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Gao Z.Q.,China National Rice Research Institute
Yi chuan = Hereditas / Zhongguo yi chuan xue hui bian ji | Year: 2011

Increase of crop production is the primary goal of crop breeding. Rice grain shape is a quantitative trait that is directly related to yield traits and has a close relationship with quality traits. The evaluation of grain shape is mainly grain length, grain width, grain thickness, length/width, and length/thickness. In recent years, the quantitative genetic research on rice grain shape has made a significant progress and a number of important genes associated with rice grain shape have been cloned. This paper reviews the classic genetic analysis on rice grain traits, QTL mapping, grain shape gene cloning and functional analysis, and their application in rice breeding for super high yield.

The present invention provides a soil heavy metal curing agent for controlling accumulation of heavy metals of crops and its preparation method. The curing agent is made from the following parts of raw materials by weight: 60140 parts of substance containing carbon-carbon double bond; 1400 parts of sulfo-compound by sulfur; 50500 parts of organic matter by 10% water content; 0400 parts of water; 0100 parts of an initiator; 0200 parts of a reducer; and 0200 parts of a strong base. The curing agent for heavy metals in the soil according to the present invention can reduce the cadmium, lead and mercury content in the soil and further greatly reduce the roots absorption of these heavy metals.

(Phys.org)—A team of researchers with the Chinese Academy of Sciences and the China National Rice Research Institute has successfully mapped the genomic regions associated with yield traits in several elite rice lines as part of a study to determine the genomic architecture of heterosis. In their paper published in the journal Nature, the team describes the laborious process they used and why they believe that their work could lead to finding a universally shared genomic region that contributes to heterosis. James Birchler with the University of Missouri offers an in depth look at the work done by the team in a News & Views piece in the same journal issue. Scientists have known for some time that when two plant species are bred together, the result is often a plant that is more fertile than either of its two parents—a phenomenon known as heterosis. Plant specialists have taken advantage of this feature to produce ever higher crop yields for a wide variety of crop plants, one of which is rice. Oddly, the genetic reasons for heterosis occurrence has never been found, though researchers have put a lot of effort into understanding it, as they believe it could lead to even higher yields or the introduction of other positive features. In this new effort, the researchers embarked on an ambitious project that they hoped would finally solve the mystery. The study consisted of collecting rice plant samples that represented 17 elite lines—they subsequently bred them to produce a first generation and then over 10,000 second-generations hybrids. The researchers studied each as they grew and produced rice and cataloged their features. Next, the team performed DNA sequencing on every one of the lines, which allowed them to compare genomic regions. As they did so, they wound up splitting the hybrids into three main groups based on the strategies that had been used to breed them. The researchers report that they were unable to identify the exact genomic architecture of heterosis, but they were able to isolate and map several genomic regions with the groups that could be associated with heteroic effects on rice grain yields. While this was not the outcome they had been hoping for, the work is still considered groundbreaking, Birchler notes, because it has shed a lot of light on the types of traits that are responsible for the phenomenon. More information: Xuehui Huang et al. Genomic architecture of heterosis for yield traits in rice, Nature (2016). DOI: 10.1038/nature19760 Abstract Increasing grain yield is a long-term goal in crop breeding to meet the demand for global food security. Heterosis, when a hybrid shows higher performance for a trait than both parents, offers an important strategy for crop breeding. To examine the genetic basis of heterosis for yield in rice, here we generate, sequence and record the phenotypes of 10,074 F2 lines from 17 representative hybrid rice crosses. We classify modern hybrid rice varieties into three groups, representing different hybrid breeding systems. Although we do not find any heterosis-associated loci shared across all lines, within each group, a small number of genomic loci from female parents explain a large proportion of the yield advantage of hybrids over their male parents. For some of these loci, we find support for partial dominance of heterozygous locus for yield-related traits and better-parent heterosis for overall performance when all of the grain-yield traits are considered together. These results inform on the genomic architecture of heterosis and rice hybrid breeding.

Xiang J.-J.,CAS Shanghai Institutes for Biological Sciences | Zhang G.-H.,China National Rice Research Institute | Qian Q.,China National Rice Research Institute | Xue H.-W.,CAS Shanghai Institutes for Biological Sciences
Plant Physiology | Year: 2012

Leaf rolling is an important agronomic trait in rice (Oryza sativa) breeding and moderate leaf rolling maintains the erectness of leaves and minimizes shadowing between leaves, leading to improved photosynthetic efficiency and grain yields. Although a few rolled-leaf mutants have been identified and some genes controlling leaf rolling have been isolated, the molecular mechanisms of leaf rolling still need to be elucidated. Here we report the isolation and characterization of SEMI-ROLLED LEAF1 (SRL1), a gene involved in the regulation of leaf rolling. Mutants srl1-1 (point mutation) and srl1-2 (transferred DNA insertion) exhibit adaxially rolled leaves due to the increased numbers of bulliform cells at the adaxial cell layers, which could be rescued by complementary expression of SRL1. SRL1 is expressed in various tissues and is expressed at low levels in bulliform cells. SRL1 protein is located at the plasma membrane and predicted to be a putative glycosylphosphatidylinositol-anchored protein. Moreover, analysis of the gene expression profile of cells that will become epidermal cells in wild type but probably bulliform cells in srl1-1 by laser-captured microdissection revealed that the expression of genes encoding vacuolar H+-ATPase (subunits A, B, C, and D) and H+-pyrophosphatase, which are increased during the formation of bulliform cells, were up-regulated in srl1-1. These results provide the transcript profile of rice leaf cells that will become bulliform cells and demonstrate that SRL1 regulates leaf rolling through inhibiting the formation of bulliform cells by negatively regulating the expression of genes encoding vacuolar H+-ATPase subunits and H+-pyrophosphatase, which will help to understand the mechanism regulating leaf rolling. © 2012 American Society of Plant Biologists.

Wu W.,China National Rice Research Institute | Cheng S.,China National Rice Research Institute
Field Crops Research | Year: 2014

Rice is one of the most important cereal crops, feeding more than 50% population of the world. To meet the demand of increasing population, rice production has to be improved continually. As a very important part of rice plant, root system plays multiple roles in rice growth: anchorage of the plant, acquisition of water and nutrient elements, and biosynthesis of amino acids and hormones, etc. Almost all of the hot spots about rice research are associated with rice root: drought tolerance, lodging resistance, and efficient use of nutrition, the goal is to increase the grain yield with desirable seed quality. Although the understanding about rice root has been expanded in the last decades, there remain much to be done about root morphology and physiology, especially in root genetics. Rice root research is an exciting and focusing field in recent years. More and more researches on rice root genetics have been made. There is a close relation between above ground traits and underground roots, providing an alternative approach for rice genetic improvement. A number of genes associated with root architecture and physiological functions have been identified, or cloned. It provides an opportunity to further improve rice based on molecular assisted selection. Root traits improvement should be taken into account in future breeding programs in rice. However, root research is still a consuming and difficult work, because it was largely influenced by the complex underground environment. This paper reviewed the progress in rice root genetic research, and discussed its prospects. © 2014 The Authors.

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