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Four sorghum [Sorghum bicolor (L.) Moench] seed parents, male sterile A and four male fertile B maintainer lines (KS148A [Reg. no. PL‐321, PI 701488], KS148B [Reg. no. PL‐322, PI 701489], KS149A [Reg. no. PL‐323, PI 701490], KS149B [Reg. no. PL‐324, PI 701491], KS150A [Reg. no. PL‐325, PI 701492], KS150B [Reg. no. PL‐326, PI 701493], KS151A [Reg. no. PL‐327, PI 701494], KS151B [Reg. no. PL‐328, PI 701495]), and six pollinator parents [KS152R (Reg. no. PL‐329, PI 701496), KS153R (Reg. no. PL‐330, PI 701497), KS154R (Reg. no. PL‐331, PI 701498), KS155R (Reg. no. PL‐332, PI 701499), KS156R (Reg. no. PL‐333, PI 701500), and KS157R (Reg. no. PL‐334, PI 701501) from the Kansas State University, Agricultural Research Center, Hays, KS, were approved for release by the Kansas State University in July 2021. These 10 lines were from different populations and were developed through recurrent selection (random mating) followed by pedigree and backcross breeding methods between the selected germplasms (PI 574562, PI 550610, PI 574599, PI 574560, PI 550607, and IS 1269C), adapted breeding lines and different genetic male sterile ms3 lines (KP 8B, N310B, B06‐41701‐167, B9614, BHF14, BH8606‐6) in different combinations. Parent lines KS148A&B, KS149A&B, KS152R, and KS153R are tolerant to chilling stress and KS150A&B, KS151A&B, KS154R, KS155R, KS156R, and KS157R are tolerant to drought stress and are recommended to develop hybrids respectively for early (end of April to first week of May) and regular (end of May to first week of June) planting for the central Great Plains. Preliminary screening of all 10 lines showed tolerance to nine postemergence herbicides. These 10 parent lines are early to medium maturity, three‐dwarf (dw1, Dw2, dw3, dw4) in height, photoperiod‐insensitive, and possess unique combinations of plant and seed color. All 10 parent lines are tannin free with acceptable grain quality, short peduncle length, compact or semi‐compact panicles, and combining ability for yield and standability. Core Ideas: We released first time, nontannin chilling tolerant sorghum parents with adaptable agronomic traits background.The released sorghum drought tolerant parent lines are recommended to develop hybrids for drylands.All 10 of the released parent lines showed tolerance to nine post‐emergence herbicides in our preliminary screening. [ABSTRACT FROM AUTHOR]

Pulsed amplitude modulation (PAM) chlorophyll a fluorescence provides information about photosynthetic energy transduction. When reliably measured, chlorophyll a fluorescence provides detailed information about critical in vivo photosynthetic processes. Such information has recently provided novel and critical insights into how the yield potential of crops can be improved and it is being used to understand remotely sensed fluorescence, which is termed solar‐induced fluorescence and will be solely measured by a satellite scheduled to be launched this year. While PAM chlorophyll a fluorometers measure fluorescence intensity per se, herein we articulate the axiomatic criteria by which instrumentally detected intensities can be assumed to assess fluorescence yield, a phenomenon quite different than fluorescence intensity and one that provides critical insight about how solar energy is variably partitioned into the biosphere. An integrated mathematical, phenomenological, and practical discussion of many useful chlorophyll a fluorescence parameters is presented. We draw attention to, and provide examples of, potential uncertainties that can result from incorrect methodological practices and potentially problematic instrumental design features. Fundamentals of fluorescence measurements are discussed, including the major assumptions underlying the signals and the methodological caveats about taking measurements during both dark‐ and light‐adapted conditions. Key fluorescence parameters are discussed in the context of recent applications under environmental stress. Nuanced information that can be gleaned from intra‐comparisons of fluorescence‐derived parameters and intercomparisons of fluorescence‐derived parameters with those based on other techniques is elucidated. [ABSTRACT FROM AUTHOR]

Leaf area index (LAI) is a widely used physiological parameter to quantify the vegetative canopy structure of crops. Over the years, several models to estimate LAI have been developed with various degrees of complexity and inherent shortcomings. The LAI simulation models proposed so far for sorghum [Sorghum bicolor (L.) Moench] either lack details of the leaf area dynamics of expanding leaves or demand exhaustive measurements. The objective of this study was to develop a simple quantitative model to predict the LAI of sorghum by introducing a new method for simulation of the leaf area of expanding leaves. The proposed model relates LAI to thermal time. It calculates LAI from an algorithm considering the total number of mature leaves, the area of mature leaves, the area of expanding leaves, and plant density. The performance of the model was tested using LAI data collected using a nondestructive method under field conditions. The slope of the regression of modeled LAI on observed LAI varied for photoperiod-sensitive and -insensitive genotypes in 2010. The coefficients of determination (R) between modeled and observed LAI were 0.96 in 2009 and 0.99 (photoperiod insensitive) and 0.95 (photoperiod sensitive) in 2010. The inclusion of expanding leaves in the model improved its accuracy. The model provides an accurate estimate of LAI at any given day of the vegetative growing season based only on thermal time and making use of default coefficients demonstrated in this research. [ABSTRACT FROM AUTHOR]

Increasing water and radiation use efficiencies (WUE and RUE, respectively) are critical to enhance crop production. Exploring genetic variability in WUE and RUE is necessary to improve these traits. The objectives of this research were to evaluate eight sorghum [Sorghum bicolor (L.) Moench] genotypes for biomass production, WUE, and RUE and to test whether the differences in WUE among sorghum genotypes were associated with increased biomass production or decreased water use under field conditions. The WUE was estimated as the slope of the regression of aboveground biomass on cumulative water use for specified sampling intervals. The RUE was estimated as the slope of the regression of aboveground biomass on cumulative intercepted photosynthetically active radiation (IPAR). Sorghum genotypes showed significant differences in biomass production, WUE, and RUE. The WUE varied from 3.39 ± 0.80 to 5.42 ± 0.80 g kg-1 in 2009 and from 4.04 ± 0.58 to 7.63 ± 0.58 g kg-1 in 2010. Similarly, RUE varied from 2.13 ± 0.33 to 3.53 ± 0.31 g MJ-1 IPAR in 2009 and from 2.08 ± 0.35 to 3.83 ± 0.33 g MJ-1 IPAR in 2010. Among the eight sorghum genotypes tested in this study, IS 27111 and IS 27150 had the largest biomass production, WUE, and RUE. The WUE was more strongly correlated to biomass production than to water use. This result implies that it is possible to improve WUE without compromising biomass production. The sorghum genotypes evaluated for biomass production, WUE, and RUE in this study offer useful plant materials for identifying the mechanisms causing differences in these traits. [ABSTRACT FROM AUTHOR]

Temperature controls many processes of NH3 volatilization. For example, urea hydrolysis is an enzymatically catalyzed reaction described by the Arrhenius equation. Diet crude protein (CP) controls NH3 emission by affecting N excretion. Our objectives were to use the Arrhenius equation to model NH3 emissions from beef cattle (Bos taurus) feedyards and test predictions against observed emissions. Per capita NH3 emission rate (PCER), air temperature (T), and CP were measured for 2 yr at two Texas Panhandle feedyards. Data were fitted to analogs of the Arrhenius equation: PCER = f(T) and PCER = f(T,CP). The models were applied at a third feedyard to predict NH3 emissions and compare predicted to measured emissions. Predicted mean NH3 emissions were within -9 and 2% of observed emissions for the f(T) and f(T,CP) models, respectively. Annual emission factors calculated from models underestimated annual NH3 emission by 11% [f(T) model] or overestimated emission by 8% [f(T,CP) model]. When T from a regional weather station and three classes of CP drove the models, the f(T) model overpredicted annual NH3 emission of the low CP class by 14% and underpredicted emissions of the optimum and high CP classes by 1 and 39%, respectively. The f(T,CP) model underpredicted NH3 emissions by 15, 4, and 23% for low, optimum, and high CP classes, respectively. Ammonia emission was successfully modeled using T only, but including CP improved predictions. The empirical f(T) and f(T,CP) models can successfully model NH3 emissions in the Texas Panhandle. Researchers are encouraged to test the models in other regions where high-quality NH3 emissions data are available. [ABSTRACT FROM AUTHOR]