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In this work, rare-earth elements Eu and Y were added to La2Zr2O7 (LZ) as doping elements, and the ceramic coating of (La0.5Eu0.25Y0.25)2Zr2O7 (LEYZ) was prepared. The evolution of the sintering resistance, thermal shock resistance, and thermal insulation properties of the multi-element rare-earth co-doped modified coatings under long-term and high-temperature conditions was studied. The results showed that the sintering resistance of the doped coating was significantly improved, and the coating still does not fall off after 200 h at 1100 °C. The thermal shock life of the coating at 1000 °C is increased by 47% compared with that of the undoped modified LZ coating. The length of the vertical cracks in LEYZ ceramic layer is obviously shorter than that in LZ coating, which will be more beneficial to preventing the coating from peeling off. Compared with LZ coating, the insulation temperature of the LEYZ ceramic coating is increased by 24, 26 and 34% in the range of 900 ~ 1100 °C, respectively. The coating has the best thermal insulation effect, which is consistent with theoretical calculation results. The results demonstrate that the modified lanthanum zirconate coatings doped with Europium and Yttrium has great potential in high-temperature performance. [ABSTRACT FROM AUTHOR]

The key to food security is increasing rice yield. Therefore, we performed a genome-wide association study (GWAS) to analyse and identify the effects of plant height (PH), effective tiller number (ETN), heading date (HD) and grain weight per plant (GWPP) on rice yield using 1,220,522 single-nucleotide polymorphisms (SNPs) from 168 rice accessions. The PH, ETN, HD, and GWPP phenotypes of the 168 rice accessions were analysed in 2019, 2020 and 2021, and an abundance of phenotypic variation was found. One QTL for PH was detected on chromosome 4, one QTL for ETN on chromosome 11, two QTLs for GWPP on chromosome 2, and one QTL for HD on chromosome 5, all of which were detected in 3 years of the study period through a general linear model (GLM) and mixed linear model (MLM). We detected two QTLs related to the traits by using multi-trait GWAS. In addition, we identified four novel genes responsible for rice yield. Haplotype analysis indicated that LOC_Os02g07680 was highly associated with GWPP, LOC_Os11g18570 was highly associated with ETN, LOC_Os04g49210 was highly associated with HD, and LOC_Os05g34600 was highly associated with PH. The results provide important genetic information for PH, ETN, HD and GWPP studies, laying the foundation for increasing rice yield. [ABSTRACT FROM AUTHOR]

Key message: SYL3-k allele increases the outcrossing rate of male sterile line and the yield of hybrid F1 seeds via enhancement of endogenous GA4 content in Oryza sativa L. pistils. The change in style length might be an adaptation of rice cultivation from south to north in the northern hemisphere. The style length (SYL) in rice is one of the major factors influencing the stigma exertion, which affects the outcross rate of male sterile line and the yield of hybrid F1 seeds. However, the biological mechanisms underlying SYL elongation remain elusive. Here, we report a map-based cloning and characterisation of the allele qSYL3-k. The qSYL3-k allele encodes a MADS-box family transcription factor, and it is expressed in various rice organs. The qSYL3-k allele increases SYL via the elongation of cell length in the style, which is associated with a higher GA4 content in the pistil. The expression level of OsGA3ox2 in pistils with qSYL3-k alleles is significantly higher than that in pistils with qSYL3-n allele on the same genome background of Nipponbare. The yield of F1 seeds harvested from plants with 7001SSYL3−k alleles was 16% higher than that from plants with 7001SSYL3−n allele. The sequence data at the qSYL3 locus in 136 accessions showed that alleles containing the haplotypes qSYL3AA, qSYL3AG, and qSYL3GA increased SYL, whereas those containing the haplotype qSYL3GG decreased it. The frequency of the haplotype qSYL3GG increases gradually from the south to north in the northern hemisphere. These findings will facilitate improvement in SYL and yield of F1 seeds henceforward. [ABSTRACT FROM AUTHOR]

High sensitivity of rice coleoptile elongation length to exogenous gibberellin is a beneficial trait to utilize superior rice cultivars that could not be used originally under water direct-seeded conditions. In the present study, we mined favorable alleles for the trait by combining the phenotypic data of 358 rice accessions with their genotype data of 262 simple sequence repeat (SSR) markers via genome wide association mapping method. Totally, 17 SSR marker loci significantly associated with gibberellin sensitivity index (GSI) of coleoptile elongation length under 10 cm depth of water, were detected by general linear model and mixed linear model across two years, with percent phenotypic variation explained larger than 10%. Twenty nine favorable alleles for GSI on the 17 loci were discovered with phenotypic effect value (PEV) larger than 0.1 cm/cm and RM6869-110 bp showed the largest PEV (0.27 cm/cm). Based on PEV of marker-alleles having positive effects on GSI, seven parental combinations were predicted to improve GSI. In addition, 7 loci for GSI were co-located with loci associated with coleoptile elongation length per se, and one locus (RM1182 on chromosome 5) was co-located with that associated with coleoptile elongation length after gibberellin-soaked seed, under germination condition of 10 cm depth of water. These favorable allele(s) could be used to improve two target traits simultaneously. [ABSTRACT FROM AUTHOR]

Thousand grain weight (TGW) is an important determinant of rice yield, and correlates with grain size, plumpness and grain number per panicle. In rice, there are fewer association mapping studies relating grain weight traits using both SSR and SNP markers. In this study, in order to find robust SSR markers associated with TGW trait and mine elite accessions in rice, we investigated the TGW trait across six environments using a natural population consisted of 462 accessions, and then performed association mapping using both SSR and SNP markers. Using the six datasets from the six environments and their best linear unbiased estimator, we identified eight TGW associated SSR markers, with three environmentally stable and one newly found, on five chromosomes. The associated markers have genetic effect from 3.44% to 20.84%, and two of them carry stable elite allele with positive effect across different environments. Candidate interval association mapping using re-sequencing derived SNP/InDel markers further confirms the TGW-SSR association, and also suggests that 3 TGW-SSR associations were high confident in intervals of size from 176 to 603 kb. These results not only shed more lights on the genetics of TGW trait, but also suggest that the multi-allelic SSR markers should be used as an alternative power tool in gene or QTL mapping. [ABSTRACT FROM AUTHOR]

The outcrossing traits in rice affect the yield of hybrid rice seed production. In this study, 30 quantitative trait loci (QTLs) were detected in a natural population composed of 522 accessions by using a mixed linear model for the four outcrossing-related traits in 2017 and 2018. We detected 3, 4, 9 and 14 QTLs for flag leaf length (FLL), flag leaf width (FLW), flag leaf angle (FLA) and panicle neck length (PNL), respectively, among which 26 QTLs were novel. The favorable alleles and their carrier varieties were noticed with the largest phenotypic effect value. For FLL, marker allele RM6997-105 bp on chromosome 4 carried by Yue96 cultivar showed the highest phenotypic effect value (PEV), allele RM562-280 bp on chromosome 1 carried by Wanzhongqiu genotype for FLW, allele RM152-375 bp on chromosome 8 in typical carrier variety Zhongzuo93 for FLA and allele RM134-150 bp on chromosome 7 carried by Yue34 cultivar for PNL showed the highest PEVs. Additionally, nine QTLs were detected for the 4 traits with percentage of phenotypic variance explained (PVE) ranging from 16.24% (RM21) to 28.75% (RM5479) using a chromosome segment substitution line (CSSL) population. Among these detected QTLs, qFLL-12 and qFLW-12 showed 19.85% and 19.57% PVE, respectively. Four QTLs (qFLA-10, qFLA-11, qFLA-12.1, qFLA-12.2) detected for FLA showed PVEs ranging from 16.24% to 28.75%. For PNL, qPNL-7, qPNL-12.1, qPNL-12.2 were observed with PVEs of 20.14%, 17.39% and 28.36%, respectively. The favorable allele RM125-145 bp on chromosome 7 for PNL was detected in both the natural population and CSSL population and was carried by Yue38 accession and parent Xiushui79. The detected favorable alleles could be used to improve target traits. [ABSTRACT FROM AUTHOR]

The p K values of some phthalhydrazide derivatives were calculated using ab initio and two density functional methods to obtain information about their reaction conditions. The results showed that p K was influenced by structural modification as it varied between 0.47 and 6.99, and that p K was relatively less variable from 16.66 to 21.53. The high values of p K revealed that a strong alkaline solution was necessary for all chemiluminescent reactions of discussed phthalhydrazide derivatives. [ABSTRACT FROM AUTHOR]

Determination of the effective components in traditional Chinese medicine is one of the key steps for its identification. In this paper a novel and sensitive chemiluminescence (CL) method for the determination of rhein coupled with flow-injection analysis (FIA) is developed. It is based on the strong sensitizing effect on the weak CL reaction between luminol and ferricyanide in alkaline solution. Under optimal experimental conditions, the relative CL intensity is proportional to the concentration of rhein in the range of 7.0 × 10−12–7.0 × 10−10 mol L−1 and 1.0 × 10−9–4.0 × 10−5 mol L−1, the detection limit is 1.478 × 10−13 mol L−1, and the relative standard deviation (RSD) for 9 parallel measurements of 1.408 × 10−7 mol L−1 rhein is 3.4%. The method was successfully applied to the determination of rhein in pharmaceutical preparations. The possible mechanism of CL is also briefly discussed. [ABSTRACT FROM AUTHOR]

A capillary electrophoresis on-line inhibited luminol-K3Fe(CN)6 chemiluminescence method was employed for the determination of 2,3,5,4'-tetrahydroxystilbene-2-O-ß-D-glucoside (I) and baicalin (baicalein 7-O-glucuronide, II). In this system, luminol was added to running buffer solution and introduced at the head of the separation capillary, and K3Fe(CN)6 was introduced at the end of the capillary. The parameters affecting the separation process and CL detection were studied. Under the optimum conditions, the baseline separation of the two analytes was obtained within 4?min. The detection limits (S/N=3) for I and II were 3.0×10-6?M and 1.2×10-6?M, respectively. This proposed method was successfully applied to the determination of II in traditional Chinese medicines. [ABSTRACT FROM AUTHOR]

The acreage of submerged direct-sown cultivation of Oryza sativa is gradually increasing in China because of the constantly decreasing number of laborers in rural areas. Identifying favorable alleles for seedling anoxic tolerance (SAT) is necessary for improving cultivars suitable for submerged direct-sown rice cultivation. In this study, we used two populations to detect quantitative trait loci (QTLs) for SAT. In the natural population consisting of 542 accessions, seven simple sequence repeat marker loci associated with SAT were detected in both 2016 and 2017, with 22 favorable alleles. RM5340 on chromosome 2 and RM6811 on chromosome 6 were newly identified. Allele RM6811-160 bp had the largest phenotypic effect (1.09 cm/cm). Seventy-one accessions carried this allele. In the backcross inbred line population (115 lines) derived from Wuyunjing 7 hao/Ludao//Wuyunjing 7 hao, 8 QTLs for SAT were detected, with the phenotypic variance explained (PVE) ranging from 2.51 to 12.11%. The qCELpc2, qCELpc3, qCELpc5 and qCELpc11 loci were newly detected. The favorable alleles of loci qCELpc3, qCELpc5 and qCELpc11 were from Ludao. The locus qCELpc11 had the largest PVE of 10.39%, with a substitutive effect of 0.82 cm averaged over 2 years. By sequencing the gene locus OsBIERF, which was within a 15.50–16.08 Mb chromosome region harboring SAT-associated RM3600 on chromosome 9 and was detected in both populations, a single nucleotide polymorphism locus at the first exon was found between Wuyunjing 7 hao (T) and Ludao (C). The favorable alleles detected in this study could be used to improve SAT of rice cultivars. [ABSTRACT FROM AUTHOR]

Improving the combining ability for grain quality traits of the parents is the key factor to enhance averaged bulk grain quality of hybrid japonica rice. Eight quality traits including brown rice rate, milled rice rate (MRR), head rice rate (HRR), chalkiness degree (CD), percentage of chalky grain (PCG), alkali spreading value (ASV), gel consistency (GC) and amylose content (AC) of the bulked sample of rough rice harvested from the 81 F1 hybrid plants were investigated in 2014 and 2015. By combining the phenotypic data of general combining ability (GCA) for the quality traits with genotypic data of single nucleotide polymorphism (SNP) obtained by genotyping by sequencing method, CAScreen1.0 program compiled by MATLAB language was conducted to identify the elite SNP genotype associated with combining ability of quality traits in parents. Totally 35 elite SNP genotypes involving 22 genes (genotypes) were detected associated with GCA of seven quality traits (P < 0.05) in both 2014 and 2015. Seven and four SNPs were detected associated with combining ability for MRR and HRR, respectively. For PCG and CD, six and ten SNPs were detected associated with combining ability of parents, respectively. Six SNPs involving two genes were detected for combining ability of GC. Only two SNPs were detected which associated with combining ability for ASV. For combining ability of AC, six elite SNPs genotype were detected. Among them, elite SNP genotype of LOC_Os08g25220 (T/C) located on chromosome 8 could significantly reduce AC content in mixed rice samples of hybrid japonica rice. [ABSTRACT FROM AUTHOR]

Flag leaf angle (FLA) in rice (Oryza sativa L.) is one of the important traits affecting F1 seed production by mechanization. To elucidate the genetic mechanism of FLA and mine favorable marker alleles for F1 seed production in rice, we performed a genome-wide association study using phenotypic data over 2 years and genotypic data of 262 pairs of simple sequence repeat (SSR) markers collected from 441 rice accessions. We detected seven SSR marker loci associated with FLA and four loci were novel. The four newly found loci were RM6266 on chromosome 3, RM348 on chromosome 4, RM258 on chromosome 10 and RM7303 on chromosome 11. We found a total of 27 favorable alleles, of which four, i.e., RM348-130 bp, RM7303-90 bp, RM258-180 bp, and RM4835-230 bp, had phenotypic effects larger than 10°. Nine combinations, which increased FLA by 45.7°-94.7° through pyramiding the favorable alleles contained in seven typical accessions, were predicted. [ABSTRACT FROM AUTHOR]

We investigated the nuclear simple sequence repeat (SSR) genotypes of 532 rice (Oryza sativa L.) accessions collected from East and Southeast Asia and detected abundant genetic diversity within the population. We identified 6 subpopulations and found a tendency towards directional evolution in O. sativa from low to high latitudes, with levels of linkage disequilibrium (LD) in the 6 subpopulations ranging from 10 to 30 cM. We then investigated the phenotypic data for grain length, grain width, grain thickness and 1,000-grain weight over 4 years. Using a genome-wide association analysis, we identified 17 marker-trait associations involving 14 SSR markers on 12 chromosome arms, and 8 of the 17 associations were novel. The elite alleles were mined based on the phenotypic effects of the detected quantitative trait loci (QTLs). These elite alleles could be used to improve target traits through optimal cross designs, with the expected results obtained by pyramiding or substituting the elite alleles per QTL (independent of possible epistatic effects). Together, these results provide an in-depth understanding of the genetic diversity pattern among rice-grain traits across a broad geographic scale, which has potential use in future research work, including studies related to germplasm conservation and molecular breeding by design. [ABSTRACT FROM AUTHOR]

We investigated the nuclear simple sequence repeat (SSR) genotypes of 532 rice (Oryza sativa L.) accessions collected from East and Southeast Asia and detected abundant genetic diversity within the population. We identified 6 subpopulations and found a tendency towards directional evolution in O. sativa from low to high latitudes, with levels of linkage disequilibrium (LD) in the 6 subpopulations ranging from 10 to 30 cM. We then investigated the phenotypic data for grain length, grain width, grain thickness and 1,000-grain weight over 4 years. Using a genome-wide association analysis, we identified 17 marker-trait associations involving 14 SSR markers on 12 chromosome arms, and 8 of the 17 associations were novel. The elite alleles were mined based on the phenotypic effects of the detected quantitative trait loci (QTLs). These elite alleles could be used to improve target traits through optimal cross designs, with the expected results obtained by pyramiding or substituting the elite alleles per QTL (independent of possible epistatic effects). Together, these results provide an in-depth understanding of the genetic diversity pattern among rice-grain traits across a broad geographic scale, which has potential use in future research work, including studies related to germplasm conservation and molecular breeding by design. [ABSTRACT FROM AUTHOR]