scholarly journals Heritability and Correlations for Agronomic and Physiologic Traits of Maize under Deficit Irrigation at Two Growth Stages

2019 ◽  
pp. 1-17
Author(s):  
A. M. M. Al-Naggar ◽  
M. M. Shafik ◽  
M. O. A. Elsheikh
Keyword(s):  
Drought Tolerance ◽  
Selection Criteria ◽  
Chlorophyll Concentration ◽  
Grain Filling ◽  
Kernel Weight ◽  
Stem Diameter ◽  
Growth Stages ◽  
Tolerance Index ◽  
Genetic Advance ◽  
Maize Genotypes

Strong associations between agronomic and physiologic traits and drought tolerance, high heritability and high genetic advance for such traits would allow plant breeder to use such traits as selection criteria for selecting drought tolerant genotypes. The objectives of the present investigation were: (i) to explain the relationships between the drought tolerance index (DTI) and 14 agronomic and physiologic traits of 22 maize genotypes and (ii) to estimate the broad-sense heritability (h2b) and genetic advance (GA) from selection for such traits, in order to determine the selection criteria for DTI. A two-year experiment was carried out using a split plot experiment with three replications. The main plots were devoted to irrigation regimes, i.e. well watering (WW), water stress at flowering (WSF) and at grain filling (WSG), and sub plots to maize genotypes. It is evident from results that the best selection criteria for drought tolerance in our study were: 100-kernel weight (100KW) and chlorophyll concentration index (CCI) under WSF and WSG, anthesis-silking interval (ASI), upper stem diameter (SDU) and lower stem diameter (SDL) under WSF and kernels/row (KPR) and ear leaf area (ELA) under WSG, since they show high correlation (r) values with grain yield/plant (GYPP), high h2b and high GA estimates under the respective environments. Under well watering conditions, KPR, 100KW, CCI, and SDL traits showed high (r) values, high h2b and high GA estimates and therefore could be considered selection criteria for GYPP under non-stressed environment. The results concluded that predicted selection gain would be higher if selection was practiced under WW for lower values of days to silking and higher values of ears/plant, rows/ear, KPR, 100KW, SDU and SDL, under WSF for lower values of ASI and higher values of GYPP and under WSG for lower values of plant height, ear height, and barren stalks, and higher values of CCI and ELA.

scholarly journals Selection Criteria and Selection Environment for Drought Tolerance of Egyptian Wheat (Triticum aestivum L.) Landraces

2020 ◽  
pp. 25-40
Author(s):  
Ahmed Medhat Mohamed Al-Naggar ◽  
Mohamed Abd El-Maboud Abd El-Shafi ◽  
Mohamed Helmy El-Shal ◽  
Ali Hassan Anany
Keyword(s):  
Drought Tolerance ◽  
Grain Yield ◽  
Selection Criteria ◽  
Selection Criterion ◽  
Correlation Coefficients ◽  
Grain Filling ◽  
Triticum Aestivum L ◽  
Genetic Advance ◽  
Selection Environment ◽  
Selection For

Strong correlations between wheat traits and drought tolerance (DT) associated with high heritability and high genetic advance from selection would allow plant breeder to use such traits as selection criteria. The objective of the present investigation was to determine the optimum selection criteria and selection environment for drought tolerance via estimation of correlation coefficients (r) among 13 agronomic, grain yield and quality traits and DT of 20 wheat landraces, broad-sense heritability (h2b) and genetic advance (GA) from selection for such traits under well-watered (WW) and water stressed (WS) environments. A two-year experiment was carried out using a split-plot design with four replications. Results concluded that the best selection criterion for drought tolerance in our study was grain yield/plant (GYPP), followed by a number of grains/spike (GPS), grain filling period (GFP), grain starch (GSC) and protein (GPC) content, plant height (PH) and days to maturity (DTM), since they showed high (r), high h2b and high GA estimates. The best selection environment was WW for days to anthesis, PH, spikes/plant, GPS, spikelets/spike, GYPP, GPC and WS for DTM, GFP, GSC and thousand-grain weight traits. This information could help future breeding programs in selection for improving drought tolerance of wheat.

scholarly journals Water Use Efficiency of Maize Genotypes of Different Maturity Groups at Seedling and Grain-filling Growth Stages in a Rainforest Location

2019 ◽  
pp. 1-11
Author(s):  
O. O. Bankole ◽  
A. Oluwaranti ◽  
F. E. Awosanmi
Keyword(s):  
Water Use Efficiency ◽  
Water Use ◽  
Growth Stage ◽  
Grain Filling ◽  
Growth Stages ◽  
Maturity Group ◽  
Maize Genotypes ◽  
Early Maturing ◽  
Use Efficiency ◽  
Maturity Groups

Aims: The objectives of this study were to evaluate maize genotypes of different maturity groups for seedling and grain filling water use efficiency and determine relationship that exist between the water use efficiency traits and yield of different maize maturity groups. Study Design:  Sixteen maize genotypes were planted in Randomized Complete Block Design in three replicates for emergence, vegetative, water use efficiency traits at the seedling and grain-filling growth stages and yield. Place and Duration of Study: The sixteen maize genotypes of different maturity groups were evaluated during the early and late cropping seasons of 2016 at the Obafemi Awolowo University Teaching and Research Farm, Ile-Ife, Nigeria Methodology: Data collected were subjected to Analysis of Variance (ANOVA), correlation analysis among water use efficiency traits and yield for each of the maturity groups. Results: There was no significant difference among the genotypes within each maturity groups for water use efficiency at seedling and grain filling growth stages. The late maturity group of maize used more water at the seedling growth stage than the other maturity groups in the early season of this study while in the late season, the early and extra-early maturity groups used more water than the other maturity groups. Increase in emergence percentage, reduction in speed of germination, and minimal days to complete germination increased water use efficiency at the seedling stage only during the early cropping season. Efficiency of water usage at the seedling growth stage was more among the late and intermediate maturing groups than the extra-early and early maturing groups in the early season while in the late season, the extra-early and early maturing groups used water more efficiently than the late and Intermediate maturing groups Conclusion: Maturity group played a significant role in the expression and manifestation of water use efficiency traits under different environmental conditions.

scholarly journals Classification of genetic diversity for drought tolerance in maize genotypes through principal component analysis

2017 ◽  
Vol 62 (3) ◽  
pp. 213-227 ◽  
Author(s):  
Manal Hefny ◽  
Abdelraheim Ali ◽  
Tarek Byoumi ◽  
Mohamed Al-Ashry ◽  
Salah Okasha
Keyword(s):  
Drought Tolerance ◽  
Water Content ◽  
Peroxidase Activity ◽  
Water Scarcity ◽  
Relative Water Content ◽  
Field Experiments ◽  
Principal Component ◽  
Kernel Weight ◽  
Maize Genotypes ◽  
Relative Water

Water scarcity is a universal environmental constraint for agricultural sustainability and production. Two field experiments were accomplished during the 2012 and 2013 growing seasons in two sites: the experimental farm of Suez Canal University, Ismailia and Romana Province, North Sinai, Egypt to evaluate 21 genotypes of maize comprising six inbred lines and their 15 F1 crosses for their drought tolerance. The experiments were arranged as a split-plot design with three replications, where moisture levels (100 and 50% of evapotranspiration) and maize genotypes were allocated to main plots and sub-plots, respectively. Results showed reduction in performance for most measured traits in response to water stress with varying degrees with yield plant-1 being the most affected. Inversely, proline and relative water content and anthesis-silking interval were increased. Correlation results confirmed the reduced grain yield with the increasing anthesis-silking interval, and suggested kernels row-1, relative water content, peroxidase activity and rows ear-1 in Ismailia, and rows ear-1, relative water content, peroxidase activity, kernel weight in Romana were indirect selection criteria for increasing yield in water scarcity environments. Principal component (PC) analysis showed that three PCs having Eigen value >1 explained 70.67 and 70.16%; 69.79 and 71.38% of the total variability among genotypes in control and stress conditions in Ismailia and Romana, respectively. The crosses P1?P3, P4?P6, P3?P5 and P1?P5 were classified as drought tolerant under Ismailia and Romana conditions. On the other hand, P1xP4, P3xP4, and P4 were considered as drought sensitive in Ismailia conditions. In addition, P5, P2?P4, P1?P4 and P5?P6 were the most affected by water deficiency under Romana conditions.

Evaluation of the tolerance of Thai indigenous upland rice germplasm to early drought stress using multiple selection criteria

2015 ◽  
Vol 15 (2) ◽  
pp. 109-118 ◽  
Author(s):  
Kittichai Narenoot ◽  
Tidarat Monkham ◽  
Sompong Chankaew ◽  
Patcharin Songsri ◽  
Wattana Pattanagul ◽  
...  
Keyword(s):  
Drought Stress ◽  
Drought Tolerance ◽  
Selection Criteria ◽  
Upland Rice ◽  
Block Design ◽  
Rice Variety ◽  
Tolerance Index ◽  
Rice Varieties ◽  
Rice Germplasm ◽  
Drought Tolerance Index

Drought remains the most important factor that affects rice productivity, especially in rainfed areas, worldwide. Upland rice is one of the crop choices of farmers in the rainfed environment. Although upland rice varieties require less water than lowland rice varieties, yields often remain limited by drought, particularly in the period of early growth. The aims of this study were to identify the traits related to early drought tolerance in upland rice varieties, and to identify the potential sources of germplasm for early drought tolerance. A total of sixty upland rice varieties were planted in a factorial experiment with a randomized complete block design with 3 replications in the rainy seasons of 2011 and 2012, under greenhouse conditions. Based on the drought tolerance index (DTI), the test germplasm sources were classified into three groups: (i) susceptible; (ii) moderately tolerant; (iii) tolerant to drought stress. Grain yield (GY) showed significant negative correlations with the leaf rolling score (r= − 0.623, P< 0.01), the leaf death score (LDS) (r= − 0.673, P< 0.01) and the recovery score (r= − 0.746, P< 0.01), while leaf dry matter (r= 0.698, P< 0.01) and leaf water potential (r= 0.618, P< 0.01) had significant positive correlations with GY. These findings indicate the suitability of the DTI as the selection criteria for early drought tolerance in a breeding programme. In addition, the upland rice germplasm accessions KKU-ULR011, KKU-ULR012, KKU-ULR125, KKU-ULR199 and KKU-ULR292 were identified as having high levels of stability for drought tolerance in both the 2011 and 2012 experiments, suggesting their potential for further use for rice variety improvement for drought tolerance.

scholarly journals THE MORPHOLOGICAL CHANGE IN SUNFLOWER PLANT UNDER HARDENING CONDITIONS TO DROUGHT TOLERANCE . I. PLANT HEIGHT AND STEM DIAMETER

2009 ◽  
Vol 6 (2) ◽  
pp. 290-297
Author(s):  
Baghdad Science Journal
Keyword(s):  
Drought Tolerance ◽  
Plant Height ◽  
Field Experiments ◽  
Agricultural Practices ◽  
Stem Diameter ◽  
Growth Stages ◽  
Spring Season ◽  
Original Weight ◽  
Neutron Moisture ◽  
Tolerance Field

The objective of the work was to study the changes in height and stem diameter of sunflower plants during growth stages under hardening conditions to drought tolerance. Field experiments were carried out during the spring season of 2000 and2001. Agricultural practices were made according to recommendations.Asplit-split plots design was used with three replications.The main plots included irrigation treatments:irrigation to100%(full irrigation),75and50%of available water.The sub plots were the cultivars Euroflor and Flame.The sub-sub plots represented four seed soaking treatments:Control(unsoaking), soaking in water ,Paclobutrazol solution(250ppm),and Pix solution(500ppm). The soaking continued for 24 hours then seeds were dried at room temperature until they regained their original weight. Amount of water for each irrigation were calculated to satisfy water depletion in soil using a neutron moisture meter. Results showed that stress 600 and 800Kp caused asignificant decreasing in plan height and stem diameter at most growth stages in both seasons and as a mean of seasons.The decrease in plant height at physiological maturation as a mean of seasons were 12.62 and 14.29%, and stem diameter 11.94 and 9.41%, respectively compared with full irrigation.Euroflor was superior over Flame in plant height at most growth stages during spring season of 2000, while Flame was superior in plant height at most growth stages during spring season of 2001 ,and in stem diameter after 30 days from planting.Soaking the seeds presowing in paclobutrazol and pix solutions decreased plant height at most growth stages in both seasons and as a mean of seasons. The decrease at physiological maturation as amean of seasons were 4.49 and 2.78%compared with unsoaked , and 5.27 and 3.57% compared with soaking in water, respectively.On the other hand,soaking in paclobutrazol and pix solutions increased stem diameter at physiological maturation by 9.78 and 12.18% compared with unsoaked as a mean of seasons. In conclusion, that it could reduce plant height and increase stem diameter to support the plants to drought tolerance by soaking the seeds presowing in water or plant growth regulator

scholarly journals Global Transcriptome and Weighted Gene Co-expression Network Analyses of Growth-Stage-Specific Drought Stress Responses in Maize

2021 ◽  
Vol 12 ◽  
Author(s):  
Songtao Liu ◽  
Tinashe Zenda ◽  
Anyi Dong ◽  
Yatong Yang ◽  
Nan Wang ◽  
...  
Keyword(s):  
Drought Stress ◽  
Drought Tolerance ◽  
Transcriptome Analysis ◽  
Stress Responses ◽  
Growth Stage ◽  
Molecular Mechanisms ◽  
Grain Filling ◽  
Growth Stages ◽  
Specific Response ◽  
Network Analyses

Drought is the major abiotic stress threatening maize (Zea mays L.) production globally. Despite recent scientific headway in deciphering maize drought stress responses, the overall picture of key genes, pathways, and co-expression networks regulating maize drought tolerance is still fragmented. Therefore, deciphering the molecular basis of maize drought tolerance remains pertinent. Here, through a comprehensive comparative leaf transcriptome analysis of drought-tolerant hybrid ND476 plants subjected to water-sufficient and water-deficit treatment conditions at flared (V12), tasseling (VT), the prophase of grain filling (R2), and the anaphase of grain filling (R4) crop growth stages, we report growth-stage-specific molecular mechanisms regulating maize drought stress responses. Based on the transcriptome analysis, a total of 3,451 differentially expressed genes (DEGs) were identified from the four experimental comparisons, with 2,403, 650, 397, and 313 DEGs observed at the V12, VT, R1, and R4 stages, respectively. Subsequently, 3,451 DEGs were divided into 12 modules by weighted gene co-expression network analysis (WGCNA), comprising 277 hub genes. Interestingly, the co-expressed genes that clustered into similar modules exhibited diverse expression tendencies and got annotated to different GO terms at different stages. MapMan analysis revealed that DEGs related to stress signal transduction, detoxification, transcription factor regulation, hormone signaling, and secondary metabolites biosynthesis were universal across the four growth stages. However, DEGs associated with photosynthesis and amino acid metabolism; protein degradation; transport; and RNA transcriptional regulation were uniquely enriched at the V12, VT, R2, and R4 stages, respectively. Our results affirmed that maize drought stress adaptation is a growth-stage-specific response process, and aid in clarifying the fundamental growth-stage-specific mechanisms regulating drought stress responses in maize. Moreover, genes and metabolic pathways identified here can serve as valuable genetic resources or selection targets for further functional validation experiments.

scholarly journals Putative Mechanisms of Drought Tolerance in Maize (Zea mays L.) via Root System Architecture Traits

2019 ◽  
pp. 1-19 ◽  
Author(s):  
A. M. M. Al-Naggar ◽  
M. M. Shafik ◽  
M. O. A. Elsheikh
Keyword(s):  
Water Stress ◽  
Drought Tolerance ◽  
Root System ◽  
Root Architecture ◽  
Dry Weight ◽  
Grain Filling ◽  
Tolerance Index ◽  
Root Branching ◽  
Crown Root ◽  
Drought Tolerant

Identifying maize genotypes with favorable root architecture traits for drought tolerance is prerequisite for initiating a successful breeding program for developing high yielding and drought tolerant varieties of maize. The aims of the present study were: (i) to identify drought tolerant genotypes of maize at flowering and grain filling, (ii) to interpret the correlations between the drought tolerance and root architecture traits and (iii) to identify the putative mechanisms of drought tolerance via root system traits. An experiment was carried out in two years using a split plot design with three replications. The main plots were assigned to three water stress levels, namely: well watering (WW), water stress at flowering (WSF) and water stress at grain filling (WSG), and sub-plots to 22 maize cultivars and populations. Drought tolerance index (DTI) had strong and positive associations with crown root length (CRL), root circumference (RC) and root dry weight (DRW) under both WSF and WSG, a negative correlation with brace root whorls (BW), and positive correlations with crown root number (CN) under WSF and brace root branching (BB) and crown root branching (CB) under WSG. These root traits are therefore considered as putative mechanisms of drought tolerance. The cultivars Pioneer-3444, SC-128, Egaseed-77, SC-10 and TWC-324 showed the most drought tolerant and the highest yielding in a descending order; each had a number of such drought tolerance mechanisms. Further investigation should be conducted to determine the underlying root mechanisms contributing to the selection of water-efficient hybrids of maize.

Screening of Blackgram Genotypes for Drought Tolerance using PEG (Polyethylene Glycol) Induced Drought Stress at Seedling Stage

2021 ◽  
Author(s):  
C. Shobanadevi ◽  
R. Elangaimannan ◽  
K. Vadivel
Keyword(s):  
Polyethylene Glycol ◽  
Drought Stress ◽  
Drought Tolerance ◽  
Growth And Yield ◽  
Growth Stages ◽  
Tolerance Index ◽  
Abiotic Factor ◽  
Drought Tolerance Index ◽  
Germination Indices ◽  
Peg Stress

Background: Drought is one of the abiotic factor. It is considered to be a moderate loss of water. Water is main source involving for all activities of plant growth throughout the crop plants. Seed germination is considered as one of the first and foremost fundamental life stages of a plant, where the success in growth and yield is also depending on this stage. Methods: An experiment was conducted in order to study the effect of different concentrations (i.e., 0, 10, 20 and 30%) of polyethylene glycol (PEG) stress on germination and early growth stages of 28 genotypes of black gram. Different germination indices such as germination percent, radical length, plumule length, along with drought parameters like drought tolerance index was measured. Conclusion: Results showed significant differences among the cultivars at each drought stress level and significant decrease was observed in germination, length of radical and plumule and radical and plumule dry matter parameters, among all the genotypes genotypes Nirmal 7, NRIB 002, MDU 1, VBN 8 and NUL 7 VISWAS showed their efficiency in terms of germination and germination attributes to with stand to the drought conditions. 

Irrigation effects on quality characteristics of durum wheat

2003 ◽  
Vol 83 (2) ◽  
pp. 327-331 ◽  
Author(s):  
M. Güler
Keyword(s):  
Water Stress ◽  
Durum Wheat ◽  
Grain Filling ◽  
Quality Characteristics ◽  
Kernel Weight ◽  
Growth Stages ◽  
Key Words Wheat ◽  
Triticum Durum Desf ◽  
Irrigation Effects

Water stress can affect the quality characteristics of durum wheat (Triticum durum Desf.). The responses of three cultivars of durum wheat to four irrigation regimes [no irrigation or irrigation applied at three growth stages (sowing, jointing, and anthesis)] were evaluated at Ankara, Turkey, from 1993 to 1995. Thousand-kernel weight and test weight increased with irrigation at all three stages, whereas irrigation at sowing and jointing resulted in high pigmentation and protein values. When irrigation was applied at sowing and jointing, but not at anthesis, with water stress occurring only at grain filling, the quality of the grain was positively affected. Key words: Wheat, durum, stress, water quality, grain, irrigation

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