Language：English   Publishing type：Research paper (scientific journal)  

Reproductive isolation is an obstacle for plant breeding when a distant cross is demanded. It can be divided into two main types based on different growth stages: prezygotic isolation and postzygotic isolation. The hybrid weakness, which is a type of postzygotic isolation, can become a problem in crop breeding. In order to overcome reproductive isolation, it is necessary to elucidate its mechanism. In this study, genetic analysis for low temperature-dependent hybrid weakness was conducted in a rice F2 population derived from Taichung 65 (T65, Japonica) and Lijiangxintuanheigu (LTH, Japonica). The weak and severe weak plants in F2 showed shorter culm length, late heading, reduced panicle number, decreased grain numbers per panicle, and impaired root development in the field. Our result also showed that hybrid weakness was affected by temperature. It was observed that 24°C enhanced hybrid weakness, whereas 34°C showed recovery from hybrid weakness. In terms of the morphology of embryos, no difference was observed. Therefore, hybrid weakness affects postembryonic development and is independent of embryogenesis. The genotypes of 126 F2 plants were determined through genotyping-by-sequencing and a linkage map consisting of 862 single nucleotide polymorphism markers was obtained. Two major quantitative trait loci (QTLs) were detected on chromosomes 1 [hybrid weakness j 1 (hwj1)] and 11 [hybrid weakness j 2 (hwj2)]. Further genotyping indicated that the hybrid weakness was due to an incompatible interaction between the T65 allele of hwj1 and the LTH allele of hwj2. A large F2 populations consisting of 5,722 plants were used for fine mapping of hwj1 and hwj2. The two loci, hwj1 and hwj2, were mapped in regions of 65-kb on chromosome 1 and 145-kb on chromosome 11, respectively. For hwj1, the 65-kb region contained 11 predicted genes, while in the hwj2 region, 22 predicted genes were identified, two of which are disease resistance-related genes. The identified genes along these regions serve as preliminary information on the molecular networks associated with hybrid weakness in rice.

DOI： 10.3389/fpls.2022.908000

Web of Science

Scopus

PubMed

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Proceedings of the National Academy of Sciences  

The development of a plastic root system is essential for stable crop production under variable environments. Rice plants have two types of lateral roots (LRs): S-type (short and thin) and L-type (long, thick, and capable of further branching). LR types are determined at the primordium stage, with a larger primordium size in L-types than S-types. Despite the importance of LR types for rice adaptability to variable water conditions, molecular mechanisms underlying the primordium size control of LRs are unknown. Here, we show that two <italic>WUSCHEL-related homeobox</italic> (<italic>WOX</italic>) genes have opposing roles in controlling LR primordium (LRP) size in rice. Root tip excision on seminal roots induced L-type LR formation with wider primordia formed from an early developmental stage. <italic>QHB/OsWOX5</italic> was isolated as a causative gene of a mutant that is defective in S-type LR formation but produces more L-type LRs than wild-type (WT) plants following root tip excision. A transcriptome analysis revealed that <italic>OsWOX10</italic> is highly up-regulated in L-type LRPs. <italic>OsWOX10</italic> overexpression in LRPs increased the LR diameter in an expression-dependent manner. Conversely, the mutation in <italic>OsWOX10</italic> decreased the L-type LR diameter under mild drought conditions. The <italic>qhb</italic> mutants had higher <italic>OsWOX10</italic> expression than WT after root tip excision. A yeast one-hybrid assay revealed that the transcriptional repressive activity of QHB was lost in <italic>qhb</italic> mutants. An electrophoresis mobility shift assay revealed that <italic>OsWOX10</italic> is a potential target of QHB. These data suggest that QHB represses LR diameter increase, repressing <italic>OsWOX10</italic>. Our findings could help improve root system plasticity under variable environments.

DOI： 10.1073/pnas.2101846119

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Scopus

PubMed

Language：English   Publishing type：Research paper (scientific journal)  

A genetic resource for studying genetic architecture of agronomic traits and environmental adaptation is essential for crop improvements. Here, we report the development of a rice nested association mapping population (aus-NAM) using 7 aus varieties as diversity donors and T65 as the common parent. Aus-NAM showed broad phenotypic variations. To test whether aus-NAM was useful for quantitative trait loci (QTL) mapping, known flowering genes (Ehd1, Hd1, and Ghd7) in rice were characterized using single-family QTL mapping, joint QTL mapping, and the methods based on genome-wide association study (GWAS). Ehd1 was detected in all the seven families and all the methods. On the other hand, Hd1 and Ghd7 were detected in some families, and joint QTL mapping and GWAS-based methods resulted in weaker and uncertain peaks. Overall, the high allelic variations in aus-NAM provide a valuable genetic resource for the rice community.

DOI： 10.3390/plants10061255

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Scopus

PubMed

Language：English   Publishing type：Research paper (scientific journal)   Publisher：MDPI AG  

The era of the green revolution has significantly improved rice yield productivity. However, with the growing population and decreasing arable land, rice scientists must find new ways to improve rice productivity. Although hundreds of rice yield-related QTLs were already mapped and some of them were cloned, only a few were utilized for actual systematic introgression breeding programs. In this study, the major yield QTLs Grain Number 1a (Gn1a) and Wealthy Farmer’s Panicle (WFP) were introgressed and stacked in selected NERICA cultivars by marker-assisted backcross breeding (MABB). The DNA markers RM3360, RM3452, and RM5493 were used for foreground selection. At BC3F4 and BC3F5 generation, a combination of marker-assisted selection and phenotypic evaluation were carried out to select lines with target alleles and traits. Further, genotyping-by-sequencing (GBS) was conducted to validate the introgression and determine the recurrent parent genome recovery (RPGR) of the selected lines. The Gn1a and/or WFP introgression lines showed significantly higher numbers of spikelets per panicle and primary branching compared to the recurrent parents. In addition, lines with Gn1a and/or WFP alleles were comparatively similar to the recurrent parents (RP) in most yield-related traits. This study demonstrates the success of utilizing yield QTLs and marker-assisted selection to develop and improve rice cultivars.

DOI： 10.3390/plants10050844

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Scopus

PubMed

DOI： 10.​1016/​j.​plantsci.​2021.​110861

Authorship：Lead author   Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Japanese Society for Root Research  

<p>The radial oxygen loss (ROL) barrier formed on the outer cell layers of roots of rice (<i>Oryza sativa</i>) contributes to efficient oxygen transfer through the aerenchyma from the aerial parts to the root apex. It is hypothesized that suberin accumulation in the exodermis contributes to an apoplastic barrier and plays a vital role in ROL barrier formation. A previous study reported that some genes encoding cytochrome P450 family 86 (<i>CYP86</i>) and glycerol-3-phosphate acyltransferase (<i>GPAT</i>) might be involved in suberin biosynthesis during ROL barrier development of rice roots. However, how these genes are expressed and their contribution to the sequential development of suberin accumulation in rice roots remains unclear. In this study, four <i>CYP86</i> and five <i>GPAT</i> genes of rice were identified as candidate genes involved in suberin biosynthesis in roots using sequence homology alignment with <i>Arabidopsis</i> suberin and cutin biosynthesis genes. Gene expression analyses revealed that expression of the candidate genes was induced at the region where suberin biosynthesis occurred under stagnant deoxygenated conditions. These genes showed two types of spatiotemporal expression patterns, at the regions of 5–25 mm and 25–35 mm from the root apex. Tissue-specific expression analyses using laser microdissection and histochemical GUS staining revealed that candidate gene expression was similar in the cell layer of the root exodermis. These results suggest that the selected <i>CYP86</i> and <i>GPAT</i> genes are involved in suberin biosynthesis in the exodermis, and that suberin biosynthesis in the root may be controlled by the spatiotemporal expression of two groups of genes.</p>

DOI： 10.3117/plantroot.15.19

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Scopus

CiNii Research

Language：English   Publishing type：Research paper (scientific journal)  

<p>Problems with carbon assimilate translocation from source organs to sink (grains) during ripening cause yield losses in rice (<i>Oryza sativa</i> L.), especially in high-sink-capacity varieties. We conducted a genetic analysis of traits related to such translocation by using recombinant inbred lines. Shoot weight (SW) of T65, a <i>japonica</i> parent, was retained from heading to late maturity, whereas that of DV85, an <i>aus</i> parent, was greater than that of T65 at 5 days after heading (DAH) and then decreased until 20 DAH. This difference was observed clearly under standard-fertilizer but not low-fertilizer conditions. Non-structural carbohydrate (NSC) contents in the parents showed a tendency similar to that for SW. QTL analysis revealed pleiotropic QTLs on chromosomes 5 and 10, probably by associations with heading date QTLs. A QTL associated with harvest index and NSC at 5 DAH was detected on chromosome 1. By considering the temporal changes of the traits, we found a QTL for decrease in SW on chromosome 11; the DV85 allele of this QTL facilitated assimilate translocation and suppressed biomass growth. A suggestive QTL for NSC decrease was located on chromosome 2. These QTLs could represent potential targets for controlling carbon assimilate translocation in breeding programs.</p>

DOI： 10.1270/jsbbs.18203

Web of Science

Language：English   Publishing type：Research paper (scientific journal)   Publisher：The Japan Society of Mechanical Engineers  

The agriculture farmer income strongly depends on the weather conditions. Therefore, the income risk evaluation is very important for sustainable development of agricultural business. The aim of this study is to evaluate the income risk in the rice cultivation farmer. The income, which is defined as the product of the yield and the quality, is predicted by using Deep Neural Network. Then, the value at risk (VaR) in the income is evaluated by Monte Carlo simulation. The result is compared with the value at the real data.

DOI： 10.1299/jsmedsd.2018.28.2415

CiNii Research

Language：English   Publishing type：Research paper (scientific journal)   Publisher：The Japan Society of Mechanical Engineers  

The aim of this study is to predict the heading day of rice by using machine learning. The heading day denotes the blooming day in the rice cultivation, which is one of the important days in the rice cultivation stage. The number of days from the planting day to the heading day is taken as the objective variable. The cultivation variables such as the weather data, the position of the field and so on are taken as the explanatory variables. The prediction model is defined by using Xgboost algorithm. The prediction model showed that the average error is 3.19 days.

DOI： 10.1299/jsmedsd.2018.28.2412

CiNii Research

Language：English   Publishing type：Research paper (scientific journal)   Publisher：The Japan Society of Mechanical Engineers  

The schedule prediction in the rice cultivation is very important for controlling the cultivation process and then, for enhancing the farmer's income. The aim of this study is to predict the planting and the reaping days in the rice cultivation from the weather data by using the multiple linear regression analysis. The yield and the quality of the rice cultivation are also predicted from the weather data. The rice cultivation farmer's income is maximized by changing the heading and the reaping days in the rice cultivation. The algorithms are applied for Koshihikari and Aichinokaori in Aichi Prefecture in order to discuss the effectiveness of the present algorithms.

DOI： 10.1299/jsmedsd.2018.28.2414

CiNii Research

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1111/ppl.12707

PubMed

Language：English   Publishing type：Research paper (scientific journal)   Publisher：The Japan Society of Mechanical Engineers  

The aim of this study is to design the cultivation environment scenario in the rice plant cultivation by using data mining technique and optimization algorithm. The use of the multi-layer neural network model predicts the yield and the quality in the rice cultivation. As the objective function, the income is defined as the product of the yield and the quality. The scenario of the daily average temperature is changed in order to maximize the objective function. The result shows that the daily temperature in Nagoya is too high for the rice Oryza sativa 'Koshihikari'.

DOI： 10.1299/jsmedsd.2018.28.2413

CiNii Research

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1111/pce.12849

Web of Science

PubMed

Language：English   Publishing type：Research paper (scientific journal)   Publisher：The Japan Society of Mechanical Engineers  

The aim of this study is to design the cultivation environment scenario in the rice plant cultivation. The use of the neural network determines the prediction model which predicts the yield and the quality of the rice from the environmental scenario. The objective function, which is defined from the yield and the quality, is maximized by changing the scenario of the daily average temperature. The result shows that the temperature before the heading date in Nagoya is too high for the rice Oryza sativa &rsquo;Koshihikari&rsquo;.

DOI： 10.1299/jsmecmd.2017.30.018

CiNii Research

Language：English   Publishing type：Research paper (scientific journal)   Publisher：一般社団法人 人工知能学会  

<p>本研究は、手軽な農業ITとして普及が期待されるオンサイト圃場情報を利用することで、イネの収量と品質の両立を前提とした栽培管理を支援することを目的とします。本発表ではこれまでに記録された日本各地のイネ栽培レコードをどの様に用いるか、その手法について検討を行い、農業現場において重要なイネの出穂予測精度の向上に繋がるかどうか検証を行います。</p>

DOI： 10.11517/pjsai.JSAI2017.0_2E4OS36b2

CiNii Research

Language：English   Publishing type：Research paper (scientific journal)   Publisher：CROP SCIENCE SOCIETY OF JAPAN  

DOI： 10.14829/jcsproc.241.0_26

CiNii Research

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1111/tpj.12614

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.plantsci.2013.01.003

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.3389/fpls.2013.00178

Language：English   Publishing type：Research paper (scientific journal)  

PubMed

Language：English   Publishing type：Research paper (scientific journal)  

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：東京 : 日本生化学会  

CiNii Research

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1186/1939-8433-5-2

Language：Japanese   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

CiNii Books

CiNii Research

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1007/s12033-010-9349-3

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1007/s11103-007-9133-3

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.plaphy.2010.01.024

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1007/s11103-007-9133-3

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1007/s10529-007-9396-4

Language：Chinese   Publishing type：Research paper (scientific journal)  

Language：Chinese   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper, summary (national, other academic conference)   Publisher：一般社団法人 日本機械学会  

DOI： 10.1299/jsmedsd.2018.28.2414

Language：Japanese  

J-GLOBAL

Language：Japanese   Publishing type：Rapid communication, short report, research note, etc. (scientific journal)  

J-GLOBAL

Language：Japanese  

J-GLOBAL

Language：Japanese  

J-GLOBAL

Language：English   Publishing type：Research paper, summary (national, other academic conference)   Publisher：一般社団法人 日本機械学会  

DOI： 10.1299/jsmecmd.2017.30.018

Language：Japanese  

J-GLOBAL

Language：Japanese  

J-GLOBAL

Language：Japanese  

J-GLOBAL

Language：Japanese   Publishing type：Rapid communication, short report, research note, etc. (scientific journal)  

J-GLOBAL

Language：Japanese   Publishing type：Rapid communication, short report, research note, etc. (scientific journal)   Publisher：一般社団法人 日本土壌肥料学会  

CiNii Books

Language：Japanese   Publishing type：Rapid communication, short report, research note, etc. (scientific journal)  

Language：English   Publishing type：Rapid communication, short report, research note, etc. (scientific journal)  

Language：Japanese   Publishing type：Article, review, commentary, editorial, etc. (scientific journal)  

J-GLOBAL

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Language：Japanese   Presentation type：Oral presentation (general)  

Country：Japan  

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Country：Japan  

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Event date： 2022.12

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Event date： 2022.12

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Country：Japan  

Event date： 2022.12

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Country：Japan  

Event date： 2022.12

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Event date： 2022.9

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Event date： 2022.9

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Country：Japan  

Event date： 2022.9

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Country：Japan  

Event date： 2022.3

Language：Japanese   Presentation type：Oral presentation (general)  

Country：Japan