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Larry C. Purcell - One of the best experts on this subject based on the ideXlab platform.
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genome wide association mapping of canopy Wilting in diverse soybean genotypes
Theoretical and Applied Genetics, 2017Co-Authors: Avjinder S Kaler, Andy C King, William T Schapaugh, Jeffery D Ray, Larry C. PurcellAbstract:Key message Genome-wide association analysis identified 61 SNP markers for canopy Wilting, which likely tagged 51 different loci. Based on the allelic effects of the significant SNPs, the slowest and fastest Wilting genotypes were identified.
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Mapping of quantitative trait loci for canopy-Wilting trait in soybean (Glycine max L. Merr)
Theoretical and Applied Genetics, 2012Co-Authors: Hussein Abdel-haleem, Larry C. Purcell, C. Andy King, Pengyin Chen, Thomas E Carter, Thomas R Sinclair, Landon L. Ries, William Schapaugh, H. Roger BoermaAbstract:Drought stress adversely affects [ Glycine max (L.) Merr] soybean at most developmental stages, which collectively results in yield reduction. Little information is available on relative contribution and chromosomal locations of quantitative trait loci (QTL) conditioning drought tolerance in soybean. A Japanese germplasm accession, PI 416937, was found to possess drought resistance. Under moisture-deficit conditions, PI 416937 wilted more slowly in the field than elite cultivars and has been used as a parent in breeding programs to improve soybean productivity. A recombinant inbred line (RIL) population was derived from a cross between PI 416937 and Benning, and the population was phenotyped for canopy Wilting under rain-fed field conditions in five distinct environments to identify the QTL associated with the canopy-Wilting trait. In a combined analysis over environments, seven QTL that explained 75 % of the variation in canopy-Wilting trait were identified on different chromosomes, implying the complexity of this trait. Five QTL inherited their positive alleles from PI 416937. Surprisingly, the other two QTL inherited their positive alleles from Benning. These putative QTL were co-localized with other QTL previously identified as related to plant abiotic stresses in soybean, suggesting that canopy-Wilting QTL may be associated with additional morpho-physiological traits in soybean. A locus on chromosome 12 (Gm12) from PI 416937 was detected in the combined analysis as well as in each individual environment, and explained 27 % of the variation in canopy-Wilting. QTL identified in PI 416937 could provide an efficient means to augment field-oriented development of drought-tolerant soybean cultivars.
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physiological traits contributing to differential canopy Wilting in soybean under drought
Crop Science, 2012Co-Authors: Landon Linn Ries, Larry C. Purcell, Thomas E Carter, Jeffery T Edwards, Andy C KingAbstract:ABSTRACTDelayed Wilting is observed in a few unusual soy-bean [ Glycine max (L.) Merr.] genotypes, but the reasons and importance of this trait for conferring agronomic drought tolerance are poorly under-stood. We hypothesized that soybean genotypes with delayed Wilting conserve soil moisture by restricting transpiration and that this would be refl ected in decreased radiation use effi ciency (RUE) and/or improved water use effi ciency (WUE). Water conserved when soil moisture was plentiful would be available later in the season when drought is usually more severe. Irrigated fi eld experiments in eight environments com-pared RUE of genotypes known to wilt differently during drought. In addition, we measured stoma-tal conductance, carbon isotope discrimination (CID), volumetric soil-moisture content, stomatal density, and canopy temperature depression. In six of the eight environments, slow-Wilting geno-types generally had lower RUE than fast-Wilting genotypes, which is consistent with our hypoth-esis. Three of four slow-Wilting genotypes had higher soil moisture immediately before irrigation than fast-Wilting genotypes, which is also consis-tent with the hypothesis. Genotypic differences in CID (a proxy for WUE) were present but were not consistently related with slow Wilting. No geno-typic differences were detected in stomatal con-ductance or canopy temperature. These results suggest that multiple mechanisms involving RUE and WUE could result in soil-water conservation in these diverse genotypes.L.L. Ries, Dep. of Agronomy and Plant Genetics, Univ. of Minne-sota, 1991 Upper Buford Cir., 411 Borlaug Hall, St. Paul, MN 55108; L.C. Purcell and C.A. King, Dep. of Crop, Soil, and Environmental Sciences, Univ. of Arkansas, 1366 W. Altheimer Dr., Fayetteville, AR 72704; T.E. Carter, Jr., USDA-ARS, 3127 Ligon St., Raleigh, NC 27607; J.T. Edwards, Dep. of Plant and Soil Science., Oklahoma State Univ., 368 Agricultural Hall, Stillwater, OK 74078. Received 20 May 2011. *Corresponding author (lpurcell@uark.edu).
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polygenic inheritance of canopy Wilting in soybean glycine max l merr
Theoretical and Applied Genetics, 2009Co-Authors: Dirk V Charlson, Andy C King, Clay Sneller, T. E. Carter, Sandeep Bhatnagar, Larry C. PurcellAbstract:As water demand for agriculture exceeds water availability, cropping systems need to become more efficient in water usage, such as deployment of cultivars that sustain yield under drought conditions. Soybean cultivars differ in how quickly they wilt during water-deficit stress, and this trait may lead to yield improvement during drought. The objective of this study was to determine the genetic mechanism of canopy Wilting in soybean using a mapping population of recombinant inbred lines (RILs) derived from a cross between KS4895 and Jackson. Canopy Wilting was rated in three environments using a rating scale of 0 (no Wilting) to 100 (severe Wilting and plant death). Transgressive segregation was observed for the RIL population with the parents expressing intermediate Wilting scores. Using multiple-loci analysis, four quantitative trait loci (QTLs) on molecular linkage groups (MLGs) A2, B2, D2, and F were detected (P ≤ 0.05), which collectively accounted for 47% of the phenotypic variation of genotypic means over all three environments. An analysis of the data by state revealed that 44% of the observed phenotypic variation in the Arkansas environments could be accounted for by these QTLs. Only the QTL on MLG F was detected at North Carolina where it accounted for 16% of the phenotypic variation. These results demonstrate that the genetic mechanism controlling canopy Wilting was polygenic and environmentally sensitive and provide a foundation for future research to examine the importance of canopy Wilting in drought tolerance of soybean.
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Differential Wilting among Soybean Genotypes in Response to Water Deficit
Crop Science, 2009Co-Authors: C. Andy King, Larry C. Purcell, Kristofor R. BryeAbstract:Genotypic differences for canopy Wilting have been reported for soybean [Glycine max (L.) Merr.], but no Wilting data have been published, and mechanisms for differences remain unresolved. In fi eld studies in 2002 and 2003, differences for Wilting among 19 genotypes were consistent across years. Plant introductions (PI 416937 and PI 471938) were among the slowest Wilting genotypes, and breeding lines (93705-34 and 93705-95) were among the fastest Wilting. Row spacing (18 vs. 80 cm wide) did not affect Wilting, indicating that lateral rooting did not contribute to genotypic differences. In a separate fi eld study, volumetric soil water content at 15- and 50-cm depths was generally greater for slow-Wilting PI 416937 than for fast-Wilting 93705-95. Wilting for both genotypes responded similarly to soil water content (r 2 = 0.63–0.74). In a growth chamber study, transpiration declined similarly for fast- and slow-Wilting genotypes in response to soil water defi cit. Wilting response to soil water was the same for slow-Wilting PI 416937 and fast-Wilting genotypes 93705-34 and A5959. Slow-Wilting 93705-36 began Wilting at a lower soil water content than did PI416937, 93705-34, and A5959, indicating that more than one mechanism may be responsible for slow Wilting.
Ariane Lentice De Paula - One of the best experts on this subject based on the ideXlab platform.
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comparing the classical permanent Wilting point concept of soil 15 000 hpa to biological Wilting of wheat and barley plants under contrasting soil textures
Agricultural Water Management, 2020Co-Authors: Lucia H. Wiecheteck, Neyde Fabíola Balarezo Giarola, Renato P. De Lima, Cássio Antonio Tormena, Lorena Chagas Torres, Ariane Lentice De PaulaAbstract:Abstract Recent studies have shown that the permanent Wilting point is influenced by soil properties and plant drought-tolerance mechanisms. This study was designed to evaluate the soil matric potential at which the biological Wilting point (BWPplant) of wheat and barley cultivars occurs compared to the classic concept of the permanent Wilting point at a matric potential of -15,000 hPa for soils (PWPsoil) with contrasting textures. The study was performed under greenhouse conditions with the experiment arranged in a completely randomised design in a double factorial scheme with three soil textures (sandy loam - SL, sandy clay loam - SCL and clay - C) and four plants (two crops (wheat and barley) and two cultivars for each crop). The 95 % confidence intervals were used to compare treatment means. The results revealed that BWPplant could occur at matric potential values > −15,000 hPa, i.e. wetter conditions than for the classical PWPsoil. Plants cultivated in clay soils withered at lower matric potentials than those in sandy soils, which could be related to a hydraulic cut-off that occurs at higher matric potentials in sandy soils. Barley plants were more sensitive to water deficits than wheat plants. The BWPplant for barley plants could occur at matric potentials values > −15,000 hPa, independently of soil texture, whereas wheat plants wilted at matric potentials > −15,000 hPa only in sandy soils (e.g. −1,637 to −2,417 hPa). Our results suggest that Wilting depends on soil texture, with an occurrence of Wilting at higher matric potentials (i.e. at wetter soil conditions) for sandy soils than for clay soils. Furthermore, plants/cultivars exhibit various tolerance mechanisms to drought, and wheat is able to take up water at considerably lower matric potentials (at dryer soil conditions) than barley. Thus, the Wilting matric potential threshold across various species and cultivars is not uniform.
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Comparing the classical permanent Wilting point concept of soil (−15,000 hPa) to biological Wilting of wheat and barley plants under contrasting soil textures
Agricultural Water Management, 2020Co-Authors: Lucia H. Wiecheteck, Neyde Fabíola Balarezo Giarola, Renato P. De Lima, Cássio Antonio Tormena, Lorena Chagas Torres, Ariane Lentice De PaulaAbstract:Abstract Recent studies have shown that the permanent Wilting point is influenced by soil properties and plant drought-tolerance mechanisms. This study was designed to evaluate the soil matric potential at which the biological Wilting point (BWPplant) of wheat and barley cultivars occurs compared to the classic concept of the permanent Wilting point at a matric potential of -15,000 hPa for soils (PWPsoil) with contrasting textures. The study was performed under greenhouse conditions with the experiment arranged in a completely randomised design in a double factorial scheme with three soil textures (sandy loam - SL, sandy clay loam - SCL and clay - C) and four plants (two crops (wheat and barley) and two cultivars for each crop). The 95 % confidence intervals were used to compare treatment means. The results revealed that BWPplant could occur at matric potential values > −15,000 hPa, i.e. wetter conditions than for the classical PWPsoil. Plants cultivated in clay soils withered at lower matric potentials than those in sandy soils, which could be related to a hydraulic cut-off that occurs at higher matric potentials in sandy soils. Barley plants were more sensitive to water deficits than wheat plants. The BWPplant for barley plants could occur at matric potentials values > −15,000 hPa, independently of soil texture, whereas wheat plants wilted at matric potentials > −15,000 hPa only in sandy soils (e.g. −1,637 to −2,417 hPa). Our results suggest that Wilting depends on soil texture, with an occurrence of Wilting at higher matric potentials (i.e. at wetter soil conditions) for sandy soils than for clay soils. Furthermore, plants/cultivars exhibit various tolerance mechanisms to drought, and wheat is able to take up water at considerably lower matric potentials (at dryer soil conditions) than barley. Thus, the Wilting matric potential threshold across various species and cultivars is not uniform.
Neyde Fabíola Balarezo Giarola - One of the best experts on this subject based on the ideXlab platform.
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Impacts of soil type and crop species on permanent Wilting of plants
Geoderma, 2021Co-Authors: Lorena Chagas Torres, Renato P. De Lima, Cássio Antonio Tormena, Thomas Keller, Herdjania Veras De Lima, Neyde Fabíola Balarezo GiarolaAbstract:Abstract The lack of a continuous network of water-filled pores necessary for the flow of water in the soil has been related to the Wilting of plants as well as to the limitations of soil sample equilibrium in pressure plates. The objectives of this study were: (i) to quantify deviations of the soil water content measured in pressure plates and dew point measurements at a matric potential of −15,000 hPa (commonly defined as the permanent Wilting point), (ii) to determine the soil matric potential at which the physiological Wilting of different plant species occurs in soil with contrasting texture, and (iii) to evaluate if the Wilting of plants occurs at the hydraulic cut-off in soil. An experiment was conducted to determine the soil matric potential at which Wilting of sunflower (Helianthus annuus L.), maize (Zea mays L.) and soybean (Glycine max L.) occurs in four soils with clay contents ranging from 7 to 57%. Soil water retention characteristics were determined by the pressure chamber and the dew point technique. Soil water retention data were fitted to empirical models for estimates of soil matric potential and water content at the hydraulic cut-off. The water contents at −15,000 hPa in samples equilibrated in pressure plates was similar to those obtained from the dew point method in our soils. Our results show that physiological Wilting of plants is both plant species and soil dependent. In soils with low clay contents, different plant species wilted at similar water contents. However, in the clayey soils, the different crops showed different abilities in the uptake of water from the soil, where soybean wilted at significantly lower water contents than the other two species. The values of matric potential at the permanent Wilting point found in our study were considerably lower than −15,000 hPa, suggesting that the commonly used definition of permanent Wilting point as water content at −15,000 hPa is incorrect.
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comparing the classical permanent Wilting point concept of soil 15 000 hpa to biological Wilting of wheat and barley plants under contrasting soil textures
Agricultural Water Management, 2020Co-Authors: Lucia H. Wiecheteck, Neyde Fabíola Balarezo Giarola, Renato P. De Lima, Cássio Antonio Tormena, Lorena Chagas Torres, Ariane Lentice De PaulaAbstract:Abstract Recent studies have shown that the permanent Wilting point is influenced by soil properties and plant drought-tolerance mechanisms. This study was designed to evaluate the soil matric potential at which the biological Wilting point (BWPplant) of wheat and barley cultivars occurs compared to the classic concept of the permanent Wilting point at a matric potential of -15,000 hPa for soils (PWPsoil) with contrasting textures. The study was performed under greenhouse conditions with the experiment arranged in a completely randomised design in a double factorial scheme with three soil textures (sandy loam - SL, sandy clay loam - SCL and clay - C) and four plants (two crops (wheat and barley) and two cultivars for each crop). The 95 % confidence intervals were used to compare treatment means. The results revealed that BWPplant could occur at matric potential values > −15,000 hPa, i.e. wetter conditions than for the classical PWPsoil. Plants cultivated in clay soils withered at lower matric potentials than those in sandy soils, which could be related to a hydraulic cut-off that occurs at higher matric potentials in sandy soils. Barley plants were more sensitive to water deficits than wheat plants. The BWPplant for barley plants could occur at matric potentials values > −15,000 hPa, independently of soil texture, whereas wheat plants wilted at matric potentials > −15,000 hPa only in sandy soils (e.g. −1,637 to −2,417 hPa). Our results suggest that Wilting depends on soil texture, with an occurrence of Wilting at higher matric potentials (i.e. at wetter soil conditions) for sandy soils than for clay soils. Furthermore, plants/cultivars exhibit various tolerance mechanisms to drought, and wheat is able to take up water at considerably lower matric potentials (at dryer soil conditions) than barley. Thus, the Wilting matric potential threshold across various species and cultivars is not uniform.
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Comparing the classical permanent Wilting point concept of soil (−15,000 hPa) to biological Wilting of wheat and barley plants under contrasting soil textures
Agricultural Water Management, 2020Co-Authors: Lucia H. Wiecheteck, Neyde Fabíola Balarezo Giarola, Renato P. De Lima, Cássio Antonio Tormena, Lorena Chagas Torres, Ariane Lentice De PaulaAbstract:Abstract Recent studies have shown that the permanent Wilting point is influenced by soil properties and plant drought-tolerance mechanisms. This study was designed to evaluate the soil matric potential at which the biological Wilting point (BWPplant) of wheat and barley cultivars occurs compared to the classic concept of the permanent Wilting point at a matric potential of -15,000 hPa for soils (PWPsoil) with contrasting textures. The study was performed under greenhouse conditions with the experiment arranged in a completely randomised design in a double factorial scheme with three soil textures (sandy loam - SL, sandy clay loam - SCL and clay - C) and four plants (two crops (wheat and barley) and two cultivars for each crop). The 95 % confidence intervals were used to compare treatment means. The results revealed that BWPplant could occur at matric potential values > −15,000 hPa, i.e. wetter conditions than for the classical PWPsoil. Plants cultivated in clay soils withered at lower matric potentials than those in sandy soils, which could be related to a hydraulic cut-off that occurs at higher matric potentials in sandy soils. Barley plants were more sensitive to water deficits than wheat plants. The BWPplant for barley plants could occur at matric potentials values > −15,000 hPa, independently of soil texture, whereas wheat plants wilted at matric potentials > −15,000 hPa only in sandy soils (e.g. −1,637 to −2,417 hPa). Our results suggest that Wilting depends on soil texture, with an occurrence of Wilting at higher matric potentials (i.e. at wetter soil conditions) for sandy soils than for clay soils. Furthermore, plants/cultivars exhibit various tolerance mechanisms to drought, and wheat is able to take up water at considerably lower matric potentials (at dryer soil conditions) than barley. Thus, the Wilting matric potential threshold across various species and cultivars is not uniform.
Lorena Chagas Torres - One of the best experts on this subject based on the ideXlab platform.
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Impacts of soil type and crop species on permanent Wilting of plants
Geoderma, 2021Co-Authors: Lorena Chagas Torres, Renato P. De Lima, Cássio Antonio Tormena, Thomas Keller, Herdjania Veras De Lima, Neyde Fabíola Balarezo GiarolaAbstract:Abstract The lack of a continuous network of water-filled pores necessary for the flow of water in the soil has been related to the Wilting of plants as well as to the limitations of soil sample equilibrium in pressure plates. The objectives of this study were: (i) to quantify deviations of the soil water content measured in pressure plates and dew point measurements at a matric potential of −15,000 hPa (commonly defined as the permanent Wilting point), (ii) to determine the soil matric potential at which the physiological Wilting of different plant species occurs in soil with contrasting texture, and (iii) to evaluate if the Wilting of plants occurs at the hydraulic cut-off in soil. An experiment was conducted to determine the soil matric potential at which Wilting of sunflower (Helianthus annuus L.), maize (Zea mays L.) and soybean (Glycine max L.) occurs in four soils with clay contents ranging from 7 to 57%. Soil water retention characteristics were determined by the pressure chamber and the dew point technique. Soil water retention data were fitted to empirical models for estimates of soil matric potential and water content at the hydraulic cut-off. The water contents at −15,000 hPa in samples equilibrated in pressure plates was similar to those obtained from the dew point method in our soils. Our results show that physiological Wilting of plants is both plant species and soil dependent. In soils with low clay contents, different plant species wilted at similar water contents. However, in the clayey soils, the different crops showed different abilities in the uptake of water from the soil, where soybean wilted at significantly lower water contents than the other two species. The values of matric potential at the permanent Wilting point found in our study were considerably lower than −15,000 hPa, suggesting that the commonly used definition of permanent Wilting point as water content at −15,000 hPa is incorrect.
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comparing the classical permanent Wilting point concept of soil 15 000 hpa to biological Wilting of wheat and barley plants under contrasting soil textures
Agricultural Water Management, 2020Co-Authors: Lucia H. Wiecheteck, Neyde Fabíola Balarezo Giarola, Renato P. De Lima, Cássio Antonio Tormena, Lorena Chagas Torres, Ariane Lentice De PaulaAbstract:Abstract Recent studies have shown that the permanent Wilting point is influenced by soil properties and plant drought-tolerance mechanisms. This study was designed to evaluate the soil matric potential at which the biological Wilting point (BWPplant) of wheat and barley cultivars occurs compared to the classic concept of the permanent Wilting point at a matric potential of -15,000 hPa for soils (PWPsoil) with contrasting textures. The study was performed under greenhouse conditions with the experiment arranged in a completely randomised design in a double factorial scheme with three soil textures (sandy loam - SL, sandy clay loam - SCL and clay - C) and four plants (two crops (wheat and barley) and two cultivars for each crop). The 95 % confidence intervals were used to compare treatment means. The results revealed that BWPplant could occur at matric potential values > −15,000 hPa, i.e. wetter conditions than for the classical PWPsoil. Plants cultivated in clay soils withered at lower matric potentials than those in sandy soils, which could be related to a hydraulic cut-off that occurs at higher matric potentials in sandy soils. Barley plants were more sensitive to water deficits than wheat plants. The BWPplant for barley plants could occur at matric potentials values > −15,000 hPa, independently of soil texture, whereas wheat plants wilted at matric potentials > −15,000 hPa only in sandy soils (e.g. −1,637 to −2,417 hPa). Our results suggest that Wilting depends on soil texture, with an occurrence of Wilting at higher matric potentials (i.e. at wetter soil conditions) for sandy soils than for clay soils. Furthermore, plants/cultivars exhibit various tolerance mechanisms to drought, and wheat is able to take up water at considerably lower matric potentials (at dryer soil conditions) than barley. Thus, the Wilting matric potential threshold across various species and cultivars is not uniform.
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Comparing the classical permanent Wilting point concept of soil (−15,000 hPa) to biological Wilting of wheat and barley plants under contrasting soil textures
Agricultural Water Management, 2020Co-Authors: Lucia H. Wiecheteck, Neyde Fabíola Balarezo Giarola, Renato P. De Lima, Cássio Antonio Tormena, Lorena Chagas Torres, Ariane Lentice De PaulaAbstract:Abstract Recent studies have shown that the permanent Wilting point is influenced by soil properties and plant drought-tolerance mechanisms. This study was designed to evaluate the soil matric potential at which the biological Wilting point (BWPplant) of wheat and barley cultivars occurs compared to the classic concept of the permanent Wilting point at a matric potential of -15,000 hPa for soils (PWPsoil) with contrasting textures. The study was performed under greenhouse conditions with the experiment arranged in a completely randomised design in a double factorial scheme with three soil textures (sandy loam - SL, sandy clay loam - SCL and clay - C) and four plants (two crops (wheat and barley) and two cultivars for each crop). The 95 % confidence intervals were used to compare treatment means. The results revealed that BWPplant could occur at matric potential values > −15,000 hPa, i.e. wetter conditions than for the classical PWPsoil. Plants cultivated in clay soils withered at lower matric potentials than those in sandy soils, which could be related to a hydraulic cut-off that occurs at higher matric potentials in sandy soils. Barley plants were more sensitive to water deficits than wheat plants. The BWPplant for barley plants could occur at matric potentials values > −15,000 hPa, independently of soil texture, whereas wheat plants wilted at matric potentials > −15,000 hPa only in sandy soils (e.g. −1,637 to −2,417 hPa). Our results suggest that Wilting depends on soil texture, with an occurrence of Wilting at higher matric potentials (i.e. at wetter soil conditions) for sandy soils than for clay soils. Furthermore, plants/cultivars exhibit various tolerance mechanisms to drought, and wheat is able to take up water at considerably lower matric potentials (at dryer soil conditions) than barley. Thus, the Wilting matric potential threshold across various species and cultivars is not uniform.
Thomas R Sinclair - One of the best experts on this subject based on the ideXlab platform.
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assessing water related plant traits to explain slow Wilting in soybean pi 471938
Journal of Crop Improvement, 2017Co-Authors: Laleh Bagherzadi, Thomas E Carter, Thomas R Sinclair, Maciej A Zwieniecki, Francesca Secchi, William A Hoffmann, Thomas W RuftyAbstract:ABSTRACTSoybean [Glycine max (L.) Merr.] genotype PI 471938 expresses a slow-Wilting phenotype in the field, and the progeny of this genotype have shown to have high yield under water deficit conditions. However, the physiological basis for the slow-Wilting trait in PI 471938 remains unclear, and failure to understand the causal mechanism may limit future breeding efforts. This study investigated three primary hypotheses for trait expression that could explain slow-Wilting trait in PI 471938: (1) a low osmotic potential in the leaves allowing greater water retention, (2) high elastic modulus of leaves resulting in delayed development of Wilting, and (3) high hydraulic conductance allowing rapid water redistribution in the plants. Experiments included three other soybean genotypes as references for the results obtained with PI 471938. Surprisingly, the results for PI 471938 did not prove to be unique as compared to the other three tested genotypes for any of the three hypotheses. These negative results ind...
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comparisons of the effects of elevated vapor pressure deficit on gene expression in leaves among two fast Wilting and a slow Wilting soybean
PLOS ONE, 2015Co-Authors: Mura Jyostna Devi, Thomas R Sinclair, Earl TaliercioAbstract:Limiting the transpiration rate (TR) of a plant under high vapor pressure deficit (VPD) has the potential to improve crop yield under drought conditions. The effects of elevated VPD on the expression of genes in the leaves of three soybean accessions, Plant Introduction (PI) 416937, PI 471938 and Hutcheson (PI 518664) were investigated because these accessions have contrasting responses to VPD changes. Hutcheson, a fast-Wilting soybean, and PI 471938, a slow-Wilting soybean, respond to increased VPD with a linear increase in TR. TR of the slow-Wilting PI 416937 is limited when VPD increases to greater than about 2 kPa. The objective of this study was to identify the response of the transcriptome of these accessions to elevated VPD under well-watered conditions and identify responses that are unique to the slow-Wilting accessions. Gene expression analysis in leaves of genotypes PI 471938 and Hutcheson showed that 22 and 1 genes, respectively, were differentially expressed under high VPD. In contrast, there were 944 genes differentially expressed in PI 416937 with the same increase in VPD. The increased alteration of the transcriptome of PI 416937 in response to elevated VPD clearly distinguished it from the other slow-Wilting PI 471938 and the fast-Wilting Hutcheson. The inventory and analysis of differentially expressed genes in PI 416937 in response to VPD is a foundation for further investigation to extend the current understanding of plant hydraulic conductivity in drought environments.
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Mapping of quantitative trait loci for canopy-Wilting trait in soybean (Glycine max L. Merr)
Theoretical and Applied Genetics, 2012Co-Authors: Hussein Abdel-haleem, Larry C. Purcell, C. Andy King, Pengyin Chen, Thomas E Carter, Thomas R Sinclair, Landon L. Ries, William Schapaugh, H. Roger BoermaAbstract:Drought stress adversely affects [ Glycine max (L.) Merr] soybean at most developmental stages, which collectively results in yield reduction. Little information is available on relative contribution and chromosomal locations of quantitative trait loci (QTL) conditioning drought tolerance in soybean. A Japanese germplasm accession, PI 416937, was found to possess drought resistance. Under moisture-deficit conditions, PI 416937 wilted more slowly in the field than elite cultivars and has been used as a parent in breeding programs to improve soybean productivity. A recombinant inbred line (RIL) population was derived from a cross between PI 416937 and Benning, and the population was phenotyped for canopy Wilting under rain-fed field conditions in five distinct environments to identify the QTL associated with the canopy-Wilting trait. In a combined analysis over environments, seven QTL that explained 75 % of the variation in canopy-Wilting trait were identified on different chromosomes, implying the complexity of this trait. Five QTL inherited their positive alleles from PI 416937. Surprisingly, the other two QTL inherited their positive alleles from Benning. These putative QTL were co-localized with other QTL previously identified as related to plant abiotic stresses in soybean, suggesting that canopy-Wilting QTL may be associated with additional morpho-physiological traits in soybean. A locus on chromosome 12 (Gm12) from PI 416937 was detected in the combined analysis as well as in each individual environment, and explained 27 % of the variation in canopy-Wilting. QTL identified in PI 416937 could provide an efficient means to augment field-oriented development of drought-tolerant soybean cultivars.
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transpiration responses to vapor pressure deficit in well watered slow Wilting and commercial soybean
Environmental and Experimental Botany, 2007Co-Authors: A L Fletcher, Thomas R Sinclair, Hartwell L AllenAbstract:Slow-Wilting has been observed in several soybean genotypes as a phenotypic response to drought stress. This trait has been proposed as useful in improving the yield of soybean under drought conditions, but the exact nature of the trait is unresolved. This research explored the hypothesis that slow-Wilting is an expression of soil water conservation that results from a plant-imposed limitation on maximum transpiration rate. Therefore, gas exchange by slow-Wilting and commercial genotypes was measured over a range of atmospheric vapor pressured deficit (VPD). Two experiments were undertaken to examine the response by whole plants and by plant canopies. The results showed that indeed the slow-Wilting genotypes reached a maximum transpiration rate at a VPD of about 2.0 kPa with little or no further increase in transpiration rate above this value as VPD was increased. In contrast, the commercial cultivars showed continued increases in transpiration rate as VPD was increased above 2.0 kPa. These results indicated that the slow-Wilting trait would be especially desirable in low humidity (high VPD) environments where water deficits commonly develop in the later part of the season. In these environments, restricted transpiration rate during the middle of the day with high vapor pressure deficit would result in water conservation allowing for both increased yield and water use efficiency.
