Grain Yield In Bread Wheat Research Articles

Identification of traits for the improvement of grain yield in bread wheat under nitrogen stress and non-stress conditions

Abstract Correlation, path coefficient and step-wise regression analyses were used to identify important traits that affect grain yield in bread wheat. Thirty bread wheat varieties were field tested under with (N+) and without nitrogen (N0) conditions at New Developmental Research Farm, The University of Agriculture, Peshawar-Pakistan. Experimental materials were planted in randomized complete block (RCB) design with three replications. Correlation analysis revealed significant positive association of grain yield with number of spikes m-2, biological yield and harvest index under both production systems. For the 1000-grain weight, positive association was observed under N+ condition only. Furthermore, path coefficient analysis confirmed the true relationship of harvest index, biological yield, number of spikes m-2, and 1000-grain weight with grain yield in wheat. Similarly, step-wise regression analysis identified spikes m-2, grains spike-1, 1000-grain weight, harvest index and biological yield as important traits affecting grain yield in wheat under respective production system. Overall, on the basis of current statistical procedures spikes m-2, grains spike-1, 1000 grain weight, harvest index and biological yield needs due weightage in breeding program for further improvement in grain yield of bread wheat. Keywords: Biological Yield; Correlation; Path analysis; Step-wise regression http://dx.doi.org/10.19045/bspab.2019.80011

AMMI and GGE biplot analysis of grain yield of bread wheat (Triticum aestivum L.) genotypes at moisture deficit environment of Wollo, Ethiopia

Twenty-two bread wheat varieties were tested at six locations of eastern Amhara region. The experiment was laid-out using Randomized Complete Block (RCB) design and replicated three times with the objective of estimating the magnitude of Genotype by Environment (GE) interactions for grain yield and stability of bread wheat genotypes. Individual environment and combined analysis of variance were carried out using Genstat software 18th edition and Least Significant Difference (LSD) was employed to separate means. Combined ANOVA for grain yield showed significant difference among genotypes, environments, and GE interactions. Genotypes G1, G9 and G16 out-smarted in grain yield, providing mean grain yield of 3.60, 3.56, and 3.55 tha-1, respectively. The stability was measured by AMMI and GGE biplot. AMMI-1 select most adapted genotypes such as G9 and G16 for E3 and G17 for E1. G12, G6, G3, G19, G7 and G11 genotypes were suitable for all environments. AMMI-2 biplot showed E1, E5 and E6 contributed large interaction effects while E2, E3 and E4 contributed small interaction effects. GGE biplot identify G9, G16 and G19 for E1, E3, E6 and E5 and G17, G21, G14 and G15 for E1 and E4. G6, G12 and G1 genotypes were good for all environments. Thus, due attention should be given while selecting bread wheat genotypes for the target environments.

English

Crop models are highly useful for simulating crop and soil processes in response to variations in climate and crop management. However, well estimated crop genetic coefficients are required. So the purpose of this study is to calibrate and evaluate the performance of CERES-wheat model and to simulate the climate change impacts on phonological stages and grain yield of bread wheat (Tay and Senkegna varieties) in the study area. Observed climate data from National Meteorological Agency of Ethiopia from 1983 to 2015 and future climate from Climate Research Programme’s Fifth Coupled Model Intercomparison Project (CMIP5) database across 20 Global Circulation Models for Representative Concentration Pathway (RCP4.5 and 8.5) emission scenarios in the time horizon of early-term (2010-2039), mid-century (2040-2069) and end-century (2070-2100) were used. Crop and soil data were obtained from Adet Agricultural Research Center. Decision Support System for Agro-technology Transfer (DSSAT) crop model was employed. There was strong agreement between the simulated and observed values with R2 being 96, 79 and 79% for days to anthesis, grain yield and days to maturity, respectively for Tay wheat variety while 75% for days to anthesis, 92% for grain yield, and 75% for days to maturity of Senkegna bread wheat variety. On the other hand, during model validation, the goodness of fits (R2) was 86% for anthesis day, 70% for grain yield and 96% for physiological maturity days of Tay wheat variety. Similarly for Senkegna bread wheat variety, R2 was 89, 82 and 75% for anthesis day, grain yield, and physiological maturity days, respectively. The yield of both bread wheat varieties showed increase except in 2080s under RCP4.5 relative to the baseline. However, days to flowering and to maturity showed decreased in each time slice under both RCPs. Key words: Calibration, validation, crop model, wheat, Ethiopia, East Africa.

Review on the Effect of Seed Source and Size on Grain Yield of Bread Wheat (Tritium Aestivum L.)

Review on the Effect of Seed Source and Size on Grain Yield of Bread Wheat (Tritium Aestivum L.)

Extending the duration of the ear construction phase to increase grain yield of bread wheat

We tested the hypothesis that lengthening the duration between the terminal spikelet stage of development and anthesis (referred to here as the construction-phase duration, CPD) will increase yield per unit area in wheat (Triticum aestivum L.). Field experiments were undertaken at 17 sites across the high-rainfall zone of south-eastern and Western Australia in 2014 and 2015. In total, 205 wheat genotypes were grown. Genetic material included a set of near-isogenic lines (NILs) varying in photoperiod and vernalisation alleles; commercial wheat cultivars and breeding lines; and lines selected from the Multiparent Advanced Generation Inter Cross population. As such, this is the only comprehensive dataset in which the effect of variation in CPD on grain yield in field plots has been evaluated in diverse field environments. Within an optimum anthesis window of 10 days, longer CPD significantly increased grain yield by >11% at two sites and tended to increase grain yield at another 11 sites (not statistically significant). The average yield increase across these sites was 5.5%. There was no consistent trend whereby a specific yield component was responsible for the increase across sites. We suggest that CPD can be extended by genetic selection and by sacrificing some of the vegetative period without any detriment to grain yield. We also found that CPD is increased by extending the duration from sowing to flowering through earlier sowing, which may be associated with increased yields in some environments. We conclude that, for the same anthesis date, a longer CPD may be beneficial in moderately favourable rainfed environments with a relatively even distribution of rainfall. We explore the basis of these relationships and implications for growers and plant breeders.

Prospects and Challenges of Applied Genomic Selection-A New Paradigm in Breeding for Grain Yield in Bread Wheat.

Genomic selection (GS) has been promising for increasing genetic gains in several species. Therefore, we evaluated the potential integration of GS for grain yield (GY) in bread wheat (Triticum aestivum L.) in CIMMYT’s elite yield trial nurseries. We observed that the genomic prediction accuracies within nurseries (0.44 and 0.35) were substantially higher than across-nursery accuracies (0.15 and 0.05) for GY evaluated in the bed and flat planting systems, respectively. The accuracies from using only a subset of 251 genotyping-by-sequencing markers were comparable to the accuracies using all 2038 markers. We also used the item-based collaborative filtering approach for incorporating other related traits in predicting GY and observed that it outperformed genomic predictions across nurseries, but was less predictive when trait correlations with GY were low. Furthermore, we compared GS and phenotypic selections (PS) and observed that at a selection intensity of 0.5, GS could select a maximum of 70.9 and 61.5% of the top lines and discard 71.5 and 60.5% of the poor lines selected or discarded by PS within and across nurseries, respectively. Comparisons of GS and pedigree-based predictions revealed that the advantage of GS over the pedigree was moderate in populations without full-sibs. However, GS was less advantageous for within-family selections in elite families with few full-sibs and minimal Mendelian sampling variance. Overall, our results demonstrate the importance of applying GS for GY at the appropriate stage of the breeding cycle, and we speculate that gains can be maximized if it is implemented in early-generation within-family selections.

Exogenous sodium nitroprusside increases antioxidative potential and grain yield of bread wheat exposed to cadmium

Exogenous sodium nitroprusside increases antioxidative potential and grain yield of bread wheat exposed to cadmium

Estimation of General and Specific Combining Abilities of Morphological Traits and Grain Yield in Bread Wheat

Estimation of General and Specific Combining Abilities of Morphological Traits and Grain Yield in Bread Wheat

Global QTL Analysis Identifies Genomic Regions on Chromosomes 4A and 4B Harboring Stable Loci for Yield-Related Traits Across Different Environments in Wheat (Triticum aestivum L.).

Major advances in wheat production are needed to address global food insecurity under future climate conditions, such as high temperatures. The grain yield of bread wheat (Triticum aestivum L.) is a quantitatively inherited complex trait that is strongly influenced by interacting genetic and environmental factors. Here, we conducted global QTL analysis for five yield-related traits, including spike yield, yield components and plant height (PH), in the Nongda3338/Jingdong6 doubled haploid (DH) population using a high-density SNP and SSR-based genetic map. A total of 12 major genomic regions with stable QTL controlling yield-related traits were detected on chromosomes 1B, 2A, 2B, 2D, 3A, 4A, 4B, 4D, 5A, 6A, and 7A across 12 different field trials with timely sown (normal) and late sown (heat stress) conditions. Co-location of yield components revealed significant tradeoffs between thousand grain weight (TGW) and grain number per spike (GNS) on chromosome 4A. Dissection of a “QTL-hotspot” region for grain weight on chromosome 4B was helpful in marker-assisted selection (MAS) breeding. Moreover, this study identified a novel QTL for heat susceptibility index of thousand grain weight (HSITGW) on chromosome 4BL that explains approximately 10% of phenotypic variation. QPh.cau-4B.2, QPh.cau-4D.1 and QPh.cau-2D.3 were coincident with the dwarfing genes Rht1, Rht2, and Rht8, and haplotype analysis revealed their pleiotropic architecture with yield components. Overall, our findings will be useful for elucidating the genetic architecture of yield-related traits and developing new wheat varieties with high and stable yield.

Estimates of genetic components and regression analysis for grain yield and various morphological traits in bread wheat (Triticum aestivum L.)

The present study was conducted to estimate the gentic components and regression analysis for grain yield and various morphological traits in bread wheat involving 10 parents and their 45 F1s (half diallel) during 2012- 13 and 2013-14. Significant additive (D) and dominance (H1) variance for the traits indicated that expression of these traits is control by both additive and dominance gene action. Average degree of dominance (H1/D)1/2 were more than unity for the traits (peduncle length, flag leaf area, productive tillers, biological yield, grain yield, harvest index) indicating the preponderance of over dominance gene action. The estimates of h2 were positive and significant for days to ear emergence, peduncle length, productive tillers, biological yield and grain yield indicated dominance of genetic components in F1s. Positive and significant values of F were estimated for days to ear emergence, days to 50% flowering, spike length, flag leaf area and grain yield in F1s indicating the preponderance of dominance and positive genes in the parents involved. The theoretical value (0.25) of (H2/4H1) for all the traits indicated asymmetrical distribution of positive and negative genes. The proportion of dominant and recessive alleles indicated presence of dominant alleles in the parents. The traits showing more than 30% narrow sanse heritability could be rewarding for further improvement in grain yield in bread wheat. Regression analysis indicated that the traits (days to ear emergence, days to 50% flowering, peduncle length, flag leaf area, productive tillers, harvest index, biological yield and grain yield) control by over dominance type of gene action. The parent RAJ 4246 contained maximum dominant genes for days to ear emergence and days to 50% flowering; HD 2733 for spike length and flag leaf area and HD 2824 for productive tillers, biological yield and grain yield used as donors in multiple traits breeding programme to develop high yielding wheat genotypes.

Assessment of Heritable Variation and Best Combining Genotypes for Grain Yield and Its Attributes in Bread Wheat

Grain yield in wheat is the resultant of several plant attributes. It is very important to assess heritable variation involved in the inheritance of these attributes in addition to find the best combining genotypes. For this purpose, the present study involving 5 × 5 full diallel analysis was performed. Twenty F1 hybrids along with their parents (9797, 9801, 9802, Chakwal-50 and Chakwal-86) were planted in field using randomized complete block design (RCBD) with three replications in the research area of Department of Plant Breeding and Genetics, University of Agriculture, Faisalabad during 2015-2016. Plant characters like plant height, flag leaf area, spike length, No. of fertile tillers per plant, No. of grains per spike, No. of spikelets per spike, 1000 grain weight and grain yield per plant were studied in this experiment. Mean squares due to general combining ability (GCA) were highly significant for all the traits except for spike length for which GCA effects were significant. Mean squares due to specific combining ability (SCA) and reciprocal combining ability (RCA) were highly significant for all the characters studied. GCA variance was higher than the SCA variance for spike length and No. of grains per spike exhibiting the predominant role of additive genetic variation in the inheritance of these traits. However, for the characters like plant height, flag leaf area, No. of fertile tillers per plant, No. of spikelets per spike, 1000 grain weight and grain yield per plant, the value of SCA variance was higher than the value of GCA variance showing non additive gene action for these traits. The variety Chakwal-50 proved to be the best general combiner for plant height, spike length, No. of spikelets per spike, No. of grains per spike and grain yield per plant. The cross, 9802 × Chakwal-86 was the best specific combination for grain yield and most of the yield attributes. The good general and specific combiners are important breeding resources for the initiation of future wheat breeding programmes aimed at enhancement of grain yield in bread wheat.

Foliar application of selenium increases fertility and grain yield in bread wheat under contrasting water availability regimes

The study was conducted to assess whether selenium (Se) application modulates fertility to alter grain yield in bread wheat grown under different moisture regimes. Seeds of wheat cultivar Millat-2011 were sown in the plots using a randomized complete block design with three replicates per treatment. After germination, the plants were exposed to six moisture regimes, viz. no irrigation after germination, irrigation at boot stage, irrigations at boot and grain-filling stages, irrigations at crown root, boot and grain-filling stages, irrigations at crown root, boot, heading and grain-filling stages and irrigations at crown root, stem elongation, boot, heading and grain-filling stages. At the heading stage, foliar spray of sodium selenate (0, 2 and 4 mg Se L−1) was done. Withholding water at early growth stages significantly increased oxidative stress and decreased growth and grain yield. Irrespective of moisture regimes, foliar application of Se (2 mg L−1) decreased oxidative stress, modulated photosynthetic pigments and fertility and increased grain yield in wheat. The Se-mediated increase in grain yield was attributed to the increase in chlorophyll and ascorbic acid contents and fertility coupled with decrease of oxidative stress under different moisture regimes. The results could be helpful to manage wheat production in the semi-arid environments.

Evaluation of Synergistic Effect Organic and Inorganic Fertilizing System on Grain Yield of Bread Wheat (Triticum aestivum L.) at Southern Tigray, Northern Ethiopia

Study on the integrated effect of organic and chemical fertilizer levels on bread wheat was conducted in 2013 cropping season at high lands of Adi-golo and Mekan districts of Tigray, Ethiopia with the objective of determining the optimum integration of organic and inorganic fertilization for bread wheat production. The field experiment consists four level of N/P2O5 (0/0, 23/23, 46/46 and 69/69 kg ha-1) and five level of farmyard manure (0, 4, 6, 8 and 10 t ha- 1) arranged in factorial RCBD with three replications. Organic and chemical fertilizer applications had significant (P<0.05) effect on grain yield in the sites. Higher grain yield (5.04 and 2.19 t ha-1) with acceptable marginal of rate return (MRR=1228.9 and 2788.9%) were obtained in the combined application of 46/46 N/P205 kg ha-1+6 t ha-1 farmyard manure and 46/46 N/P2O5 kg ha-1+10 t ha-1 farmyard manure at Adi-golo and Mekan areas respectively. Combined applications of organic and chemical fertilizers are more effective than sole application of organic or chemical fertilizers for sustainable Wheat and soil productivity enhancement.

The Expression of TaRca2-α Gene Associated with Net Photosynthesis Rate, Biomass and Grain Yield in Bread Wheat (Triticum aestivum L.) under Field Conditions.

Improvement in activation of Rubisco by Rubisco activase can potentially enhance CO2 assimilation and photosynthetic efficiency in plants. The three homoeologous copies of TaRca2-α were identified on chromosomes 4AL, 4BS and 4DS (TaRca2-α-4AL, TaRca2-α-4BS, and TaRca2-α-4DS) in bread wheat. Expression patterns of the three copies at heading (Z55), anthesis (Z67) and grain-filling (Z73) stages were investigated through qRT-PCR analyses in a panel of 59 bread wheat genotypes and their effects on net photosynthesis rate (Pn), biomass plant-1 (BMPP) and grain yield plant-1 (GYPP) were further explored. Different but similar expression patterns were observed for the three copies of TaRca2-α at the three growth stages with highest expression at grain-filling stage. TaRca2-α-4BS expressed higher at the three stages than TaRca2-α-4AL and TaRca2-α-4DS. The 59 genotypes could be clustered into three groups as high (7 genotypes), intermediate (41 genotypes) and low (11 genotypes) expression based on the expression of the three copies of TaRca2-α at three growth stages. Significant variations (P<0.01) were observed among the three groups of bread wheat genotypes for Pn, BMPP and GYPP. Generally, the genotypes with higher TaRca2-α expression also showed higher values for Pn, BMPP and GYPP. The expressions of the three copies of TaRca2-α at heading, anthesis and grain-filling stages were positively correlated with Pn, BMPP and GYPP (P<0.01) with stronger association for TaRca2-α-4BS at grain-filling stage. These results revealed that the expression of TaRca2-α contribute substantially to Pn, BMPP and GYPP, and suggested that manipulating TaRca-α expression may efficiently improve Pn, BMPP and GYPP in bread wheat and detecting TaRca-α expression levels with emphasis on TaRca2-α-4BS may be a positive strategy for selection in improving photosynthetic efficiency and grain yield of bread wheat.

Impact of different crop rotations and tillage systems on weed infestation and productivity of bread wheat

Crop rotation and tillage systems have important implications for weed infestation and crop productivity. In this study, five tillage systems viz. zero tillage (ZT), conventional tillage (CT), deep tillage (DT), bed sowing (60/30 cm with four rows; BS1) and bed sowing (90/45 cm with six rows; BS2) were evaluated in five different crop rotations viz. fallow-wheat (FW), rice-wheat (RW), cotton-wheat (CW), mungbean-wheat (MW) and sorghum-wheat (SW) for their effect on weed infestation and productivity of bread wheat. Interaction between different tillage practices and cropping systems had significant effect on density and dry biomass of total, broadleaved and grass weeds, agronomic and yield-related traits, and grain yield of bread wheat. The un-disturbed soils (ZT) under fallow-wheat or mungbean-wheat rotations favoured the weed prevalence (a total weed dry biomass of 72.4–109.6 and 105.6–112.1 g m−2 in first and second year, respectively). Contrary to this, the disturbed soils (CT, DT, BS1 and BS2) had less weed infestation with either of the rotations (a total weed biomass of 0.4–7.1 and 1.1–5.4 g m−2 in first and second year, respectively). Sorghum-wheat rotation had strong suppressive effect on weed infestation in all tillage systems. The impact of crop rotation was more visible during second year of experimentation. Bed sown wheat (BS1 and BS2) in mungbean-wheat rotation had the highest wheat grain yield (6.30–6.47 t ha−1) compared to other tillage systems in different crop rotation combinations.

Evaluation of Grain Yield of Bread Wheat (Triticum aestivum L.) Promising Lines and Detection of Yield Related Agro-Morphological Traits under Terminal Moisture Stress

Evaluation of Grain Yield of Bread Wheat (Triticum aestivum L.) Promising Lines and Detection of Yield Related Agro-Morphological Traits under Terminal Moisture Stress

Evaluation of Grain Yield and Quality Traits of Bread Wheat Genotypes Cultivated in Northwest Turkey

ABSTRACTA study was performed to evaluate the effects of environment (E) and genotype (G) × E interactions (GGE) for quality traits and grain yield in bread wheat (Triticum aestivum L.). ANOVA and GGE biplots were used to assess quality performance and stability in 36 genotypes of bread wheat through a three‐location trial over two cropping seasons in the Thrace Region of Turkey. The 36 wheat genotypes used were classified into eight different groups, including landraces, 1960s, 1970s, 1980s, 1990s, 2000s, and advanced lines. The data showed a wide range of variation for milling quality parameters with regard to gluten quantity and quality, as well as for grain yield. Genotypes, location, and year, in this order, contributed to this diversity. Remarkably, all the traits except grain protein content showed a larger genotype effect than location (L) effect; the interaction G × L was usually more important than the G × Y. Genotypic and location components markedly exceeded G × L and Y × L for all variables, with the exception of grain yield, in which the G × Y effect was greater than locations according to ANOVA analysis. Noticeable continuous progress (53%) was observed in genetic grain yield during the last 60 yr without limiting wheat quality. GGE biplot analysis found that, on average, the biplots accounted for 80 to 85% of G and G × E variation present. Krasunia and Sagittario were the best genotypes (best performance and higher stability) of the study based on the traits evaluated.

Correlation coefficients, stepwise regression and path analysis of grain yield in bread wheat (Triticum aestivum L.) cultivars

Correlation coefficients, stepwise regression and path analysis of grain yield in bread wheat (<i>Triticum aestivum</i> L.) cultivars

Mapping a major QTL for hairy leaf sheath introgressed from Aegilops tauschii and its association with enhanced grain yield in bread wheat

Aegilops tauschii, the diploid D genome progenitor of the hexaploid wheat, has been used to improve modern common wheat by creating synthetic hexaploid wheat (SHW) as a bridging mechanism for wheat breeding. Most Ae. tauschii accessions have hairiness on the leaf sheath, whereas the hexaploid common wheat is usually glabrous. In this study a major QTL for leaf sheath hairiness (LSH) was detected on the long arm of chromosome 4D in two recombinant inbred line (RIL) populations produced from SHW-derived cultivar Chuanmai 42. The QTL peak was flanked by markers Xbarc48 and Xbarc1183/D_GB5Y7FA01AGCKH_224, and explained more than 75 % of the phenotypic variation. The QTL allele for LSH was contributed by Chuanmai 42, and originated from Ae. tauschii. In both RIL populations the QTL allele producing hairy leaf sheath was significantly and positively associated with increased grain yield, grain weight and grain weight per spike. Moreover, most Chuanmai 42-derived cultivars have inherited the hairy leaf sheath character. These findings suggest that the hairy leaf sheath gene in Chuanmai 42 can be applied in marker-assisted selection (MAS) as a morphologically selectable marker in breeding for high yield.

Evaluation of Some Wheat Hybrids under Normal and Heat Stress Conditions

Heat shocks at anthesis are one of the major limitations in wheat productivity in many countries worldwide including Pakistan. Present investigations were designed to battle out this calamity which may further be exploited in breeding heat tolerant cultivars. Seven parents including tolerant, moderately tolerant and susceptible but high yielders were utilized for this purpose and later hybridized in a 7 ×7 diallel fashion. Analysis of variance revealed significant variability for all the parameters studied. Highest value of negative and desirable significant heterosis and heterobeltiosis for plant height was shown by the cross combinations Weebli-1 × Uqab-2000, Inqilab-91 × Shalimar-88 under normal conditions and under stress by the hybrids Uqab-2000 × Weebli-1, Shalimar-88 × Maya/Pavon. Maximum positive heterosis for tillers per plant was recorded by the cross combination Shalimar-88 × Chenab-2000 (12.04%) and maximum positive and highly significant heterobeltiosis was recorded by the cross combination Shalimar-88 × Chenab-2000 (11.46%). Under stress for tillers per plant none of the crosses showed positive estimates. Maximum positive heterosis for 100- grain weight was shown by the cross combination Chenab-2000 × Inqilab-91 (28.22%). Maximum positive heterosis under stress for 100-grain weight was shown by the cross Inqilab-91 × Weebli-1 (23.35%) followed by Chenab-2000 × Inqilab-91 (22.22%). Maximum positive heterosis for grain yield under normal conditions was manifested by the cross combinations Uqab-2000 × Punjab-85 (28.70%) and under stress maximum positive heterosis was recorded by cross combination Shalimar-88 × Uqab-2000 (27.02%). The results of heterosis and heterobeltiosis estimation revealed that the hybrid vigor is available in the current experiment for all the traits and selection of desirable hybrids is the best way to improve the grain yield of bread wheat. Many cross combinations in the current studies may be utilized following pedigree or bulk method to develop heat tolerant wheat varieties because of their ability to perform well under normal and heat stress conditions.