contribution of separate node yields to the total grain yield in the ratoon crop was D2 (panicles regenerated from the 2^nd node from the top) >D3 (panicles regenerated from the 3^rd node from the top) >D4 (panicles regenerated from the lower nodes below the 3^rd node), and the contribution of D2 and D3 made up approximately 80% of the total yield in the ratoon crop. In addition, the effect of leaf-cutting treatment and spikelet-thinning treatment on the grain yield of ratoon season was mainly realized by regulating the relative contribution rate of D2 and D4 grain yield to the total yield of ratoon season. Further analysis indicated that the sprouting of regenerated buds at the D2 node was mainly affected by the content of CTK, while D3 was mainly regulated by GAs and CTK, and D4 was mainly regulated by ABA and CTK. However, only the CTK content in stems and buds was positively correlated with single bud length and bud number at each nodes. These results indicated that CTK might be the main signal regulating the sprouting of regenerated buds and the grain yield at separate nodes, which might change the transport of assimilates to stems and buds.

Keywords: cytokinin; leaf-cutting; ratoon rice; regeneration rate; spikelet-thinning.

Grants and funding

This work is supported by the National Natural Science Foundation of China (Project No. 31971840), and Research Initiation Fund of Hainan University (Project No. KYQD (ZR) 19104).