scholarly journals Genetic Dissection of Grain Yield and Agronomic Traits in Maize under Optimum and Low-Nitrogen Stressed Environments

2020 ◽  
Vol 21 (2) ◽  
pp. 543 ◽  
Author(s):  
Berhanu Tadesse Ertiro ◽  
Michael Olsen ◽  
Biswanath Das ◽  
Manje Gowda ◽  
Maryke Labuschagne
Keyword(s):  
Grain Yield ◽  
Agronomic Traits ◽  
Genotyping By Sequencing ◽  
Genetic Dissection ◽  
Common Qtl ◽  
Chromosome Position ◽  
Maize Varieties ◽  
Dh Lines ◽  
Genomic Regions ◽  
Low Nitrogen

Understanding the genetic basis of maize grain yield and other traits under low-nitrogen (N) stressed environments could improve selection efficiency. In this study, five doubled haploid (DH) populations were evaluated under optimum and N-stressed conditions, during the main rainy season and off-season in Kenya and Rwanda, from 2014 to 2015. Identifying the genomic regions associated with grain yield (GY), anthesis date (AD), anthesis-silking interval (ASI), plant height (PH), ear height (EH), ear position (EPO), and leaf senescence (SEN) under optimum and N-stressed environments could facilitate the use of marker-assisted selection to develop N-use-efficient maize varieties. DH lines were genotyped with genotyping by sequencing. A total of 13, 43, 13, 25, 30, 21, and 10 QTL were identified for GY, AD ASI, PH, EH, EPO, and SEN, respectively. For GY, PH, EH, and SEN, the highest number of QTL was found under low-N environments. No common QTL between optimum and low-N stressed conditions were identified for GY and ASI. For secondary traits, there were some common QTL for optimum and low-N conditions. Most QTL conferring tolerance to N stress was on a different chromosome position under optimum conditions.

scholarly journals Trait-QTL-heritability of grain yield and other agronomic traits under low nitrogen conditions in bi-parental maize populations

2021 ◽  
Vol 2 (1) ◽  
pp. 096-116
Author(s):  
Collins Kimutai ◽  
Manje Gowda ◽  
Oliver Kiplagat
Keyword(s):  
Grain Yield ◽  
Complex Traits ◽  
Agronomic Traits ◽  
Complex Nature ◽  
Maize Crop ◽  
Maize Populations ◽  
Solution Mapping ◽  
Genomic Regions ◽  
Low Nitrogen ◽  
Nitrogen Conditions

Limited or low Nitrogen is a wanting abiotic stress in maize mainly in Sub-Sahara Africa, affecting yields and quality development of maize crop. As an approach to getting a breeding solution; mapping of QTLs and understanding the heritability factor can provide useful information and guide for breeders in developing low nitrogen resilient maize. QTL mapping which is a molecular breeding component forms an actual basis in estimation of genomic regions associated to the expression of quantitative traits, and how heritable are such traits. Conducting a selection for Low N-tolerance is challenging due to its complex nature with strong interaction between genotypes and environments; therefore, marker assisted breeding is key to improving such complex traits, but at the same time requires markers associated with the trait of interest. In this study, three bi-parental populations were subjected to either or both low and optimum N conditions to detect and determine the QTLs heritability for grain yield and other agronomic traits. Essential to the study; genotype by environmental interaction, significance and heritability was examined for each population with most traits expressing low (<0.2) and moderate to high heritabilities (0.3>). These QTLs with high heritabilities across environments will be of great value for rapid introgression into maize populations using marker assisted selection approach. The study was a preliminary and therefore require further validation on heritability and fine mapping for them to be useful in MAS.

scholarly journals Meta-QTL and ortho-MQTL analyses identified genomic regions controlling rice yield, yield-related traits and root architecture under water deficit conditions

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Bahman Khahani ◽  
Elahe Tavakol ◽  
Vahid Shariati ◽  
Laura Rossini
Keyword(s):  
Water Deficit ◽  
Root Architecture ◽  
Agronomic Traits ◽  
Heading Date ◽  
Dry Weight ◽  
Genetic Dissection ◽  
Rice Varieties ◽  
Average Confidence ◽  
Stable Qtls ◽  
Genomic Regions

AbstractMeta-QTL (MQTL) analysis is a robust approach for genetic dissection of complex quantitative traits. Rice varieties adapted to non-flooded cultivation are highly desirable in breeding programs due to the water deficit global problem. In order to identify stable QTLs for major agronomic traits under water deficit conditions, we performed a comprehensive MQTL analysis on 563 QTLs from 67 rice populations published from 2001 to 2019. Yield and yield-related traits including grain weight, heading date, plant height, tiller number as well as root architecture-related traits including root dry weight, root length, root number, root thickness, the ratio of deep rooting and plant water content under water deficit condition were investigated. A total of 61 stable MQTLs over different genetic backgrounds and environments were identified. The average confidence interval of MQTLs was considerably refined compared to the initial QTLs, resulted in the identification of some well-known functionally characterized genes and several putative novel CGs for investigated traits. Ortho-MQTL mining based on genomic collinearity between rice and maize allowed identification of five ortho-MQTLs between these two cereals. The results can help breeders to improve yield under water deficit conditions.

scholarly journals Combining Ability Study for Grain Yield and Agronomic Traits of Quality Protein Maize (Zea mays L.) Inbred Lines Adapted to Mid-Altitude Agroecology of Ethiopia

2021 ◽  
Vol 4 (3) ◽  
pp. 286-304
Author(s):  
Lemi Mideksa Yadesa ◽  
Sentayehu Alamerew ◽  
Berhanu Tadesse
Keyword(s):  
Grain Yield ◽  
Combining Ability ◽  
Agronomic Traits ◽  
Inbred Lines ◽  
Quality Protein Maize ◽  
Lattice Design ◽  
Maize Cultivars ◽  
Maize Inbred Lines ◽  
Maize Varieties ◽  
Almost All

In spite of the importance of quality protein maize to alleviate protein deficiency, almost all maize varieties cultivated in Ethiopia are normal maize varieties, which are devoid of lysine and tryptophan. Perusing the combining ability of QPM inbred for grain yield and its components is vital to design appropriate breeding strategies for the development of nutritionally enhanced maize cultivars. A line x tester analysis involving 36 crosses generated by crossing 9  elite maize inbred lines with 4 testers were evaluated for different desirable agronomic traits during the 2019 main season at BNMRC and JARC. The experiment was conducted using alpha lattice design with 3 replications. The objectives were to determine the combining ability of quality protein maize inbred lines, adapted to mid altitude agroecology of Ethiopia for agronomic traits. The crosses were evaluated in alpha lattice design replicated 3 times. Analyses of variances showed significant mean squares due to crosses for almost all the traits studied. GCA mean squares due to lines and testers were significant (P<0.05 or P<0.01) for most studied traits. SCA mean squares were also significant for most attributes across locations. The comparative importance of GCA and SCA variances observed in the current study for most studied traits indicated the preponderance of additive genetic variance in governing these attributes. Only L3 was the best general combiner for grain yield. Inbred line L3, for days to anthesis and L5 for days to silking had negative and significant GCA effects. L5 and L6 displayed negative and significant GCA effects for plant and ear height. Crosses, L2xT4, L3xT4, L4xT4, L5xT2, L6xT3, L7xT2, L9xT1 and L9xT4 were good specific combiners for grain yield. In general, these genotypes help as a source of promising alleles that could be used for forthcoming breeding work in the development of quality protein maize cultivars with desirable traits.

scholarly journals Genome-wide association study for yield and yield related traits under reproductive stage drought in a diverse indica-aus rice panel

2020 ◽  
Author(s):  
Aditi Bhandari ◽  
Nitika Sandhu ◽  
Jérôme Bartholome ◽  
Tuong-Vi Cao-Hamadoun ◽  
Nourollah Ahmadi ◽  
...  
Keyword(s):  
Grain Yield ◽  
Field Experiments ◽  
Genome Wide Association Study ◽  
Agronomic Traits ◽  
Reproductive Stage ◽  
Phenotypic Variance ◽  
Rice Varieties ◽  
Drought Tolerant ◽  
Genome Wide ◽  
Genomic Regions

Abstract Background Reproductive-stage drought stress is a major impediment to rice production in rainfed areas. Conventional and marker-assisted breeding strategies for developing drought-tolerant rice varieties are being optimized by mining and exploiting adaptive traits, genetic diversity; identifying the alleles, and understanding their interactions with genetic backgrounds for their increased contribution to drought tolerance. Field experiments were conducted in this study to identify marker-trait associations (MTAs) involved in response to yield under reproductive-stage (RS) drought. A diverse set of 280 indica-aus accessions was phenotyped for ten agronomic traits including yield and yield-related traits under normal irrigated condition and under two managed reproductive-stage drought environments. The accessions were genotyped with 215,250 single nucleotide polymorphism markers. Results The study identified a total of 219 significant MTAs for 10 traits and candidate gene analysis within a 200kb window centred from GWAS identified SNP peaks detected these MTAs within/ in close proximity to 38 genes, 4 earlier reported major grain yield QTLs and 6 novel QTLs for 7 traits out of the 10. The significant MTAs were mainly located on chromosomes 1, 2, 5, 6, 9, 11 and 12 and the percent phenotypic variance captured for these traits ranged from 5 to 88%. The significant positive correlation of grain yield with yield-related and other agronomic traits except for flowering time, observed under different environments point towards their contribution in improving rice yield under drought. Seven promising accessions were identified for use in future genomics-assisted breeding programs targeting grain yield improvement under drought. Conclusion These results provide a promising insight into the complex genetic architecture of grain yield under reproductive-stage drought in different environments. Validation of major genomic regions reported in the study will enable their effectiveness to develop drought-tolerant varieties following marker-assisted selection as well as to identify genes and understanding the associated physiological mechanisms.

scholarly journals Evaluation of Drought Tolerant Maize Varieties under Drought and Rain-Fed Conditions: A Rainforest Location

2016 ◽  
Vol 8 (7) ◽  
pp. 153
Author(s):  
Abimbola Oluwaranti ◽  
Oluwatosin Temilade Ajani
Keyword(s):  
Grain Yield ◽  
Agronomic Traits ◽  
Drought Tolerant ◽  
Cropping Season ◽  
Strong Positive Relationship ◽  
Maize Varieties ◽  
Ear Height ◽  
The Relationship ◽  
Ear Number

<p>Newly developed drought tolerant maize (<em>Zea mays</em> L.) varieties have been hypothesized to be of different genetic make-ups, hence this study was conducted to evaluate drought-tolerant maize varieties under drought and rain-fed conditions, identify the highest yielding varieties and determine the relationship between agronomic traits and varieties’ yield under these conditions in a rainforest location. Nine drought tolerant varieties of maize and a local check were evaluated during the early part of the early cropping season (March) (Drought) as well as the actual early cropping season (May-June) (Rain-fed) of 2015 at the Teaching and Research Farm (T&amp;RF) of Obafemi Awolowo University, Ile-Ife (7°28'N, 4°33'E and 244 m above sea level). There were significant differences among the two environments for all the traits measured. The performance of the drought tolerant maize varieties is better under the rain-fed condition. The yield performance of all varieties are not significantly different from each other (1.36 tons/ha to 2.75 tons/ha) under drought except EVDT-W 2000 STR C<sub>0</sub> (1.10 tons/ha). All the varieties evaluated under rain-fed condition produce higher grain yield (2-44 tons/ha-3.69 tons/ha) which are not significantly different each other. All the yield components except ear height and length had a strong positive relationship with grain yield under drought while only ear number and weight had relationship with yield under rain-fed condition. In conclusion, among the drought tolerant maize varieties, EVDT-W 2000 STR C<sub>0</sub> need further improvements to drought. Furthermore, ear weight can be used to select parents for the development of drought tolerant maize varieties in this agro-ecology.</p>

scholarly journals Evaluating Maize Genotype Performance under Low Nitrogen Conditions Using RGB UAV Phenotyping Techniques

Sensors ◽  
2019 ◽  
Vol 19 (8) ◽  
pp. 1815 ◽  
Author(s):  
Ma. Luisa Buchaillot ◽  
Adrian Gracia-Romero ◽  
Omar Vergara-Diaz ◽  
Mainassara A. Zaman-Allah ◽  
Amsal Tarekegne ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Grain Yield ◽  
Vegetation Index ◽  
Yield Potential ◽  
Plant Phenotyping ◽  
Phenotypic Traits ◽  
Optimal Conditions ◽  
Maize Varieties ◽  
Low Nitrogen ◽  
Nitrogen Conditions

Maize is the most cultivated cereal in Africa in terms of land area and production, but low soil nitrogen availability often constrains yields. Developing new maize varieties with high and reliable yields using traditional crop breeding techniques in field conditions can be slow and costly. Remote sensing has become an important tool in the modernization of field-based high-throughput plant phenotyping (HTPP), providing faster gains towards the improvement of yield potential and adaptation to abiotic and biotic limiting conditions. We evaluated the performance of a set of remote sensing indices derived from red–green–blue (RGB) images along with field-based multispectral normalized difference vegetation index (NDVI) and leaf chlorophyll content (SPAD values) as phenotypic traits for assessing maize performance under managed low-nitrogen conditions. HTPP measurements were conducted from the ground and from an unmanned aerial vehicle (UAV). For the ground-level RGB indices, the strongest correlations to yield were observed with hue, greener green area (GGA), and a newly developed RGB HTPP index, NDLab (normalized difference Commission Internationale de I´Edairage (CIE)Lab index), while GGA and crop senescence index (CSI) correlated better with grain yield from the UAV. Regarding ground sensors, SPAD exhibited the closest correlation with grain yield, notably increasing in its correlation when measured in the vegetative stage. Additionally, we evaluated how different HTPP indices contributed to the explanation of yield in combination with agronomic data, such as anthesis silking interval (ASI), anthesis date (AD), and plant height (PH). Multivariate regression models, including RGB indices (R2 > 0.60), outperformed other models using only agronomic parameters or field sensors (R2 > 0.50), reinforcing RGB HTPP’s potential to improve yield assessments. Finally, we compared the low-N results to the same panel of 64 maize genotypes grown under optimal conditions, noting that only 11% of the total genotypes appeared in the highest yield producing quartile for both trials. Furthermore, we calculated the grain yield loss index (GYLI) for each genotype, which showed a large range of variability, suggesting that low-N performance is not necessarily exclusive of high productivity in optimal conditions.

scholarly journals Combining Ability and Heterosis for Agronomic Traits, Husk and Cob Pigment Concentration of Maize

Agriculture ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 510
Author(s):  
Ponsawan Khamphasan ◽  
Khomsorn Lomthaisong ◽  
Bhornchai Harakotr ◽  
Marvin Paul Scott ◽  
Kamol Lertrat ◽  
...  
Keyword(s):  
Grain Yield ◽  
Combining Ability ◽  
Agronomic Traits ◽  
F1 Hybrids ◽  
Trolox Equivalent Antioxidant Capacity ◽  
Total Phenolic ◽  
Anthocyanin Content ◽  
Gene Effects ◽  
Total Anthocyanin ◽  
Maize Varieties

The objective of this study was to identify the maize inbred lines with good general combining ability (GCA), good specific combining ability (SCA), high heterosis for yield and phytochemicals, and the crosses with high yield of yellow kernels and high anthocyanin content in cobs and husk, which was probably related to the high antioxidant activity. The parental lines including five unpigmented females and five pigmented males were crossed in North Carolina design II. The parents, the resulting 25 hybrids, and 5 controls were evaluated at two locations in the dry season of 2016/2017. Additive and non-additive gene effects controlled the inheritance of grain yield, agronomic traits, and phytochemicals. KKU–PFC2 and KKU–PFC4 had the highest GCA effects for phytochemical traits in husk and cob, whereas Takfa1 and Takfa3 were good combiners for grain yield. F1 hybrids had significantly higher total anthocyanin content (TAC), total phenolic content (TPC), (2,2-diphenyl-1-picrylhydrazyl) (DPPH), and trolox equivalent antioxidant capacity (TEAC) in husk and cob than pigmented control cultivars. The hybrids superior for individual traits were identified, but the experiment was not able to identify superior hybrids for multiple traits. The Takfa3 × KKU–PFC5 and NakhonSuwan2 × KKU-PFC4 had the highest anthocyanin in husk and cobs, respectively. The breeding strategies to develop maize varieties with high anthocyanins and normal yellow kernels and utilization of the hybrids are discussed.

Genetic analysis of low-n traits in maize (Zea mays L) using triple test cross

2021 ◽  
Vol 20 (1) ◽  
pp. 17-28
Author(s):  
M.S. Afolabi ◽  
G.O. Agbowuro ◽  
A.E Salami ◽  
M.O. Akoroda
Keyword(s):  
Grain Yield ◽  
Plant Height ◽  
Inbred Lines ◽  
Triple Test Cross ◽  
Test Cross ◽  
Triple Test ◽  
Maize Varieties ◽  
Maize Variety ◽  
Ear Height ◽  
Low Nitrogen

Low-N maize variety is developed for its ability to tolerate low nitrogen soil environment. This experiment was conducted to study the genetic implication of Low-N maize variety for grain yield and related traits under low nitrogen soil conditions triple test cross analysis. Inbred lines used for the study were generated from twelve low nitrogen tolerance open pollinated maize varieties after six generations of selfing. Two inbred lines along with their F1 were used as testers for ten inbred lines in a triple test cross pattern to generate 30 crosses. The 30 crosses, their parents and the testers to State University, Ado-Ekiti during 2017 planting season. The experimental design was a Randomized Complete Block Design (RCBD). Data were collected on plant height, ear height, days to 50% anthesis, days to 50% silking, incidence of curvularia leaf spot, blight, plant aspect, ear aspect, ear rot, stay green, cob per plant, ear weight, grain moisture content and grain yield. All data were subjected to analysis of variance and complete genetic estimates. Additive and dominants were significant (P < 0.05) for all traits; however, epitasis estimates were not significant for all the traits tested. The degree of dominance component indicated partial dominance for all the traits. Correlation coefficients for days to 50% anthesis and 50% silking, plant height, ear height, number of cobs per plant and grain yield were positive and significant (P < 0.05). Since both additive and dominance gene actions were important for low-N traits, the use of reciprocal recurrent selection procedure can be adopted in incorporating the trait into elite maize varieties.

scholarly journals Identification of quantitative trait loci for agronomic traits contributed by a barley (Hordeum vulgare) Mediterranean landrace

2016 ◽  
Vol 67 (1) ◽  
pp. 37 ◽  
Author(s):  
Ridha Boudiar ◽  
Ana M. Casas ◽  
Carlos P. Cantalapiedra ◽  
M. Pilar Gracia ◽  
Ernesto Igartua
Keyword(s):  
Quantitative Trait Loci ◽  
Hordeum Vulgare ◽  
Grain Yield ◽  
Quantitative Trait ◽  
Agronomic Traits ◽  
Genotyping By Sequencing ◽  
Kernel Weight ◽  
Nucleotide Polymorphisms ◽  
Hordeum Vulgare L ◽  
Trait Loci

Some Spanish barley (Hordeum vulgare L.) landraces perform better than modern cultivars at low-production sites. The objective of this study was to identify favourable quantitative trait loci (QTLs) for interesting agronomic traits contributed by the landrace SBCC073. To achieve this objective, a population of 100 BC1F5 lines was derived from the cross between the elite cultivar Orria, with high productivity, and the Spanish landrace SBCC073, which was the best performer in low-production trials. The population was evaluated in field trials for 3 years (2011, 2013, and 2014) in Zaragoza, Spain. The population was genotyped with a DArTseq genotyping-by-sequencing assay. A genetic linkage map was developed by using markers of four flowering-time genes and 1227 single-nucleotide polymorphisms of good quality. The genetic map resulted in 11 linkage groups, covering a total distance of 871.1 cM. Five QTLs for grain yield were detected on 2H.1, 4H, 5H and 6H.2. Alleles from SBCC073 contributed to increased yield in three of them. A region at the end of chromosome 5H contains favourable alleles for early vigour, higher grain yield and earlier flowering, all derived from SBCC073. Alleles from Orria contributed to increasing grain yield and simultaneously to reducing plant height on the same region of 6H.2, and to increasing 1000-kernel weight on chromosomes 3H and 5H.

scholarly journals Evaluation of Hybrid and OPV Maize Varieties for Grain Yield and Agronomic Attributes under Farmer's Field Conditions at Dukuchhap

2014 ◽  
Vol 9 ◽  
pp. 17-20 ◽  
Author(s):  
Min N. Paudel
Keyword(s):  
Grain Yield ◽  
Field Experiments ◽  
Agronomic Traits ◽  
Grain Weight ◽  
Yield Attributes ◽  
Bivariate Correlation ◽  
Maize Varieties ◽  
Ear Height ◽  
Study Support ◽  
Stalk Lodging

Field experiments were conducted during two consecutive years 2006 and 2007 in full season of maize (May-Sep) at Dukuchhap, Lalitpur to find out impact of growing hybrid and OPV maize in different rows combinations with respect to their pure stands in same environment of growing and to sort out non-lodging maize varieties. The experiments consisted of an open pollinated variety (OPV) 'Deuti' and hybrid 'Gaurab' in different row combinations (50% hybrid + 50% OPV, 75% hybrid + 25% OPV, 75% OPV + 25% hybrid plus their pure stands). The results showed that Gaurab (yellow, flint type) and Deuti (white, semi- flint type, selected from CIMMYT's material ZM 621) did not vary significantly in grain yield and yield components. There was no effect of mixed row culture between the OPV and hybrid for grain yield and yield attributes. A bivariate correlation coefficient between agronomic traits and ear traits indicated that there was a positive relation among these traits. However, a positive and highly significant (r = 0.766**) relationship between ear fill and ear length was observed while a very weak relation (r = 0.096*) between grain weight/ear and ear height was also noticed suggesting taller the ear height lower the grain yield/ear and vice versa. The findings of the study support that plant height and ear height were weakly related with other ear traits; nevertheless, these were highly related to grain weight/per plant. To cope with stalk lodging problem and to attain higher grain yield these varieties are equally potential and recommended to grow under Dukuchhap conditions.Nepal Agric. Res. J. Vol. 9, 2009, pp. 17-20  DOI: http://dx.doi.org/10.3126/narj.v9i0.11637

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