Recycling Design and Utilization of Agricultural Water Conservation Heritage Resources in the Early Period of Socialism in Chongqing

Chongqing has rich agricultural water resources in the early days of the founding of the People’s Republic of China. Through protective restoration and design, development and design utilization, a large-scale agricultural water conservancy network in which Chongqing integrates old and new water storage and irrigation is constructed. This will benefit Chongqing’s agriculture, rural areas, and farmers, empower rural areas, and coordinate the construction of ecological civilization

Confirmation and Fine Mapping of a Major QTL for Aflatoxin Resistance in Maize Using a Combination of Linkage and Association Mapping

Maize grain contamination with aflatoxin from Aspergillus flavus (A. flavus) is a serious health hazard to animals and humans. To map the quantitative trait loci (QTLs) associated with resistance to A. flavus, we employed a powerful approach that differs from previous methods in one important way: it combines the advantages of the genome-wide association analysis (GWAS) and traditional linkage mapping analysis. Linkage mapping was performed using 228 recombinant inbred lines (RILs), and a highly significant QTL that affected aflatoxin accumulation, qAA8, was mapped. This QTL spanned approximately 7 centi-Morgan (cM) on chromosome 8. The confidence interval was too large for positional cloning of the causal gene. To refine this QTL, GWAS was performed with 558,629 single nucleotide polymorphisms (SNPs) in an association population comprising 437 maize inbred lines. Twenty-five significantly associated SNPs were identified, most of which co-localised with qAA8 and explained 6.7% to 26.8% of the phenotypic variation observed. Based on the rapid linkage disequilibrium (LD) and the high density of SNPs in the association population, qAA8 was further localised to a smaller genomic region of approximately 1500 bp. A high-resolution map of the qAA8 region will be useful towards a marker-assisted selection (MAS) of A. flavus resistance and a characterisation of the causal gene

sj-docx-1-jtr-10.1177_00472875241245042 – Supplemental material for The Paradox of Positivity: How Overly Positive Responses by Hosts Can Backfire on Peer-to-Peer Rental Platforms

Supplemental material, sj-docx-1-jtr-10.1177_00472875241245042 for The Paradox of Positivity: How Overly Positive Responses by Hosts Can Backfire on Peer-to-Peer Rental Platforms by Sai Liang, Danmeng Wu, Ziru Li, Yang Yang, Hong Xu and Dexiang Yin in Journal of Travel Research</p

Genetic Mapping of the Leaf Number above the Primary Ear and Its Relationship with Plant Height and Flowering Time in Maize

The leaf number above the primary ear (LA) is a major contributing factor to plant architecture in maize. The yield of leafy maize, which has extra LA compared to normal maize, is higher than normal maize in some regions. One major concern is that increasing LA may be accompanied by increased plant height and/or flowering time. Using an F2:3 population comprising 192 families derived from a leafy maize line and a normal maize line, an association population comprising 437 inbred maize lines, and a pair of near-isogenic maize lines, we mapped the quantitative trait loci (QTL) associated with LA and assessed its genetic relationship with flowering time and plant height. Ten QTL with an additive and dominant effect, 18 pairs of interacting QTL in the F2:3 population and seventeen significant SNPs in the association population were detected for LA. Two major QTL, qLA3-4 and qLA7-1, were repeatedly detected and explained a large proportion of the phenotypic variation. The qLA3-4 was centered on lfy1, which is a dominant gene underlying extra leaves above the ear in leafy maize. Four LA QTL were found to overlap with flowering time and/or plant height, which suggested that these QTL might have a pleiotropic effect. The pleiotropy of the lfy1 locus on LA, flowering time and plant height were validated by near-isogenic line analysis. These results enhance our understanding of the genetic architecture affecting maize LA and the development of maize hybrids with increased LA

Ability to Remove Na+ and Retain K+ Correlates with Salt Tolerance in Two Maize Inbred Lines Seedlings

Maize is moderately sensitive to salt stress; therefore, soil salinity is a serious threat to its production worldwide. Here, excellent salt-tolerant maize inbred line TL1317 and extremely salt-sensitive maize inbred line SL1303 were screened to understand the maize response to salt stress and its tolerance mechanisms. Relative water content, membrane stability index, stomatal conductance, chlorophyll content, maximum photochemical efficiency, photochemical efficiency, shoot and root fresh/dry weight, and proline and water soluble sugar content analyses were used to identify that the physiological effects of osmotic stress of salt stress were obvious and manifested at about 3 days after salt stress in maize. Moreover, the ion concentration of two maize inbred lines revealed that the salt-tolerant maize inbred line could maintain low Na+ concentration by accumulating Na+ in old leaves and gradually shedding them to exclude excessive Na+. Furthermore, the K+ uptake and retention abilities of roots were important in maintaining K+ homeostasis for salt tolerance in maize. RNA-seq and qPCR results revealed some Na+/H+ antiporter genes and Ca2+ transport genes were up-regulated faster and higher in TL1317 than those in SL1303. Some K+ transport genes were down-regulated in SL1303 but up-regulated in TL1317. RNA-seq results, along with the phenotype and physiological results, suggested that the salt-tolerant maize inbred line TL1317 possesses more rapidly and effectively responses to remove toxic Na+ ions and maintain K+ under salt stress than the salt-sensitive maize inbred line SL1303. This response should facilitate cell homoeostasis under salt stress and result in salt tolerance in TL1317

Gibberellin Biosynthetic Deficiency Is Responsible for Maize Dominant Dwarf11 (<i>D11</i>) Mutant Phenotype: Physiological and Transcriptomic Evidence

<div><p>Dwarf stature is introduced to improve lodging resistance and harvest index in crop production. In many crops including maize, mining and application of novel dwarf genes are urgent to overcome genetic bottleneck and vulnerability during breeding improvement. Here we report the characterization and expression profiling analysis of a newly identified maize dwarf mutant <i>Dwarf11</i> (<i>D11</i>). The <i>D11</i> displays severely developmental abnormalities and is controlled by a dominant Mendelian factor. The <i>D11</i> seedlings responds to both GA₃ and paclobutrazol (PAC) application, suggesting that dwarf phenotype of <i>D11</i> is caused by GA biosynthesis instead of GA signaling deficiency. In contrast, two well-characterized maize dominant dwarf plants <i>D8</i> and <i>D9</i> are all insensitive to exogenous GA₃ stimulation. Additionally, sequence variation of <i>D8</i> and <i>D9</i> genes was not identified in the <i>D11</i> mutant. Microarray and qRT-PCR analysis results demonstrated that transcripts encoding GA biosynthetic and catabolic enzymes <i>ent</i>-kaurenoic acid oxidase (KAO), GA 20-oxidase (GA20ox), and GA 2-oxidase (GA2ox) are up-regulated in <i>D11</i>. Our results lay a foundation for the following <i>D11</i> gene cloning and functional characterization. Moreover, results presented here may aid in crops molecular improvement and breeding, especially breeding of crops with plant height ideotypes.</p></div

DEGs involved in GA biosynthesis and catabolism.

<p>(<b>A</b>) GA biosynthesis and catabolism pathways were briefly diagramed. Transcripts encoding maize GA biosynthetic and catabolic enzymes ZmKAO, ZmGA20ox1, and ZmGA2ox8 are up-regulated in <i>D11</i>. (<b>B</b>) Semi-qRT-PCR validation of elevated transcripts <i>ZmKAO</i> and <i>ZmGA20ox1</i>. The <i>18S rRNA</i> gene was used as an internal control.</p

Response of maize <i>D11</i> mutant to GA₃ and PAC application.

<p>(<b>A</b>) Seedlings of WT and <i>D11</i> when treated with a 10⁻⁴ M GA₃ solution. Bar  = 10 cm. (<b>B</b>) The second leaf sheath length of WT and <i>D11</i> (<i>n</i> = 35) when treated with a 10⁻⁴ M GA₃ solution. (<b>C</b>) Seedlings of WT and <i>D11</i> when treated with a 10⁻⁴ M PAC solution. Bar  = 10 cm. (<b>D</b>) Shoot length of WT and <i>D11</i> (<i>n</i> = 40) when treated with a 10⁻⁴ M PAC solution. In figures (B) and (D), data are mean ±SD. Double asterisks indicate significant difference at P≤0.01 level compared with untreated samples by Student's <i>t</i> test.</p