Quantitative Trait Loci: Separating, Pyramiding, and Cloning

Xu, Yunbi

doi:10.1002/9780470650097.ch4

Cited by 37 publications

(35 citation statements)

References 177 publications

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“…QTL pyramiding is the process of assembling several QTLs from different loci for a specific trait to produce superior genotypes (Xu 1997). A similar way of improving chlorophyll fluorescence parameters, and therefore photosynthesis, by MAS under drought conditions has been discussed (Guo et al 2008).…”

Section: Discussionmentioning

confidence: 99%

Mapping quantitative trait loci associated with chlorophyll a fluorescence parameters in soybean (Glycine max (L.) Merr.)

Yin

Meng

Song

et al. 2010

Planta

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Chlorophyll a fluorescence parameters can provide qualitative and quantitative information about photosynthetic processes in chloroplasts. JIP-test and modulated fluorescence (MF) parameters are commonly used chlorophyll a fluorescence parameters. This study was conducted to identify quantitative trait loci (QTLs) associated with JIP-test parameters, MF parameters, and photosynthetic rate (P(N)), and to examine the relationships among them in soybean (Glycine max (L.) Merr.). Pot and field experiments were performed to evaluate 184 recombinant inbred lines (RILs) for five JIP-test parameters (ABS/RC, TR(O)/ABS, ET(O)/TR(O), RE(O)/ET(O), and PI(ABS)), four MF parameters (Fv/Fm, Fv'/Fm', PhiPSII, and qP), and P(N).Significant correlations were commonly observed among JIP-test parameters, MF parameters, and P(N). QTL mapping analysis identified 13, 9, and 4 QTLs for JIP-test parameters, MF parameters, and P(N), respectively, of which 13 were stable. Four major genomic regions were detected: LG A2 (19.81 cM) for JIP-test parameters, LG C1 (94.31 and 97.61 cM) for P(N) and MF parameters, LG M (100.51 cM) for JIP-test and MF parameters, and LG O (30.61-49.91 cM) for P(N), JIP-test, and MF parameters. These results indicate that chlorophyll fluorescence parameters, especially PHIPSII and qP, could play an important role in regulating P(N), and that JIP-test and MF parameters could be controlled by the same or different genes. The QTLs identified in this study will help in the understanding of the genetic basis of photosynthetic processes in plants. They will also contribute to the development of marker-assisted selection breeding programs for photosynthetic capacity in soybean.

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Section: Discussionmentioning

confidence: 99%

Mapping quantitative trait loci associated with chlorophyll a fluorescence parameters in soybean (Glycine max (L.) Merr.)

Yin

Meng

Song

et al. 2010

Planta

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“…Can breeders modulate RCA gene expression by design? The GmRCAa and GmRCAb eQTLs we identified make it possible to improve RCA gene expression, and ultimately RCA activity and seed yield, by marker-assisted breeding methods such as QTL pyramiding, which is a process of assembling several QTLs for a specific trait from different loci to produce superior genotypes (Xu, 1997). However, our study constitutes only first-order knowledge about the genetic determinism of RCA expression levels in soybean.…”

Section: Eqtl Analysis Provides New Insights Into the Modulation Of Rmentioning

confidence: 99%

Expression Quantitative Trait Loci Analysis of Two Genes Encoding Rubisco Activase in Soybean

et al. 2009

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Rubisco activase (RCA) catalyzes the activation of Rubisco in vivo and plays a crucial role in photosynthesis. However, until now, little was known about the molecular genetics of RCA in soybean (Glycine max), one of the most important legume crops. Here, we cloned and characterized two genes encoding the longer a-isoform and the shorter b-isoform of soybean RCA (GmRCAa and GmRCAb, respectively). The two corresponding cDNAs are divergent in both the translated and 3# untranslated regions. Analysis of genomic DNA sequences suggested that the corresponding mRNAs are transcripts of two different genes and not the products of a single alternatively splicing pre-mRNA. Two additional possible a-form RCA-encoding genes, GmRCA03 and GmRCA14, and one additional b-form RCA-encoding gene, GmRCA11, were also isolated. To examine the function and modulation of RCA genes in soybean, we determined the expression levels of GmRCAa and GmRCAb, Rubisco initial activity, photosynthetic rate, and seed yield in 184 soybean recombinant inbred lines. Correlation of gene expression levels with three other traits indicates that RCA genes could play an important role in regulating soybean photosynthetic capacity and seed yield. Expression quantitative trait loci mapping revealed four trans-expression quantitative trait loci for GmRCAa and GmRCAb. These results could provide a new approach for the modulation of RCA genes to improve photosynthetic rate and plant growth in soybean and other plants.

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“…Over the last ten years, quantitative genetics, through the detection of quantitative trait loci (QTL), has become an important approach for identifying key regulatory or structural genes involved in the expression of complex physiological and agronomic traits in an integrated manner and for the study of plant responses to environmental constraints [175]. When QTLs for agronomic and phenotypic traits are located on a genetic map, it is possible to look for their genetic significance by establishing the co-location of QTLs for physiological or biochemical traits with genes putatively involved in the control of the trait of interest (candidate genes).…”

Section: Deciphering the Genetic Basis Of Nitrogen Use Efficiency In mentioning

confidence: 99%

Improving Nitrogen Use Efficiency in Crops for Sustainable Agriculture

et al. 2011

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Abstract:In this review, we present the recent developments and future prospects of improving nitrogen use efficiency (NUE) in crops using various complementary approaches. These include conventional breeding and molecular genetics, in addition to alternative farming techniques based on no-till continuous cover cropping cultures and/or organic nitrogen (N) nutrition. Whatever the mode of N fertilization, an increased knowledge of the mechanisms controlling plant N economy is essential for improving NUE and for reducing excessive input of fertilizers, while maintaining an acceptable yield and sufficient profit margin for the farmers. Using plants grown under agronomic conditions, with different tillage conditions, in pure or associated cultures, at low and high N mineral fertilizer input, or using organic fertilization, it is now possible to develop further whole plant agronomic and physiological studies. These can be combined with gene, protein and metabolite profiling to build up a comprehensive picture depicting the different steps of N uptake, assimilation and recycling to produce either biomass in vegetative organs or proteins in storage organs. We provide a critical overview as to how our understanding of the agro-ecophysiological, physiological and molecular controls of N assimilation in crops, under varying environmental conditions, has been improved. We have used combined approaches, based on agronomic studies, whole plant physiology, quantitative genetics, forward and reverse genetics and the emerging systems biology. Long-term sustainability may require a gradual transition from synthetic N inputs to legume-based crop rotation, including continuous cover cropping systems, where these may be possible in certain areas of the world, depending on climatic conditions. Current knowledge and prospects for future agronomic development and application for breeding crops adapted to lower mineral fertilizer input and to alternative farming techniques are explored, whilst taking into account the constraints of both the current world economic situation and the environment.

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Quantitative Trait Loci: Separating, Pyramiding, and Cloning

Cited by 37 publications

References 177 publications

Mapping quantitative trait loci associated with chlorophyll a fluorescence parameters in soybean (Glycine max (L.) Merr.)

Mapping quantitative trait loci associated with chlorophyll a fluorescence parameters in soybean (Glycine max (L.) Merr.)

Expression Quantitative Trait Loci Analysis of Two Genes Encoding Rubisco Activase in Soybean

Improving Nitrogen Use Efficiency in Crops for Sustainable Agriculture

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