Seed Dormancy and Pre-Harvest Sprouting in Rice—An Updated Overview

Abstract

Pre-harvest sprouting is a critical phenomenon involving the germination of seeds in the mother plant before harvest under relative humid conditions and reduced dormancy. As it results in reduced grain yield and quality, it is a common problem for the farmers who have cultivated the rice and wheat across the globe. Crop yields need to be steadily increased to improve the people’s ability to adapt to risks as the world’s population grows and natural disasters become more frequent. To improve the quality of grain and to avoid pre-harvest sprouting, a clear understanding of the crops should be known with the use of molecular omics approaches. Meanwhile, pre-harvest sprouting is a complicated phenomenon, especially in rice, and physiological, hormonal, and genetic changes should be monitored, which can be modified by high-throughput metabolic engineering techniques. The integration of these data allows the creation of tailored breeding lines suitable for various demands and regions, and it is crucial for increasing the crop yields and economic benefits. In this review, we have provided an overview of seed dormancy and its regulation, the major causes of pre-harvest sprouting, and also unraveled the novel avenues to battle pre-harvest sprouting in cereals with special reference to rice using genomics and transcriptomic approaches.

QTL mapping and improvement of pre-harvest sprouting (PHS) resistance using japonica weedy rice

“…Preconscious germination before harvest causes deterioration in grain yield and quality. Thus, moderate dormancy is desirable for resistance to PHS in rice (Gu et al 2004;Sohn et al 2021). In this study, japonica-type Korean weedy rice, Wandoaengmi6, was used as a donor, with PHS resistance immediately after harvest, to improve the trait of japonica cultivars according to the increasing PHS damage caused by climate change in rice cultivation environments.…”

“…In addition, epistatic analysis was performed to detect interactions between QTL-QTL or QTL-background marker loci; however, no epistatic interactions were observed in this population. To date, several genetic studies based on molecular markers for the traits, such as PHS, seed dormancy, and low-temperature germination, were carried out and 185 QTLs have been identi ed and reported in rice 12 chromosomes, mainly concentrated in chromosome 1, 3, and 7 (Sohn et al 2021). Among these, there have been several meaningful reports related to PHS on chromosome 7, as with qPH7 in this study.…”

“…Several quantitative trait loci (QTLs) controlling seed dormancy have been identi ed in rice and other cereal crops, including the model plant Arabidopsis. In rice, 185 QTLs have been detected on all 12 chromosomes of the rice genome (Sohn et al 2021). Recently, ve QTLs were detected using a recombinant inbred line (RILs) derived from a japonica cross on chromosome 3, 4, and 11 (Cheon et al 2020).…”

Sdr4 dominates pre‐harvest sprouting and facilitates adaptation to local climatic condition in Asian cultivated rice

“…More than 140 quantitative trait loci (QTL)/genes have been shown to be associated with PHS or seed dormancy in rice (Sohn et al, 2021). However, only a few underlying genes have been cloned and functionally validated, including Sdr4 (Sugimoto et al, 2010), qSD7‐1/Rc (Gu et al, 2011), qSD1‐2/SD1 (Ye et al, 2015), PHS8 (Du et al, 2018), PHS9 (Xu et al, 2019), and Oryza sativa Viviparous1 ( OsVP1 ) (Chen et al, 2020; Wang et al, 2020), and our knowledge of PHS resistance is still limited.…”

QTL Mapping and Candidate Gene Analysis for Seed Germination Response to Low Temperature in Rice

“…In addition to that, abiotic stresses such as high/low temperature, drought, salinity, and submergence directly or indirectly influence the physiological status and molecular mechanisms of rice which badly affect yield [1][2][3][4]. The impact of temperature on seed germination is associated with the biosynthesis and signaling of ABA and GA. ABA and GA are the major endogenous regulators that antagonistically control seed dormancy and germination in several plant species [5]. A low temperature during seed development enhances the accumulation of ABA and reduces GA [6,7].…”