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Copyright of Journal of Henan Agricultural Sciences is the property of Editorial Board of Journal of Henan Agricultural Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract Background The chlorophyll content (CC) is a key factor affecting maize photosynthetic efficiency and the final yield. However, its genetic basis remains unclear. The development of statistical methods has enabled researchers to design and apply various GWAS models, including MLM, MLMM, SUPER, FarmCPU, BLINK and 3VmrMLM. Comparative analysis of their results can lead to more effective mining of key genes. Results The heritability of CC was 0.86. Six statistical models (MLM, BLINK, MLMM, FarmCPU, SUPER, and 3VmrMLM) and 1.25 million SNPs were used for the GWAS. A total of 140 quantitative trait nucleotides (QTNs) were detected, with 3VmrMLM and MLM detecting the most (118) and fewest (3) QTNs, respectively. The QTNs were associated with 481 genes and explained 0.29-10.28% of the phenotypic variation. Additionally, 10 co-located QTNs were detected by at least two different models or methods, three co-located QTNs were identified in at least two different environments, and six co-located QTNs were detected by different models or methods in different environments. Moreover, 69 candidate genes within or near these stable QTNs were screened based on the B73 (RefGen_v2) genome. GRMZM2G110408 (ZmCCS3) was identified by multiple models and in multiple environments. The functional characterization of this gene indicated the encoded protein likely contributes to chlorophyll biosynthesis. In addition, the CC differed significantly between the haplotypes of the significant QTN in this gene, and CC was higher for haplotype 1. Conclusion This study’s results broaden our understanding of the genetic basis of CC, mining key genes related to CC and may be relevant for the ideotype-based breeding of new maize varieties with high photosynthetic efficiency.

Background: The chlorophyll content (CC) is a key factor affecting maize photosynthetic efficiency and the final yield. However, its genetic basis remains unclear. The development of statistical methods has enabled researchers to design and apply various GWAS models, including MLM, MLMM, SUPER, FarmCPU, BLINK and 3VmrMLM. Comparative analysis of their results can lead to more effective mining of key genes. Results: The heritability of CC was 0.86. Six statistical models (MLM, BLINK, MLMM, FarmCPU, SUPER, and 3VmrMLM) and 1.25 million SNPs were used for the GWAS. A total of 140 quantitative trait nucleotides (QTNs) were detected, with 3VmrMLM and MLM detecting the most (118) and fewest (3) QTNs, respectively. The QTNs were associated with 481 genes and explained 0.29-10.28% of the phenotypic variation. Additionally, 10 co-located QTNs were detected by at least two different models or methods, three co-located QTNs were identified in at least two different environments, and six co-located QTNs were detected by different models or methods in different environments. Moreover, 69 candidate genes within or near these stable QTNs were screened based on the B73 (RefGen_v2) genome. GRMZM2G110408 (ZmCCS3) was identified by multiple models and in multiple environments. The functional characterization of this gene indicated the encoded protein likely contributes to chlorophyll biosynthesis. In addition, the CC differed significantly between the haplotypes of the significant QTN in this gene, and CC was higher for haplotype 1. Conclusion: This study's results broaden our understanding of the genetic basis of CC, mining key genes related to CC and may be relevant for the ideotype-based breeding of new maize varieties with high photosynthetic efficiency. [ABSTRACT FROM AUTHOR]

This study aimed to provide a scientific basis for elucidating the mechanisms by which leaf traits influence the photosynthetic characteristics and breeding of cultivars with high light efficiency. The variation and correlation of the leaf structural, stomatal, and photosynthetic characteristics of 23 Vcmicia montana germplasms were explored using a homogeneous garden test combined with regression analysis, redundancy analysis, and principal component analysis. Results showed extremely significant differences in leaf structure among the different germplasms. There were extremely significant differences in net photosynthetic rate, significant differences in transpiration rate, and intercellular CO2 concentration but no significant differences in stomatal conductance and water use efficiency. Net photosynthetic rate was extremely significantly positively correlated with palisade sea ratio, tissue structure compactness, and stomatal density; significantly positively correlated with palisade tissue thickness and stomatal long axis; and extremely significantly negatively correlated with tissue porosity. The main leaf structures affecting photosynthetic physiology included lower epidermis thickness, palisade tissue thickness, palisade sea ratio, stomatal area, and spongy tissue thickness, which had different degrees of correlation with photosynthetic physiology. Principal component analysis showed that the cumulative contribution rate of the first two principal components reached 94.243%, and the transpiration rate and net photosynthetic rate were the main indicators reflecting the photosynthetic characteristics of the 23 V. montana germplasms, among which PJ, LN, NK-2, XS-1, and PZ showed higher photosynthetic efficiency than the other germplasms. A close relationship was found between the leaf structure and photosynthetic physiology of V. montana. The differences in leaf structure due to geographic climate among V. montana germplasms influence their photosynthetic physiology to adapt to environmental changes. [ABSTRACT FROM AUTHOR]

Copyright of Journal of South China Agricultural University is the property of Gai Kan Bian Wei Hui and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A field experiment for the AD268 with large leaf and dwarf structure and the XY335 with small leaf and high structure at three planting densities of low (3 plants·m-2), medium (6 plants·m-2) and high (9 plants·m-2) was conducted. This study integrated the vertical distribution of canopy photosynthetically active radiation (PAR), a 3D canopy model, and a canopy photosynthesis model to analyze responses of the extinction coefficients estimated by the logarithmic approach (klog) and the regression approach (knls) to cultivar and density and their differences, and to evaluate the effects on simulating canopy light utilization. The results showed that there was a difference between klog and knls, and this difference was more obvious for AD268 and aggravated with increasing density. The fitness based on knls for canopy light distribution (R2=0.86) was better than klog (R2=0.77). The daily CO2 assimilation, above-ground dry matter accumulation and radiation use efficiency of AD268 simulated by klog and knls did not differ significantly at low densities, but the difference became larger with increasing density. The critical densities at which the difference become larger were 0.7-2.5plants·m-2. [ABSTRACT FROM AUTHOR]

Rice (Oryza sativa L.) is an important food crop species in China. Cultivating high-yielding rice varieties that have a high photosynthetic efficiency is an important goal of rice breeding in China. In recent years, due to the continual innovation of molecular breeding methods, many excellent genes have been applied in rice breeding, which is highly important for increasing rice yields. In this paper, the hexokinase gene OsHXK1 was knocked out via the CRISPR/Cas9 gene-editing method in the indica rice varieties Huanghuazhan, Meixiangzhan, and Wushansimiao, and OsHXK1-CRISPR/Cas9 lines were obtained. According to the results of a phenotypic analysis and agronomic trait statistics, the OsHXK1-CRISPR/Cas9 plants presented increased light saturation points, stomatal conductance, light tolerance, photosynthetic products, and rice yields. Moreover, transcriptome analysis showed that the expression of photosynthesis-related genes significantly increased. Taken together, our results revealed that knocking out OsHXK1 via the CRISPR/Cas9 gene-editing method could effectively lead to the cultivation of high-photosynthetic efficiency and high-yielding rice varieties. They also revealed the important roles of OsHXK1 in the regulation of rice yield and photosynthesis.

Copyright of Acta Agronomica Sinica is the property of Crop Science Society of China and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Henan Agricultural Sciences is the property of Editorial Board of Journal of Henan Agricultural Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Chinese Journal of Oil Crop Sciences is the property of Oil Crops Research Institute of Chinese Academy of Agricultural Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The light response curve and CO2 response curve of 17 potato varieties (lines) at the full-bloom stage were measured by using the LI-6400XT (a portable photosynthetic apparatus), and photosynthetic parameters were calculated fitting with a rectangular Hyperbola model. There were significant differences among different varieties (lines) in photosynthetic traits. Using principal factor analysis method, six photosynthetic parameters which had a significant impact on photosynthetic type of potato were selected when the cumulative contribution of variance accounted for 86.58%, including maximum net photosynthetic rate (Amax), light compensation point (Ic), dark respiration rate (Rd), initial efficiency of carboxylation (CE), leaf transpiration rate (Tr), and stomatal conductance (Cond.). According to the cluster and discriminant analysis of the six photosynthetic characteristics, 17 varieties (lines) of potato were divided into four categories. After comprehensive evaluation of the traits, five high photosynthetic efficiency varieties (lines) which belong to D class were picked out. These varieties showed higher net photosynthetic rate, stronger shade tolerance, lower consumption, moderate transpiration rate, higher stomatal conductance and medium initial carboxylation efficiency. They were Hezuo 88, D520, Dongnong 1014III03, Qingshu 9, and 2010-11, which can be regarded as high photosynthetic efficiency breeding. [ABSTRACT FROM AUTHOR]

Rice (Oryza sativa L.) is an important food crop species in China. Cultivating high-yielding rice varieties that have a high photosynthetic efficiency is an important goal of rice breeding in China. In recent years, due to the continual innovation of molecular breeding methods, many excellent genes have been applied in rice breeding, which is highly important for increasing rice yields. In this paper, the hexokinase gene OsHXK1 was knocked out via the CRISPR/Cas9 gene-editing method in the indica rice varieties Huanghuazhan, Meixiangzhan, and Wushansimiao, and OsHXK1-CRISPR/Cas9 lines were obtained. According to the results of a phenotypic analysis and agronomic trait statistics, the OsHXK1-CRISPR/Cas9 plants presented increased light saturation points, stomatal conductance, light tolerance, photosynthetic products, and rice yields. Moreover, transcriptome analysis showed that the expression of photosynthesis-related genes significantly increased. Taken together, our results revealed that knocking out OsHXK1 via the CRISPR/Cas9 gene-editing method could effectively lead to the cultivation of high-photosynthetic efficiency and high-yielding rice varieties. They also revealed the important roles of OsHXK1 in the regulation of rice yield and photosynthesis. [ABSTRACT FROM AUTHOR]