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125 result(s) for "leaf area duration"
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Soybean Yield Formation Physiology – A Foundation for Precision Breeding Based Improvement
The continued improvement of crop yield is a fundamental driver in agriculture and is the goal of both plant breeders and researchers. Plant breeders have been remarkably successful in improving crop yield, as demonstrated by the continued release of varieties with improved yield potential. This has largely been accomplished through performance-based selection, without specific knowledge of the molecular mechanisms underpinning these improvements. Insight into molecular mechanisms has been provided by plant molecular, genetic, and biochemical research through elucidation of the function of genes and pathways that underlie many of the physiological processes that contribute to yield potential. Despite this knowledge, the impact of most genes and pathways on yield components have not been tested in key crops or in a field environment for yield assessment. This gap is difficult to bridge, but field-based physiological knowledge offers a starting point for leveraging molecular targets to successfully apply precision breeding technologies such as genome editing. A better understanding of both the molecular mechanisms underlying crop yield physiology and yield limiting processes under field conditions is essential for elucidating which combinations of favorable alleles are required for yield improvement. Consequently, one goal in plant biology should be to more fully integrate crop physiology, breeding, genetics, and molecular knowledge to identify impactful precision breeding targets for relevant yield traits. The foundation for this is an understanding of yield formation physiology. Here, using soybean as an example, we provide a top-down review of yield physiology, starting with the fact that yield is derived from a population of plants growing together in a community. We review yield and yield-related components to provide a basic overview of yield physiology, synthesizing these concepts to highlight how such knowledge can be leveraged for soybean improvement. Using genome editing as an example, we discuss why multiple disciplines must be brought together to fully realize the promise of precision breeding-based crop improvement.
Solar Radiation Effects on Dry Matter Accumulations and Transfer in Maize
Solar radiation is the energy source for crop growth, as well as for the processes of accumulation, distribution, and transfer of photosynthetic products that determine maize yield. Therefore, learning the effects of different solar radiation amounts on maize growth is especially important. The present study focused on the quantitative relationships between solar radiation amounts and dry matter accumulations and transfers in maize. Over two continuous years (2017 and 2018) of field experiments, maize hybrids XY335 and ZD958 were grown at densities of 4.5 × 10 4 (D1), 7.5 × 10 4 (D2), 9 × 10 4 (D3), 10.5 × 10 4 (D4), and 12 × 10 4 (D5) plants/ha at Qitai Farm (89°34′E, 44°12′N), Xinjiang, China. Shading levels were 15% (S1), 30% (S2), and 50% (S3) of natural light and no shading (CK). The results showed that the yields of the commonly planted cultivars XY335 and ZD958 at S1, S2, and S3 (increasing shade treatments) were 7.3, 21.2, and 57.6% and 11.7, 31.0, and 61.8% lower than the control yields, respectively. Also, vegetative organ dry matter translocation (DMT) and its contribution to grain increased as shading levels increased under different densities. The dry matter assimilation amount after silking (AADMAS) increased as solar radiation and planting density increased. When solar radiation was <580.9 and 663.6 MJ/m 2 , for XY335 and ZD958, respectively, the increase in the AADMAS was primarily related to solar radiation amounts; and when solar radiation was higher than those amounts for those hybrids, an increase in the AADMAS was primarily related to planting density. Photosynthate accumulation is a key determinant of maize yield, and the contributions of the vegetative organs to the grain did not compensate for the reduced yield caused by insufficient light. Between the two cultivars, XY335 showed a better resistance to weak light than ZD958 did. To help guarantee a high maize yield under weak light conditions, it is imperative to select cultivars that have great stay-green and photosynthetic efficiency characteristics.
Growth Analysis of Glyphosate‐Resistant and Susceptible Amaranthus palmeri Biotypes
This study examined the growth parameters of both glyphosate‐susceptible and glyphosate‐resistant biotypes of Amaranthus palmeri, designated as GA2005 and GA2017, respectively. A two‐year microplot field study was conducted to assess their growth characteristics. Scheduled destructive harvests on named harvest days (HD) were conducted to collect measurements for further calculation of net assimilation rate (NAR; g m−2 day−1), specific leaf area (SLA), leaf weight ratio (LWR), stem‐to‐leaf ratio (SLR), leaf area index (LAI), leaf area ratio (LAR; cm2 g−1), leaf area duration (LAD; days), relative growth rate (RGR; g.g−1 day−1) and plant volume (m3). In addition, stem diameter, number of leaves, and Chlorophyll content (μmol m2) were determined. The main objective was to identify growth parameters that differentiate biotypes along the plant life cycle. While certain growth parameters showed no variation among biotypes, differences in leaf area index (LAI) over HD and chlorophyll content and leaf area duration (LAD) were observed as the main effects. Glyphosate‐resistant biotypes exhibited higher LAD and chlorophyll content, potentially conferring a competitive advantage, especially in heavily used glyphosate environments. The study highlights the complexity of intraspecific genetic differentiation, adaptation, and environmental factors affecting A. palmeri. It may offer insights into biotype distinction and resistance spread while advancing our comprehension of species adaptation and growth strategies for enhanced control. The growth patterns of weed populations across diverse geographical regions could impact the growth and development disparities between Palmer amaranth biotypes, revealing insights into their intraspecific growth strategies. Notably, leaf area index (LAI), leaf area duration (LAD), and chlorophyll content (μmol m2) emerged as the most distinctive parameters during the evaluation of glyphosate‐susceptible and resistant biotypes.
Ridge-Furrow Planting with Nitrogen Application Enhanced Rainfed Maize Yield and Water Productivity by Improving Leaf Photosynthetic Capacity
Leaf photosynthesis plays an important role in maize growth and yield components due to its involvement in dry matter partitioning and organ formation. Nevertheless, how varying planting patterns affect maize leaf photosynthesis, chlorophyll fluorescence and subsequently maize yield remains poorly understood, particularly at various nitrogen rates. A two-season field experiment was performed on rainfed maize in 2021 and 2022 to explore the responses of photosynthetic physiological characteristics, leaf N and chlorophyll contents, chlorophyll fluorescence parameters, grain yield and water productivity to various planting patterns and N rates. The experiment included six planting patterns, i.e., flat planting without mulching (CK), flat planting with straw mulching (SM), ridge mulched with transparent film and furrow without mulching (RP1), flat planting with full transparent film mulching (FM1), ridge mulched with black film and furrow without mulching (RP2), and flat planting with full black film mulching (FM2). Additionally, there were two nitrogen rates, i.e., 0 kg N ha−1 (N0) and 180 kg N ha−1. The results showed that nitrogen application significantly improved leaf physiological characteristics. Under various planting patterns, leaf photosynthetic pigments, leaf area duration, leaf nitrogen content, QYmax and ΦPSII ranked as RP2 > RP1(FM2) > FM1 > SM(CK) in 2021, and RP2(RP1) > FM1(FM2) > SM(CK) in 2022. No significant variations were observed in water productivity (WP) among different film colors, with overall performance of RP2(FM2) > RP1(FM1) > SM > CK. WP significantly improved by 36.14% and 25.15% under N1 compared to N0 in 2021 and 2022, respectively. This pattern paralleled the fluctuation in water consumption intensity. Compared to CK, RP significantly increased leaf nitrogen content (29.3%), total Chl content (16.0%), QYmax (6.39%), ΦPSII (32.01%), and net photosynthesis rate (14.2%), thereby significantly improving grain yield (46.35%) and WP (27.69%), while reducing evapotranspiration (6.84%). Yield performance ranked as RP2 > (RP1 and FM2) > FM1 > SM > CK in 2021 and RP2 > RP1 > (FM1 and FM2) > SM > CK in 2022. Overall, RP2N1 obtained the highest principal component scores in both years, suggesting great potential to improve leaf photosynthetic physiological characteristics, thereby increasing grain production and ensuring food security in rainfed maize cultivation areas.
Ability of Different Growth Indicators to Detect Salt Tolerance of Advanced Spring Wheat Lines Grown in Real Field Conditions
Plant growth indicators (GIs) are important for evaluating how different genotypes respond to normal and stress conditions separately. They consider both the morphological and physiological components of plants between two successive growth stages. Despite their significance, GIs are not commonly used as screening criteria for detecting salt tolerance of genotypes. In this study, 36 recombinant inbred lines (RILs) along with four genotypes differing in their salt tolerance were grown under normal and 150 mM NaCl in a two-year field trial. The performance and salt tolerance of these germplasms were assessed through various GIs. The analysis of variance showed highly significant variation between salinity levels, genotypes, and their interaction for all GIs and other traits in each year and combined data for two years, with a few exceptions. All traits and GIs were significantly reduced by salinity stress, except for relative growth rate (RGR), net assimilation rate (NAR), and specific leaf weight (SLW), which increased under salinity conditions. Traits and GIs were more correlated with each other under salinity than under normal conditions. Principal component analysis organized traits and GIs into three main groups under both conditions, with RGR, NAR, and specific leaf area (SLA) closely associated with grain yield (GY) and harvest index, while leaf area duration (LAD) was closely associated with green leaf area (GLA), plant dry weight (PDW), and leaf area index (LAI). A hierarchical clustering heatmap based on GIs and traits organized germplasms into three and four groups under normal and salinity conditions, respectively. Based on the values of traits and GIs for each group, the germplasms varied from high- to low-performing groups under normal conditions and from salt-tolerant to salt-sensitive groups under salinity conditions. RGR, NAR, and LAD were important factors determining genotypic variation in GY of high- and low-performing groups, while all GIs, except leaf area duration (LAR), were major factors describing genotypic variation in GY of salt-tolerant and salt-sensitive groups. In conclusion, different GIs that reveal the relationship between the morphological and physiological components of genotypes could serve as valuable selection criteria for evaluating the performance of genotypes under normal conditions and their salt tolerance under salinity stress conditions.
Effects of Nitrogen Fertilizer Management on Dry Matter Accumulation and Yield of Drip-Irrigated Sugar Beet in Arid Areas
Clarifying the optimal combination of N fertilizer application rate and application method can maximize the yield of drip-irrigated sugar beet in arid areas, which is of great significance for reducing farmland N pollution and achieving sustainable agricultural development. In this three-year field experiment in Xinjiang, China, the effects of three N application rates [75 kg ha−1 (N1), 150 kg ha−1 (N2), and 225 kg ha−1 (N3)] and three N application methods [the proportion of N applied at canopy rapid growth stage, taproot expansion stage, and sugar accumulation stage were (M1) 100%: 0%: 0%, (M2) 70%: 30%: 0%, and (M3) 50%: 30%: 20%] on the dry matter accumulation (DMA) and distribution, leaf senescence, yield, and agronomic N use efficiency (aNUE) of drip-irrigated sugar beet were explored. The results showed that N application (N1, N2, and N3 treatments) increased the shoot DMA by 27.7% (three-year average), 52.6%, and 83.1%, and the taproot DMA by 28.3%, 43.2%, and 61.6%, respectively (p < 0.05), compared with CK (no N supply) treatment. The N application methods M2 and M3 increased the shoot DMA by 5.6% (three-year average) and 1.0% (p > 0.05), respectively, and the taproot DMA by 7.2% and 3.6% (p < 0.05), respectively, compared with M1. In addition, M2 could delay the end of shoot and taproot growth (te) and the occurrence of maximum growth rate (tm). In particular, the N3M2 treatment increased the leaf area index (LAI) by 20.4–75.9% (p < 0.05) compared with other treatments by increasing the leaf area duration (LAD) and decreasing the leaf senescence rate (LSR). The taproot yield and sugar yield of N3M2 treatment reached the maximum at harvest time, but there was no significant difference in taproot yield and sugar yield between N3M2 treatment and N2M2 treatment. The aNUE in N2M2 treatment was the highest (p < 0.05), which was 1.29–7.85 times higher than that of other treatments. Therefore, reducing the N application rate from 225 kg·ha−1 to 150 kg·ha−1 and applying 70% and 30% of 150 kg N ha−1 at the canopy rapid growth stage and the taproot expansion stage, respectively, could achieve the goal of increasing sugar beet yield and N use efficiency. This study will provide an important reference for the sustainable production of sugar beet under drip irrigation in Xinjiang, China.
Development of a Critical Nitrogen Dilution Curve Based on Leaf Area Duration in Wheat
Precise quantification of plant nitrogen (N) nutrition status is essential for crop N management. The concept of critical N concentration (Nc) has been widely used for assessment of plant N status. This study aimed to develop a new winter wheat Nc dilution curve based on leaf area duration (LAD). Four field experiments were performed on different cultivars with different N fertilization modes in the Yangtze River basin and Yellow River basin in China. Results showed that the increase in LAD with increasing cumulative thermal time took the shape of an \"S\" type curve; whereas shoot N concentration decreased with increasing LAD, according to a power function. Both LAD and shoot N concentration increased with increasing N application. The new LAD based Nc dilution curve was determined and described as Nc = 1.6774 LAD when LAD > 0.13. However, when LAD ≤ 0.13, Nc was constant and can be calculated by the equation when LAD = 0.13. The validation of Nc dilution curve with dataset acquired from independent experiments confirmed that N nutrition index (NNI) predictions based on the newly established Nc dilution curve could precisely diagnose N deficiency at different plant growth stages. The integrated N nutrition index (NNI ), which was obtained by the weighted mean of NNI, was used to estimate shoot N concentration, shoot dry matter, LAD, and yield using regression functions. The linear relationships between NNI and these growth variables were well correlated. These results provided enough evidence that the new LAD-based Nc dilution curve could effectively and precisely diagnoses N deficiency in winter wheat crops.
Potato Growth and Yield Characteristics under Different Cropping System Management Strategies in Northeastern U.S
Cropping systems and management practices that improve soil health may greatly enhance crop productivity. Four different potato cropping systems designed to address specific management goals of soil conservation (SC), soil improvement (SI), disease suppression (DS), and a status quo (SQ) standard rotation, along with a non-rotation (PP) control, were evaluated for their effects on potato crop growth, nutrient, and yield characteristics under both irrigated and non-irrigated (rainfed) conditions in field trials in Maine, USA, from 2004 to 2010. Both cropping system and irrigation significantly (p < 0.05) affected most potato crop parameters associated with growth and yield. All rotations increased tuber yield relative to the non-rotation PP control, and the SI system, which included yearly compost amendments, resulted in overall higher yields and a higher percentage of large-size tubers than all other systems with no irrigation (increases of 14 to 90%). DS, which contained disease-suppressive green manures and cover crops, produced the highest yields overall under irrigation (increases of 11 to 35%). Irrigation increased tuber yields in all cropping systems except SI (average increase of 27–37%). SI also resulted in significant increases in leaf area duration and chlorophyll content (as indicators of photosynthetic potential) and root and shoot biomass relative to other cropping systems, particularly under non-irrigated conditions. SI also resulted in higher shoot and tuber tissue concentrations of N, P, and K, but not most micronutrients. Overall, cropping systems that incorporate management practices such as increased rotation length and the use of cover crops, green manures, reduced tillage, and particularly, organic amendments, can substantially improve potato crop growth and yield. Irrigation also substantially increased growth and yield under normal field conditions in Maine, but SI, with its large organic amendments, was essentially a substitute for irrigation, producing comparable results without irrigation.
Biostimulants and calcium-mediated optimization in morpho-phenological growth of mung bean (Vigna radiata L.) in the summer season
Mung bean, botanically referred to as Vigna radiata is valued for its superb quality of nutrition, which includes a large amount of protein, minerals, and vitamins, making it a staple worldwide. Morpho-phenological traits are critical indicators of plant growth and development, which influence the overall yield and quality of the mung bean; thus, optimizing these traits can improve the yield barriers. Therefore, this study aimed to analyze the impact of biostimulants and calcium-mediated response on the morpho-phenological growth of mung bean while assessing the growth, plant height (cm), number of leaves, leaf area  plant-1 (cm²), leaf area index (LAI), crop growth rate (CGR), leaf area duration (LAD), SPAD reading, and total chlorophyll content (mg g-1) were used. Among the treatment combinations, T7 (Calcium, 10mM + Bio-priming with Rhizobium + Putrescine, 3mM) showed statistically significant improvements (p <0.05%) in all measured parameters. This treatment yielded the highest values across the board. The second-best results were observed with the T5 (Calcium, 10mM + Putrescine, 3mM), which also showed significant improvements for most of the parameters at both intervals, i.e. 30 and 60 days after sowing (DAS). Moreover, the analysis of the data in terms of percent increase/decrease over control produced a clear view of the morpho-physiological growth in the T7 and T5 treatments compared to the control, highlighting their effectiveness. Overall, this study revealed the significance of a synergistic approach of calcium, putrescine, and biopriming with rhizobium to optimize the morpho-phenological traits and enhance the yield of mung bean in the summer season.   
Nitrogen and plant population change radiation capture and utilization capacity of sunflower in semi-arid environment
The combination of nitrogen and plant population expresses the spatial distribution of crop plants. The spatial distribution influences canopy structure and development, radiation capture, accumulated intercepted radiation (Sa), radiation use efficiency (RUE), and subsequently dry matter production. We hypothesized that the sunflower crop at higher plant populations and nitrogen (N) rates would achieve early canopy cover, capture more radiant energy, utilize radiation energy more efficiently, and ultimately increase economic yield. To investigate the above hypothesis, we examined the influences of leaf area index (LAI) at different plant populations (83,333, 66,666, and 55,555 plants ha −1 ) and N rates (90, 120, and 150 kg ha −1 ) on radiation interception (Fi), photosynthetically active radiation (PAR) accumulation (Sa), total dry matter (TDM), achene yield (AY), and RUE of sunflower. The experimental work was conducted during 2012 and 2013 on sandy loam soil in Punjab, Pakistan. The sunflower crop captured more than 96% of incident radiant energy (mean of all treatments), 98% with a higher plant population (83,333 plants ha −1 ), and 97% with higher N application (150 kg ha −1 ) at the fifth harvest (60 days after sowing) during both study years. The plant population of 83,333 plants ha −1 with 150 kg N ha −1 ominously promoted crop, RUE, and finally productivity of sunflower (AY and TDM). Sunflower canopy (LAI) showed a very close and strong association with Fi ( R 2  = 0.99 in both years), PAR ( R 2  = 0.74 and 0.79 in 2012 and 2013, respectively), TDM ( R 2  = 0.97 in 2012 and 0.91 in 2013), AY ( R 2  = 0.95 in both years), RUE for TDM (RUE TDM ) ( R 2  = 0.63 and 0.71 in 2012 and 2013, respectively), and RUE for AY (RUE AY ) ( R 2  = 0.88 and 0.87 in 2012 and 2013, respectively). Similarly, AY ( R 2  = 0.73 in 2012 and 0.79 in 2013) and TDM ( R 2  = 0.75 in 2012 and 0.84 in 2013) indicated significant dependence on PAR accumulation of sunflower. High temperature during the flowering stage in 2013 shortened the crop maturity duration, which reduced the LAI, leaf area duration (LAD), crop growth rate (CGR), TDM, AY, Fi, Sa, and RUE of sunflower. Our results clearly revealed that RUE was enhanced as plant population and N application rates were increased and biomass assimilation in semi-arid environments varied with radiation capture capacity of sunflower.