Higher Grain-Filling Rate in Inferior Spikelets of Tolerant Rice Genotype Offset Grain Yield Loss under Post-Anthesis High Night Temperatures

作     者：Nitin SHARMA Bhupinder SINGH Subbaiyan Gopala KRISHNAN Haritha BOLLINEDI Pranab Kumar MANDAL Milan Kumar LAL Prakash Kumar JHA P.V.Vara PRASAD Anjali ANAND Nitin SHARMA;Bhupinder SINGH;Subbaiyan Gopala KRISHNAN;Haritha BOLLINEDI;Pranab Kumar MANDAL;Milan Kumar LAL;Prakash Kumar JHA;P.V.Vara PRASAD;Anjali ANAND

作者机构：Division of Plant PhysiologyIndian Council of Agricultural Research(ICAR)-Indian Agricultural Research Institute(IARI)New Delhi 110012India Division of Environment ScienceICAR-IARINew Delhi 110012India Division of GeneticsICAR-IARINew Delhi 110012India ICAR-National Institute for Plant BiotechnologyNew Delhi 110012India Division of Crop Physiology and BiochemistryICAR-National Rice Research InstituteCuttack 753006India Department of Plant and Soil SciencesMississippi State UniversityStarkvilleMS 39762USA Feed the Future Innovation Lab for Collaborative Research on Sustainable IntensificationKansas State UniversityManhattanKS 66506USA Department of AgronomyKansas State UniversityManhattanKS 66506USA 

出 版 物：《Rice science》 (水稻科学（英文版）)

年 卷 期：2024年第31卷第5期

页      面：572-586,I0059-I0061页

核心收录：

学科分类：09[农学] 0901[农学-作物学] 

基　　金：the financial assistance provided by ICAR-IARI in the form of IARI Fellowship and Department of Science and Technology  Innovation in Science Pursuit for Inspired Research during the PhD programme 

主　　题：high night temperature inferior grain pasting property radiolabeled sugar superior grain 

摘      要：Increased nighttime respiratory losses decrease the amount of photoassimilates available for plant growth and yield. We hypothesized that the increased respiratory carbon loss under high night temperatures(HNT) could be compensated for by increased photosynthesis during the day following HNT exposure. Two rice genotypes, Vandana(HNT-sensitive) and Nagina 22(HNT-tolerant), were exposed to HNT(4 ℃ above the control) from flowering to physiological maturity. They were assessed for alterations in the carbon balance of the source(flag leaf) and its subsequent impact on grain filling dynamics and the quality of spatially differentiated sinks(superior and inferior spikelets). Both genotypes exhibited significantly higher night respiration rates. However, only Nagina 22 compensated for the high respiration rates with an increased photosynthetic rate, resulting in a steady production of total dry matter under HNT. Nagina 22 also recorded a higher grain-filling rate, particularly at 5 and 10 d after flowering, with 1.5- and 4.0-fold increases in the translocation of ^(14)C sugars to the superior and inferior spikelets, respectively. The ratio of photosynthetic rate to respiratory rate on a leaf area basis was negatively correlated with spikelet sterility, resulting in a higher filled spikelet number and grain weight per plant, particularly for inferior grains in Nagina 22. Grain quality parameters such as head rice recovery, high-density grains, and gelatinization temperature were maintained in Nagina 22. An increase in the rheological properties of rice flour starch in Nagina 22 under HNT indicated the stability of starch and its ability to reorganize during the cooling process of product formation. Thus, our study showed that sink adjustments between superior and inferior spikelets favored the growth of inferior spikelets, which helped to offset the reduction in grain weight under HNT in the tolerant genotype Nagina 22.