Cotton genotypic variation in the photosynthetic response to irradiance
TL;DR: The photosynthetic response of 8 cotton (Gossypium hirsutum L.) genotypes to changing irradiance was investigated under field conditions during the 1998 through 2000 growing seasons and demonstrated that the two okra leaf-type genotypes photosynthesized at a greater rate per unit leaf area than all of the six normal leaf- type genotypes.
Abstract: The photosynthetic response of 8 cotton (Gossypium hirsutum L) genotypes to changing irradiance was investigated under field conditions during the 1998 through 2000 growing seasons Equations developed to describe the response of net photosynthetic rate (PN) to photosynthetic photon flux density (PPFD) demonstrated that, across all irradiances, the two okra leaf-type genotypes photosynthesized at a greater rate per unit leaf area than all of the six normal leaf-type genotypes This superior photosynthetic performance of the okra leaf-type genotypes can be partially explained by their 13 % greater leaf chlorophyll content relative to that of the normal leaf-type genotypes The 37 % reduction in leaf size brought upon by the okra leaf trait may have concentrated the amount of photosynthetic machinery per unit leaf area Nevertheless, the lack of sufficient canopy leaf surface area suppressed the potential yield development that could accompany the higher PN per unit leaf area
Citations
More filters
TL;DR: Significant variation in photosynthesis and growth in 64 wheat cultivars was explained by differences in photosynthetic capacity, operation and CO2 diffusion.
Abstract: Increasing photosynthesis in wheat has been identified as an approach to enhance crop yield, with manipulation of key genes involved in electron transport and the Calvin cycle as one avenue currently being explored. However, natural variation in photosynthetic capacity is a currently unexploited genetic resource for potential crop improvement. Using gas-exchange analysis and protein analysis, the existing natural variation in photosynthetic capacity in a diverse panel of 64 elite wheat cultivars grown in the field was examined relative to growth traits, including biomass and harvest index. Significant variations in photosynthetic capacity, biomass, and yield were observed, although no consistent correlation was found between photosynthetic capacity of the flag leaf and grain yield when all cultivars were compared. The majority of the variation in photosynthesis could be explained by components related to maximum capacity and operational rates of CO2 assimilation, and to CO2 diffusion. Cluster analysis revealed that cultivars may have been bred unintentionally for desirable traits at the expense of photosynthetic capacity. These findings suggest that there is significant underutilized photosynthetic capacity among existing wheat varieties. Our observations are discussed in the context of exploiting existing natural variation in physiological processes for the improvement of photosynthesis in wheat.
203 citations
TL;DR: Investigation into natural genetic variation in photosynthesis will provide insights into the genetic regulation of this complex trait, which can be used to understand evolutionary processes that affect primary production, allow greater understanding of the geneticregulation of photosynthesis and ultimately increase the productivity of the authors' crops.
182 citations
TL;DR: The work on natural variation in A, the different factors determining A and their interaction in yield formation are reviewed, with a major focus on potential exploitation of various traits for crop improvement.
Abstract: Raising crop yield potential is a major goal to ensure food security for the growing global population. Photosynthesis is the primary determinant of crop productivity and any gain in photosynthetic CO2 assimilation per unit of leaf area (A) has the potential to increase yield. Significant intraspecific variation in A is known to exist in various autotrophic organs that represent an unexploited target for crop improvement. However, the large number of factors that influence photosynthetic rates often makes it difficult to measure or estimate A under dynamic field conditions (i.e. fluctuating light intensities or temperatures). This complexity often results in photosynthetic capacity, rather than realized photosynthetic rates being used to assess natural variation in photosynthesis. Here we review the work on natural variation in A, the different factors determining A and their interaction in yield formation. A series of drawbacks and perspectives are presented for the most common analyses generally used to estimate A. The different yield components and their determination based on different photosynthetic organs are discussed with a major focus on potential exploitation of various traits for crop improvement. To conclude, an example of different possibilities to increase yield in wheat through enhancing A is illustrated.
56 citations
Cites background from "Cotton genotypic variation in the p..."
...…in pho- tosynthetic capacity in different C3 crops (Rawson et al., 1983; Blum, 1990; Watanabe et al., 1994; Fischer et al., 1998; Herv e et al., 2001; Pettigrew, 2004; Flood et al., 2011; Gu et al., 2012; Lawson et al., 2012; Driever et al., 2014; Gaju et al., 2016; Carmo-Silva et al., 2017;…...
[...]
...…that breeding has unintentionally selected for higher A. Subsequent research focusing on intraspecific variation in major crops such as cotton (Petti- grew, 2004), canola (Pater et al., 2017), rice (Gu et al., 2012), sunflower (Herv e et al., 2001) and wheat (Reynolds et al., 2000; Sadras…...
[...]
...Subsequent research focusing on intraspecific variation in major crops such as cotton (Pettigrew, 2004), canola (Pater et al....
[...]
...An undervalued and currently unexploited opportunity to increase yield, not mutually exclusive of genetic engineering approaches, is the extensive natural variation in photosynthetic capacity in different C3 crops (Rawson et al., 1983; Blum, 1990; Watanabe et al., 1994; Fischer et al., 1998; Herv e et al., 2001; Pettigrew, 2004; Flood et al., 2011; Gu et al., 2012; Lawson et al., 2012; Driever et al., 2014; Gaju et al., 2016; Carmo-Silva et al., 2017; Qu et al., 2017; Pater et al., 2017; Faralli et al., 2019b)....
[...]
TL;DR: Knowing of variation in both genetic and environmental influences on photosynthesis offers hope of improved photosynthetic performance through either a concerted genetic selection or modified production systems that minimize exposure to some of the rate‐limiting environmental conditions.
Abstract: Photosynthesis is the basis of plant dry matter production and a major determination of yield in cotton (Gossypium hirsutum L) Much of the cotton yield increases in recent years can be attributed to the improved partitioning of dry matter into reproductive growth rather than vegetative growth However, this strategy can only be taken so far before the amount of photosynthesizing leaf area becomes the limiting factor Therefore, improved plant photosynthesis coupled with good dry matter partitioning could lead to additional yield improvements Research has identified both genetic and environmental variations in the rate of cotton photosynthesis Superior leaf photosynthetic performance has been exhibited by okra and super‐okra leaf types compared to the normal leaf types Photosynthetic variation has also been identified within the normal leaf type pool of germplasm However, geneticists have generally not targeted this trait for genetic improvement in cotton In addition, leaf tissue concentration of the three major plant nutrients (nitrogen, potassium, and phosphorus) need to be maintained at sufficient levels for optimum photosynthesis Under deficient soil fertility conditions, supplemental fertilization can increase overall growth due to both increased leaf area production and increased photosynthetic rate per unit leaf area Both excessive and deficient soil moisture conditions can depress the photosynthetic performance of the plant and its corresponding growth Similarly, an optimum temperature range exists, above and below which the photosynthesis is negatively impacted This knowledge of variation in both genetic and environmental influences on photosynthesis offers hope of improved photosynthetic performance through either a concerted genetic selection or modified production systems that minimize exposure to some of the rate‐limiting environmental conditions
44 citations
TL;DR: Data suggested that this procedure provides little potential in selecting plants for drought tolerance when plants are grown under field culture and few and inconsistent correlations were found among CF values and lint yield or fiber properties.
Abstract: Chlorophyll fluorescence (CF) is one tool used by researchers to quantify plant water status during periods of limited water availability. The research reported herein was designed to evaluate a CF-based protocol as a tool for use in cotton, Gossypium spp. breeding programs for the identification of drought tolerant genotypes. Twenty genotypes were selected to represent diverse and distinct US germplasm pools. Replicated tests were performed in Lubbock and College Station, TX in 2006 and 2007. Dryland and irrigated treatments, as main plots, were applied in a randomized complete block design, split to genotypes. CF measurements were taken at mid-bloom and late bloom growth stages. Source leaf tissue was harvested at predawn and subjected to high temperature incubation with CF measurements subsequently taken hourly for 5 h. Drought stressed plants had not mobilized their carbohydrate reserves from their source leaves overnight and thus maintained cell viability and therefore higher CF values throughout the incubation and measurement period with the opposite being true for non-stressed plants. Fiber lint yield and fiber properties were measured for comparison with the CF data. Genotype × treatment effects complicated the classification of genotypic response to drought. Few and inconsistent correlations were found among CF values and lint yield or fiber properties. Data suggested that this procedure provides little potential in selecting plants for drought tolerance when plants are grown under field culture.
33 citations
Cites background or methods from "Cotton genotypic variation in the p..."
...Six normal leaf and two okra leaf upland cotton, G. hirsutum, genotypes were tested under dryland and irrigated conditions by Pettigrew (2004b)....
[...]
...Fluorescence and lint yield correlations Lint yield is used commonly to compare cotton genotypes under drought stress conditions (Dumka et al. 2004; Pettigrew 2004b; Singh et al. 2006)....
[...]
...Higher photosynthetic rates per unit leaf area have been observed in okra leaf genotypes (Pettigrew 2004a)....
[...]
References
More filters
TL;DR: This assay is very reproducible and rapid with the dye binding process virtually complete in approximately 2 min with good color stability for 1 hr with little or no interference from cations such as sodium or potassium nor from carbohydrates such as sucrose.
225,085 citations
"Cotton genotypic variation in the p..." refers methods in this paper
...The soluble protein in the resulting supernatant was quantified by the method of Bradford (1976)....
[...]
TL;DR: To determine if differences in leaf CO-exchange rate (CER) existed among cotton genotypes, investigate physiological mechanisms for the gas exchange differences, and determine if gas exchange parameters were related to genotypic lint yield variability were determined.
Abstract: In trying to increase the yield of upland cotton (L.), breeders have indirectly selected more for increases in harvest index than in photosynthesis. Future cotton yield advances may need increases in both harvest index and photosynthesis. The objectives of this study were to determine if differences in leaf CO-exchange rate (CER) existed among cotton genotypes, investigate physiological mechanisms for the gas exchange differences, and determine if gas exchange parameters were related to genotypic lint yield variability. Field studies were conducted from 1990 to 1992 on 18 cotton genotypes. Leaf CER, chlorophyli.(Chl) concentration, soluble protein concentration, specific leaf weight (SLW), lint yield, and yield components were determined each year. In addition, Chl fluorescence measurements were made in 1992. The CER of the 18 genotypes significantly varied about 10% from a low of 26.0 μmol m s to a high of 28.8 ltmol m s. DES 119 and MD 51 ne had higher CER, whereas the CER of Dixie King and Stoneviile 508 were lower. The genotypes differed in leaf Chl and soluble protein concentration in both 1991 and 1992. The CER was positively correlated with leaf Chl concentration (= 0.768*) and SLW (= 0.568*) in 1991. No difference in the Fv/Fm parameter of Chi fluorescence was found among the genotypes in 1992. A significant positive association (= 0.205**) was found between lint yield and CER during the boll filling period in 1990 and 1991. CER was positively associated with fiber micronaire (= 0.772*) and fiber maturity (0.797*) in 1992. As some cotton breeders bred for higher yielding genotypes, they may have inadvertently selected for increased photosynthesis.
112 citations
TL;DR: The use of narrow-row culture for the okra-leaf type provides an opportunity for overcoming its low leaf area, increasing its insolation interception, and increasing its lint yield.
Abstract: Narrow row spacings in crops can potentially increase total seasonal light energy interception. Our objective was to determine the effects of a combination of row spacing with different genotypes on light interception and yield of upland cotton (Gossypium hirsutum L.). In 1989 and 1990, an okra-leaf genotype and its normal-leaf isoline were grown in the field, using 0.5-m (narrow) and 1.0-m (wide) row spacings in early and late plantings each year. The photosynthetic photon flux density (PPFD) intercepted by the canopy was determined weekly and insolation interception calculated. Aboveground dry matter accumulation and leaf area were determined at five intervals throughout the season. Open bolls were counted, harvested, and their lint yield determined. Narrow row spacing increased seasonal insolation interception in both leaf types. Narrow rows increased the yield of the okra leaf over that of wide rows in both plantings in 1989 and for the late planting in 1990. Yield of the normal leaf was reduced by narrow rows in one environment, but not significantly affected by row spacing in three other environments. For okra leaf planted early or late and for the normal leaf planted late, variation in lint yield was strongly correlated with total seasonal insolation intercepted. The yield increase of the okra leaf grown in narrow rows was a result of an increase in the number of mature fruit produced per unit ground area and not an increase in fruit size. Narrow rows increased the efficiency of PPFD interception by a given leaf area. The use of narrow-row culture for the okra-leaf type provides an opportunity for overcoming its low leaf area, increasing its insolation interception, and increasing its lint yield.
100 citations
"Cotton genotypic variation in the p..." refers background in this paper
...Nonetheless, the reduction in overall leaf area index and therefore canopy solar radiation interception (Heitholt et al. 1992) prevent these high photosynthesizing okra leaf-type cottons from having superior yield to their normal leaf-type counterparts....
[...]
TL;DR: Stomatal and nonstomatal CO 2 assimilation processes are important in limiting A of water stressed cotton, and intrinsic differences in these processes enable some cotton cultivars to better tolerate water stress.
Abstract: Water stress reduces net CO2 assimilation (A) and yield of cotton (Gossypium hisutum L.), hut our knowledge of the physiology of water stress on A and assimilation capacity is incomplete. Experiments were conducted in a rain shelter-lysimeter facility in 1990 and 1991 to determine if the yields of two short-season cotton cultivars with common ancestry, TAMCOT HQ95 (HQ95) and G&P74+ (GP74), resulted from intrinsic differences in A and assimilation capacity. Water stress was imposed by withholding 0, 50 or 75, and 100% of the depleted soil water after flowering. Results indicated that both stomatal and nonstomatal factors were important in controlling A. HQ95 had higher A and g than GP74 over leaf water potentials (ψ L ) ranging from - 1.0 to - 3.2 MPa. Nonstomatal limitations to A were more important than stomatal factors when ψ L was > -1.5 MPa. Stomatal factors limited A when ψ L was < -1.5 MPa for both cultivars. The initial slope (S i ) and the maximum A at high c i (A max ) declined with increasing water stress for both cultivars. The S, was greater for HQ95 than GP74 over the range in ψ L and suggest that HQ95 had higher ribulose-1,5-bisphosphate carboxylase-oxygenase activity than GP74. Increasing water stress reduced A max equally in both cultivars. This suggests that electron transport processes for ribulose-1,5- bisphosphate regeneration of the cultivars did not differ. Therefore, stomatal and nonstomatal CO 2 assimilation processes are important in limiting A of water stressed cotton. Intrinsic differences in these processes enable some cotton cultivars to better tolerate water stress.
82 citations
"Cotton genotypic variation in the p..." refers background in this paper
...While genotypic differences have been detected in cotton leaf photosynthesis (Pettigrew et al. 1993, Pettigrew and Meredith 1994, Faver et al. 1996) and in the photosynthetic response to changing CO2 concentrations (Pettigrew and Turley 1998), little evidence exists documenting differences among…...
[...]
TL;DR: Genotypic differences in CER are likely due to a greater concentration of photosynthetic apparatus per unit leaf area caused by leaf thickness differences, however the possibility of differences in the rate of dark respiration or photores piration cannot be discounted.
Abstract: Photosynthesis rate could be a selection criterion for plant breeders, especially if lines with superior photosynthesis could be identified and coupled with those lines with suitable partitioning of photosynthate between reproductive and vegetative growth. Establishing why certain lines may differ in photosynthetic rate could provide additional tools for selection. Photosynthesis and leaf anatomy of the youngest fully expanded leaf in field plots of the super okra, okra, and normal leaftype isolines of the cotton (Gossypium hirsutum L.) genotype ‘MD 65− 11’, which differ in leaf size and degree of Iobing, were compared with the normal leaf genotype ‘DPL 50’. Super okra and okra averaged 24 and 22% greater leaf CO₂-exchange rates (CER), respectively, than the normal leaf isoline in both 1989 and 1990. These differences were associated primarily with greater specific leaf weight (SLW) and leaf chlorophyll concentration of the super okra and okra leaf types. Water use efficiency [WUEg = CER/leaf stomatal conductance (gₛ)] was and 40% greater for super okra and okra, respectively, during 1990 compared to normal leaf. Leaves of the super okra and okra isolines were 42% thicker than normal leaf which contributed to this greater SLW. The relative tissue percentage of various cell types and mesophyil surface area per unit leaf volume did not differ among genotypes. Rubisco concentrations per unit stroma area were similar among chloroplasts of the different genotypes. Genotypic differences in CER are likely due to a greater concentration of photosynthetic apparatus per unit leaf area caused by leaf thickness differences, however the possibility of differences in the rate of dark respiration or photores piration cannot be discounted.
79 citations
"Cotton genotypic variation in the p..." refers background or result in this paper
...The higher leaf Chl content in okra leaftype line is similar to that previously reported for okra– normal leaf-type comparisons (Pettigrew et al. 1993)....
[...]
...The okra leaf-type lines in this study tended to have lower ALM than the normal leaf-type lines, in contrast to previous research that found okra leaf-type lines to have higher ALM (Pettigrew et al. 1993)....
[...]
...While genotypic differences have been detected in cotton leaf photosynthesis (Pettigrew et al. 1993, Pettigrew and Meredith 1994, Faver et al. 1996) and in the photosynthetic response to changing CO2 concentrations (Pettigrew and Turley 1998), little evidence exists documenting differences among…...
[...]
...In this prior research, thicker leaves for the okra-leaf-type line were associated with greater ALM, leaf Chl content, and leaf soluble protein content, indicative of an increased content of the photosynthetic apparatus per unit leaf area....
[...]
...Okra leaf-type genotypes in this study photosynthesized at higher rates under PPFD saturation than the normal leaf-type genotypes, similar to previous research (Pettigrew et al. 1993)....
[...]