scholarly journals La importancia del intervalo de la floración en el mejoramiento para la resistencia a sequía en maíz tropical

2016 ◽  
Vol 1 ◽  
pp. 45 ◽  
Author(s):  
J. Bolaños ◽  
G. O. Edmeades
Keyword(s):  
Grain Yield ◽  
Recurrent Selection ◽  
Water Status ◽  
Effective Means ◽  
Chlorophyll Concentration ◽  
Canopy Temperature ◽  
Shoot Elongation ◽  
Potential Yield ◽  
Erect Leaves ◽  
Bidirectional Selection

The length of the Interval between anthesis and silking (ASI) is increased by drought which coincides with flowering. Four elite CIMMYT lowland tropical populations are undergoing recurrent selection (S1 or full-sib) for improved grain yield and several other traits under drought and well watered conditions. Data collected from more than 200 families per population grown In single row plots under three water stress levels (pre and post-flowering stress; post-flowering stress; normal irrigation, all in the absence of rain) showed weak or no correlation between grain yield and traits related to plant water status, such as leaf rolling and senescence, photooxidation, leaf chlorophyll concentration, shoot elongation rate, canopy temperature and predawn water potential. Yield under all levels of stress was significantly negatively correlated with AST, and as AST increased due to drought, kernels and ears per plant were significantly reduced. In all populations yield decreased by approximately 10 % per day increase in AST up to 8 days. In several stress situations broad-sense heritability of AST was greater than that of grain yield and the genetic correlation between grain yield and AST approached -1.00. Synthetics formed from one population following bidirectional selection and tested under drought showed adaptive advantage of cool canopy temperature, delayed leaf senescence, reduced AST and erect leaves, especially when all were combined with grain yield in a single index during selection. Selection for reduced AST and high grain yield under drought can be an effective means of improving drought tolerance in tropical maize.

scholarly journals Thermal Imaging Reliability for Estimating Grain Yield and Carbon Isotope Discrimination in Wheat Genotypes: Importance of the Environmental Conditions

Sensors ◽  
2019 ◽  
Vol 19 (12) ◽  
pp. 2676 ◽  
Author(s):  
Sebastián Romero-Bravo ◽  
Ana María Méndez-Espinoza ◽  
Miguel Garriga ◽  
Félix Estrada ◽  
Alejandro Escobar ◽  
...  
Keyword(s):  
Grain Yield ◽  
Thermal Imaging ◽  
Mediterranean Climate ◽  
Vapor Pressure Deficit ◽  
Stress Condition ◽  
Water Status ◽  
Canopy Temperature ◽  
Spring Bread Wheat ◽  
Wheat Genotypes ◽  
The Relationship

Canopy temperature (Tc) by thermal imaging is a useful tool to study plant water status and estimate other crop traits. This work seeks to estimate grain yield (GY) and carbon discrimination (Δ13C) from stress degree day (SDD = Tc − air temperature, Ta), considering the effect of a number of environmental variables such as the averages of the maximum vapor pressure deficit (VPDmax) and the ambient temperature (Tmax), and the soil water content (SWC). For this, a set of 384 and a subset of 16 genotypes of spring bread wheat were evaluated in two Mediterranean-climate sites under water stress (WS) and full irrigation (FI) conditions, in 2011 and 2012, and 2014 and 2015, respectively. The relationship between the GY of the 384 wheat genotypes and SDD was negative and highly significant in 2011 (r2 = 0.52 to 0.68), but not significant in 2012 (r2 = 0.03 to 0.12). Under WS, the average GY, Δ13C, and SDD of wheat genotypes growing in ten environments were more associated with changes in VPDmax and Tmax than with the SWC. Therefore, the amount of water available to the plant is not enough information to assume that a particular genotype is experiencing a stress condition.

scholarly journals Combined Use of Low-Cost Remote Sensing Techniques and δ13C to Assess Bread Wheat Grain Yield under Different Water and Nitrogen Conditions

Agronomy ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 285 ◽  
Author(s):  
Salima Yousfi ◽  
Adrian Gracia-Romero ◽  
Nassim Kellas ◽  
Mohamed Kaddour ◽  
Ahmed Chadouli ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Grain Yield ◽  
Water Status ◽  
Low Cost ◽  
Vegetation Indices ◽  
Carbon Isotopic Composition ◽  
Canopy Temperature ◽  
N Fertilization ◽  
Canopy Area ◽  
Rgb Images

Vegetation indices and canopy temperature are the most usual remote sensing approaches to assess cereal performance. Understanding the relationships of these parameters and yield may help design more efficient strategies to monitor crop performance. We present an evaluation of vegetation indices (derived from RGB images and multispectral data) and water status traits (through the canopy temperature, stomatal conductance and carbon isotopic composition) measured during the reproductive stage for genotype phenotyping in a study of four wheat genotypes growing under different water and nitrogen regimes in north Algeria. Differences among the cultivars were reported through the vegetation indices, but not with the water status traits. Both approximations correlated significantly with grain yield (GY), reporting stronger correlations under support irrigation and N-fertilization than the rainfed or the no N-fertilization conditions. For N-fertilized trials (irrigated or rainfed) water status parameters were the main factors predicting relative GY performance, while in the absence of N-fertilization, the green canopy area (assessed through GGA) was the main factor negatively correlated with GY. Regression models for GY estimation were generated using data from three consecutive growing seasons. The results highlighted the usefulness of vegetation indices derived from RGB images predicting GY.

scholarly journals Estimating the Leaf Water Status and Grain Yield of Wheat under Different Irrigation Regimes Using Optimized Two- and Three-Band Hyperspectral Indices and Multivariate Regression Models

Water ◽  
2021 ◽  
Vol 13 (19) ◽  
pp. 2666
Author(s):  
Salah Elsayed ◽  
Salah El-Hendawy ◽  
Yaser Hassan Dewir ◽  
Urs Schmidhalter ◽  
Hazem H. Ibrahim ◽  
...  
Keyword(s):  
Grain Yield ◽  
Water Content ◽  
Multivariate Regression ◽  
Regression Models ◽  
Plant Traits ◽  
Water Status ◽  
Growth Conditions ◽  
Leaf Water Status ◽  
Potential Yield ◽  
Irrigation Regimes

Spectral reflectance indices (SRIs) often show inconsistency in estimating plant traits across different growth conditions; thus, it is still necessary to develop further optimized SRIs to guarantee the performance of SRIs as a simple and rapid approach to accurately estimate plant traits. The primary goal of this study was to develop optimized two- and three-band vegetation- and water-SRIs and to apply different multivariate regression models based on these SRIs for accurately estimating the relative water content (RWC), gravimetric water content (GWCF), and grain yield (GY) of two wheat cultivars evaluated under three irrigation regimes (100%, 75%, and 50% of crop evapotranspiration (ETc)) for two seasons. Results showed that the three plant traits and all SRIs showed significant differences (p < 0.05) between the three irrigation treatments for each wheat cultivar. The three-band water-SRIs (NWIs-3b) showed the best performance in estimating the three plant traits for both cultivars (R2 > 0.80), and RWC and GWCF under 75% ETc (R2 ≥ 0.65). Four out of six three-band vegetation-SRIs (NDVIs-3b) performed better than any other SRIs for estimating GY under 100% ETc and 50% ETC, and RWC under 100% ETc (R2 ≥ 0.60). All types of SRIs demonstrated excellent performance in estimating the three plant traits (R2 ≥ 0.70) when the data of all growth conditions were combined and analyzed together. The NWIs-3b coupled with Random Forest models predicted the three plant traits with satisfactory accuracy for the calibration (R2 ≥ 0.96) and validation (R2 ≥ 0.93) datasets. The overall results of this study elucidate that extracting an optimized NWIs-3b from the full spectrum data and combined with an appropriate regression technique could be a practical approach for managing deficit irrigation regimes of crops through accurately, timely, and non-destructively monitoring the water status and final potential yield.

Effects of Photoinhibition Induced by Water Stress on Growth and Yield of Grain Sorghum

1988 ◽  
Vol 15 (2) ◽  
pp. 179 ◽  
Author(s):  
MM Ludlow ◽  
SB Powles
Keyword(s):  
Water Stress ◽  
Grain Yield ◽  
Water Status ◽  
Grain Sorghum ◽  
Growth And Yield ◽  
Grain Number ◽  
Potential Yield ◽  
Carbon Supply ◽  
Matter Production ◽  
Absorption Of Light

The significance of photoinhibition induced by water stress for growth and grain yield of sorghum was investigated by shading water-stressed plants for a 7-day period during panicle development. Thereafter, shading was removed, stressed plants were rewatered, and all plants were kept well-watered until physiological maturity. Shading water-stressed plants for a 7-day period increased grain number and grain yield of primary heads by 10- and 13-fold, respectively. Even though plants were severely stressed, photoinhibition was only 20%. Moreover, reduction of photoinhibition by shading did not improve carbon supply to the developing panicle. Therefore, the response of grain yield to shading was attributed to a 15% higher average leaf water potential in shaded plants, which arose despite attempts to keep water status similar in shaded and unshaded plants. The effect of water stress on the primary head was so severe that many plants produced secondary heads. The grain yield from these secondary heads compensated for the low yield of primary heads so that the total dry matter production and total grain yield of water-stressed plants were similar to those of unstressed plants. In view of the ability of this relatively determinate species to compensate for potential yield losses, as well as the mechanisms to avoid water stress, high temperatures and excessive absorption of light, it seems unlikely that photoinhibition induced by water stress will be of agronomic significance in grain sorghum.

scholarly journals Potential yield of soybean promising lines in acid soil of Central Lampung, Indonesia

2014 ◽  
Vol 5 (1) ◽  
Author(s):  
Heru Kuswantoro
Keyword(s):  
Grain Yield ◽  
Seed Size ◽  
Seed Yield ◽  
Soil Ph ◽  
Acid Soil ◽  
Potential Yield ◽  
Climate Conditions ◽  
Check Variety ◽  
Similar Soil

Most of Indonesia dryland is covered by acid soil which lead to the decreasing potential yield of the crops. In different areas soybean potential yield also different depends on the different soil pH and the availability of the soil. The objective of the research was to study the potential yield of soybean promising lines in acid soil of Central Lampung, Indonesia. Ten promising lines and two check varieties (Tanggamus and Wilis) were grown in acid soil with pH 4.7. The results showed that the highest seed yield was showed by SC5P2P3.5.4.1-5 with 2.51 t/ha. Other soybean promising lines with seed yield over than 2 t/ha-1 was SJ-5/Msr.99.5.4.5-1-6-1 and the check variety Tanggamus. The highest yield of SC5P2P3.5.4.1-5 was caused by the high number of filled pods and the large of seed size. Other nine promising lines also can be developed to obtained grain yield as many as Tanggamus yield in the area with similar soil and climate conditions.

CANOPY TEMPERATURE AS AN INDICATOR OF WATER STATUS IN CITRUS TREES

2011 ◽  
pp. 347-353 ◽  
Author(s):  
F. Stagno ◽  
A. Giuffrida ◽  
F. Intrigliolo
Keyword(s):  
Water Status ◽  
Canopy Temperature ◽  
Citrus Trees

scholarly journals Selección para calidad fisiológica de la semilla y rendimiento en líneas S2 derivadas de cuatro poblaciones tropicales de maíz (Zea mays L.)

2016 ◽  
Vol 7 (1) ◽  
pp. 58
Author(s):  
Enrique Navarro ◽  
Cristina Vega ◽  
Fernando Narváez ◽  
Hugo Córdova
Keyword(s):  
Genetic Variability ◽  
Grain Yield ◽  
Recurrent Selection ◽  
Zea Mays L ◽  
Agronomic Traits ◽  
Reciprocal Recurrent Selection ◽  
Laboratory Conditions ◽  
Flower Plant ◽  
Ear Height ◽  
Field And Laboratory Conditions

This study was carried out in 1993 to evaluate S2 lines from four maize tropical populations improved by reciprocal recurrent selection. These lines were evaluated under field and laboratory conditions, the latter one to determine physiology quality. The main goal was to measure genetic variability within and among populations for traits such as grain yield, vigor and germination and to select the best lines under field and laboratory conditions. The combined analysis of variance showed great genetic variability among the S2 lines within and among populations for grain yield, days to flower, plant and ear height, among others. The maximum genetic variability was observed on the lines from population 43 and pool 23 for most of the traits, although the latter showed a greater genetic variability for grain yield. Besides, it is important to mention that the above populations included the best genotypes for grain yield, germination and vigor. Taking into account the above mentionel agronomic traits, fifteen lines were selected; 2 belong to population 43* pool 20, 2 from pool 19* pool 23, 8 from population 43, and 3 from pool 23. These results confirm the genetic superiority of the lines from populations 43 and pool 23, so that these populations should be recommended for future genetic improvement by reciprocal recurrent procedures.

scholarly journals Microtensiometers Accurately Measure Stem Water Potential in Woody Perennials

Plants ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 2780
Author(s):  
Victor Blanco ◽  
Lee Kalcsits
Keyword(s):  
Water Potential ◽  
Leaf Gas Exchange ◽  
Water Status ◽  
Full Range ◽  
Canopy Temperature ◽  
Plant Water ◽  
Stem Water Potential ◽  
Woody Tissue ◽  
Woody Perennials ◽  
Stem Water

Stem water potential (Ψstem) is considered to be the standard measure of plant water status. However, it is measured with the pressure chamber (PC), an equipment that can neither provide continuous information nor be automated, limiting its use. Recent developments of microtensiometers (MT; FloraPulse sensors), which can continuously measure water tension in woody tissue of the trunk of the tree, can potentially highlight the dynamic nature of plant water relations. Thus, this study aimed to validate and assess the usefulness of the MT by comparing the Ψstem provided by MT with those same measurements from the PC. Here, two irrigation treatments (a control and a deficit treatment) were applied in a pear (Pyrus communis L.) orchard in Washington State (USA) to capture the full range of water potentials in this environment. Discrete measurements of leaf gas exchange, canopy temperature and Ψstem measured with PC and MT were made every two hours for four days from dawn to sunset. There were strong linear relationships between the Ψstem-MT and Ψstem-PC (R2 > 0.8) and with vapor pressure deficit (R2 > 0.7). However, Ψstem-MT was more variable and lower than Ψstem-PC when Ψstem-MT was below −1.5 MPa, especially during the evening. Minimum Ψstem-MT occurred later in the afternoon compared to Ψstem-PC. Ψstem showed similar sensitivity and coefficients of variation for both PC and MT acquired data. Overall, the promising results achieved indicated the potential for MT to be used to continuously assess tree water status.

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