Elite Wheat Genotypes Research Articles

Performance and Stability of Elite Wheat Genotypes under Irrigated, Heat Stress and Heat Drought Environment

Performance and Stability of Elite Wheat Genotypes under Irrigated, Heat Stress and Heat Drought Environment

Phenotypic Correlation, Path Analysis, and Quantitative Trait-Based Selection of Elite Wheat Genotypes Under Heat Stress Conditions in The Terai Region of Nepal

Phenotypic Correlation, Path Analysis, and Quantitative Trait-Based Selection of Elite Wheat Genotypes Under Heat Stress Conditions in The Terai Region of Nepal

Impact of terminal heat stress on performance of Nepalese wheat (Triticum aestivum L.) genotypes

Heat stress has been a major abiotic stress that has been a key factor for poor production and the productivity of wheat. To understand the impact of heat stress and to evaluate the performance and stability of elite wheat genotypes under irrigated and heat stress environment, a field experiment was conducted under Alpha lattice design at the Institute of Agriculture and Animal Science, Bhairahawa, Rupandehi, Nepal from 2019-2023 comprising 20 elite wheat genotypes collected from Nepal Agriculture Research Council. The combined analysis of variance showed, heat stress had the significant impact on all the traits evaluated with a 29% yield reduction under heat stress condition as compared to irrigated. NL 1368 (21.5%) and NL 1386 (41.4%) had the least and highest yield reduction under heat stress environment as compared to irrigated. BL 4919 was the highest yielding wheat genotype under both irrigated (4287.9 kg/ha) and heat stress environment (2905.4 kg/ha). WWW model revealed, NL 1387 was the most stable wheat genotypes while BL 4919 and NL 1350 were the most adaptable genotypes under irrigated and heat stress environment. Hence, these selected adaptive and stable genotypes should be promoted in the wheat improvement program as a parent material for heat stress breeding.

Trait Based Selection of Elite Wheat Genotypes under Irrigated, Heat Stress, and Heat Drought Conditions

Environmental factors affects yield and yield-attributing parameters of wheat. To explore direct and indirect association and to identify the most appropriate trait for trait based selection of elite wheat genotypes under irrigated, heat stress and heat drought conditions, correlation, path and principal component analysis were performed. The field experiment was conducted using serpentine alpha lattice design at the agronomy farm of the Institute of Agriculture and Animal Science (IAAS), Paklihawa campus, Nepal that comprised of twenty elite wheat genotypes. The grain yield of wheat was found to have significant negative association with days to heading (DTH) and days to booting (DTB) under all tested conditions. Plant height (Ph) was found to have a significant negative association with grain yield of wheat under irrigated conditions while significant positive association was observed across heat stress and heat drought conditions (p≤0.05). DTB, DTH, and Ph had a direct influence on the yield across all tested conditions. For the breeding program, dwarf genotypes that are earlier in booting and heading should be promoted under irrigated conditions whereas the taller genotypes that are earlier in booting and heading should be promoted under heat stress and heat drought conditions. Based on selected traits, BL 4919 and NL 1350 were selected as high yielding genotypes under irrigated condition, NL 1369 and NL 1417 under heat stress condition and NL 1350 and Bhrikuti under the heat drought condition. These genotypes should be promoted in the varietal improvement program of Nepal to release as a potential climate resilient variety.

AMMI GGE biplot analysis of wheat genotypes under heat stress and heat drought environment

Wheat is the third most important cereal crop of Nepal. Climatic changes have been a major threat on overall production and productivity of wheat in Nepal. With the aim of evaluating twenty elite wheat genotypes under heat stress and heat drought environments, a field experiment was conducted using alpha lattice design at Bhairahawa, Rupandehi, Nepal. The analysis of variance (ANOVA) revealed significant differences in the yield across wheat growing environments (p<0.001). Environment explained 75.11% of the total variation in grain yield. NL 1404 was the most stable followed by NL 1368, and NL 1413. NL 1376, NL 1369. NL 1386 was the best adapted genotypes under heat stress environments whereas NL 1384, Gautam, and BL 4949 were best adapted to heat drought environments. NL 1346 was the best genotype. WWW model explained NL 1346 won under heat drought environment and NL 1384 under heat stress environment. Mean vs. stability model showed NL 1346 was the above yielder and stable genotype. In ranking, NL1179 was concluded to be the ideal genotype. From the study, NL 1368 was found to be the winning genotype under heat drought and heat stress environments. These genotypes should further be evaluated to release as a variety.

Single- and multi-trait genomic prediction and genome-wide association analysis of grain yield and micronutrient-related traits in ICARDA wheat under drought environment.

Globally, over 2 billion people suffer from malnutrition due to inadequate intake of micronutrients. Genomic-assisted breeding is identified as a valuable method to facilitate developing new improved plant varieties targeting grain yield and micronutrient-related traits. In this study, a genome-wide association study (GWAS) and single- and multi-trait-based genomic prediction (GP) analysis was conducted using a set of 252 elite wheat genotypes from the International Center for Agricultural Research in Dry Areas (ICARDA). The objective was to identify linked SNP markers, putative candidate genes and to evaluate the genomic estimated breeding values (GEBVs) of grain yield and micronutrient-related traits.. For this purpose, a field trial was conducted at a drought-prone station, Merchouch, Morocco for 2 consecutive years (2018 and 2019) followed by GWAS and genomic prediction analysis with 10,173 quality SNP markers. The studied genotypes exhibited a significant genotypic variation in grain yield and micronutrient-related traits. The GWAS analysis identified highly significantly associated markers and linked putative genes on chromosomes 1B and 2B for zinc (Zn) and iron (Fe) contents, respectively. The genomic predictive ability of selenium (Se) and Fe traits with the multi-trait-based GP GBLUP model was 0.161 and 0.259 improving by 6.62 and 4.44%, respectively, compared to the corresponding single-trait-based models. The identified significantly linked SNP markers, associated putative genes, and developed GP models could potentially facilitate breeding programs targeting to improve the overall genetic gain of wheat breeding for grain yield and biofortification of micronutrients via marker-assisted (MAS) and genomic selection (GS) methods.

Evaluation of elite wheat genotypes in stress adoptive traits yield nursery under the agro climatic condition of Kohat Khyber Pakhtunkhwa-Pakistan

Evaluation of elite wheat genotypes in stress adoptive traits yield nursery under the agro climatic condition of Kohat Khyber Pakhtunkhwa-Pakistan

Genetic analysis of grain yield and its contributing traits in four bread wheat (Triticum aestivum L.) crosses using six parameter model

In order to create a successful and efficient breeding programme, it is highly helpful to analyse the gene action governing the expression of different traits. The objective of the present study was to use generation mean analysis to ascertain the kind and extent of gene action in bread wheat utilizing six generations (P1, P2, F1, F2, BC1 and BC2) of the four crosses, cross I (HD 2967 x PBW 752), cross II (RSP 561 x PBW 779), cross III (RSP 561 x PBW 780), and cross IV (JAUW 584 x WH 1184). These crosses included elite stripe rust resistant wheat genotypes in addition to locally adapted cultivars. The results showed that all the traits in all crosses had highly significant estimated mean effects (m), showing the quantitative inheritance of the selected traits. For grain yield and most of the selected characters, it was found that additive gene effects was shown to be less significance than dominance type gene effects. Among the different characters studied in the four crosses, the degree of dominance x dominance was large and negatively significant, whereas additive x additive gene actions were high and positively significance. In wheat breeding, it was found that selection for the improvement of grain yield and its contributing traits must be postponed until later generations because additive x dominant gene effects was of lesser significance. Keywords:  wheat; grain yield; additive; dominance; epistatic gene effects

Grain yield, chlorophyll and protein contents of elite wheat genotypes under drought stress

BackgroundDrought stress at different growth stages significantly alters growth, yield, and quality traits of wheat. However, great variability exists among genotypes regarding their response to drought stress. Therefore, determining the impacts of drought stress on yield and quality traits would help to select the superior genotypes. MethodsThis study investigated the effects of drought stress on wheat grain yield, chlorophyll, and protein contents. Fourteen (14) recently developed elite bread wheat (Triticum aestivum L.) genotypes were used in this study for evaluation under irrigated (full irrigation) and drought conditions (half of normal irrigation). The data relating to growth, yield and protein contents were recorded. ResultsSignificant differences (P ≤ 0.01) were noted among genotypes for all recorded traits. Drought stress significantly reduced the days to 50 % heading, days to 50 % maturity, grain filling, plant height (cm), number of spikes per m2, chlorophyll index (SPAD), peduncle length (cm), number of grains spike-1, thousand grain weight (g) and grain yield (kg ha−1). However, protein contents were increased under drought stress. Correlation analysis showed significant positive association of grain yield with thousand grain weight, number of spikes per m2, spike length, chlorophyll index, grain filling period and number of grains spike-1 under both irrigated and drought stress conditions. The protein contents expressed positive and negative relationship with yield under drought stress and irrigated conditions, respectively. Bioplot analysis revealed that genotype ‘V-19618′ and ‘V-19600′ proved superior under drought conditions regarding grain yield and related traits, while genotype ‘V-19574′ proved better under both irrigated and drought conditions. ConclusionsThese identified genotypes, i.e., ‘V-19618′ and ‘V-19600′ can be utilized in future wheat breeding programs to induce desirable characters for producing drought tolerant wheat genotypes.

Wheat spike blast: genetic interventions for effective management.

The fundamental concepts of the genetics, race classification and epidemiology of the Wheat spike blast causing fungus Magnaporthe oryzae pathotype Triticum (MoT) are still evolving despite of its discovery in 1985 in Brazil for the first time. The fungus seems to defy the research progress that is being made globally by continuously evolving into pathotypes which have already overcome the much celebrated 2NS resistance in wheat lines as well as few of the initially effective fungicides. The compartmentalized i.e. two speed genome of the MoT, conferring the fungus an evolutionary advantage, has emerged as a challenge for the wheat spike blast researchers complicating its already difficult management. The airborne fungus with a range of alternative hosts is finding new geographical niches situated on different continents and is a matter of great apprehension among the nations whose food security is primarily dependent on wheat. The wheat blast outbreak in Bangladesh during 2016 was attributed to an isolate from Latin America escaping through a seed import consignment while the latest Zambian outbreak is still to be studied in detail regarding its origin and entry. The challenges in dealing wheat spike blast are not only on the level of genetics and epidemiology alone but also on the levels of policy making regarding international seed movement and research collaborations. The present review deals with these issues mainly concerning the effective management and controlling the international spread of this deadly disease of wheat, with a particular reference to India. We describe the origin, taxonomy, epidemiology and symptomology of MoT and briefly highlight its impact and management practices from different countries. We also discuss the advances in genomics and genome editing technologies that can be used to develop elite wheat genotypes resistant against different stains of wheat spike blast.

Hybrid Seed Set in Relation with Male Floral Traits, Estimation of Heterosis and Combining Abilities for Yield and Its Components in Wheat (Triticum aestivum L.).

Breeding hybrids with maximum heterosis requires efficient cross-pollination and an improved male sterility system. Renewed efforts have been made to dissect the phenotypic variation and genetic basis of hybrid floral traits, although the potential of tailoring the appropriate flower design on seed setting is less known. To this end, elite wheat genotypes were crossed using a chemical hybridizing agent at different doses. A total of 23 hybrids were developed from a partial diallel design; and planted in an alpha lattice design with their parents at two locations in Morocco, for two years, to evaluate for yield components, heterosis and combining abilities. The 13.5 L ha−1 dose induced a maximum level of sterility (95%) and seed set showed large phenotypic variation and high heritability. In parallel, seed set showed tight correlation with pollen mass (0.97), visual anther extrusion (0.94) and pollen shedding (0.91) (p < 0.001), allowing direct selection of the associated traits. Using the combined data, mid-parent heterosis ranges were −7.64–14.55% for biomass (BM), −8.34–12.51% for thousand kernel weight (TKW) and −5.29–26.65% for grain yield (YLD); while best-parent heterosis showed ranges of −11.18–7.20%, −11.35–11.26% and −8.27–24.04% for BM, TKW and YLD, respectively. The magnitude of general combining ability (GCA) variance was greater than the specific combining ability (SCA) variance suggesting a greater additive gene action for BM, TKW and YLD. The favorable GCA estimates showed a simple method to predict additive effects contributing to high heterosis and thus could be an effective approach for the selection of promising parents in early generations.

GLM-PCA, a method to detect informative environments and phenotypic stable resistant sources of wheat to yellow rust in multi-environmental trials

Yellow rust (YR), caused by Puccinia striiformis f. sp. tritici, is one of the most important diseases of the wheat crop in all growing areas of the world. Screening of wheat genotypes for resistance in the frame of multi-environmental trials (METs) is a vitally important experiment in the wheat breeding program. The biggest challenge in the analysis of data obtained via scoring plant reaction to the disease is that they often do not satisfy the prerequisites of normality and homogeneity in the conventional parametric analysis. Even in the cases where non-parametric methods fail to distinguish genotype × environment (G × E) interaction, a generalization of PCA to exponential family likelihoods (GLM-PCA) can detect informative locations and phenotypically stable resistant genotypes. In this study, 35 elite wheat genotypes were screened for yellow rust resistance during two successive cropping seasons (2015–2016 and 2016–2017) at three hot spot locations in Iran. Based on the plots developed following GLM-PCA, two highly informative environments were identified exerting relatively huge disease pressure on the wheat genotypes. Moreover, genotypes URBYT(95–98)#4, URBYT(95–98)#7, and URBYT(95–98)#14 were visually detected as general resistant genotypes. The statistical method applied in this research to study G × E interaction could be proposed as a relevant approach to deal with categorical data obtained from a qualitative response in YR–wheat pathosystem under MET conditions.

English

Genetic diversity is the material basis for crop improvement. The genetic diversity of 17 wheat genotypes was evaluated using 25 agro-morphological characters and 10 simple sequence repeat (SSR) markers. The objective of this study was to determine the genetic diversity of elite stem rust resistant mutant lines in comparison with their adaptable but susceptible parent varieties using morphological traits and molecular markers. The results obtained showed significant variation in morphological traits and molecular makers existed. Morphological diversity between mutant lines and their parent varieties was mainly separated by grain yield per spike, 1000 grain weight and maturity time period. The dendrogram based on 10 SSR markers grouped the 17 genotypes into three major clusters and six sub-clusters with mutants clustering with their respective parents. 10 SSR primer pairs yielded 13 polymorphic loci with a percentage of 92.86%. The mean number of alleles per locus in each group was 2.0 and the mean number of polymorphic alleles per locus was 1.9286. The gene diversity ranged from 0 to 0.4893 for each sample. Results showed it is possible to classify genetic diversity of elite wheat genotypes and select them for the highest genetic diversity. The results can be used in selecting diverse parents in breeding programs and also in maintaining genetic variation in the germplasm. Key words: Genetic diversity, molecular markers, morphological traits, wheat.

Studies on reproductive behavior of fifteen elite wheat genotypes in relation to hybrid development

Studies on reproductive behavior of fifteen elite wheat genotypes in relation to hybrid development

Assessment of terminal drought tolerance among elite wheat (Triticum aestivum L.) genotypes using selected agronomic and physiological traits

ABSTRACTThe selection response of wheat (Triticum aestivum L.) under water-limited condition can be enhanced through breeding novel genotypes possessing drought-adaptive and yield-related agronomic and physiological traits. The objective of this study was to evaluate terminal drought tolerance among bread wheat genotypes and select superior parents for breeding. Agronomic and physiological responses of 28 wheat lines were assessed under well-watered (WW) and terminal drought (TD) treatments using a 7 × 4 alpha-lattice design under rainout shelter (RS) and glasshouse (GH) environments. Significant (p ≤ 0.05) genotype × environment interaction effects were observed for number of days to heading (DTH), number of days to maturity (DTM), number of productive tillers per plant (TN), grain yield (GY), thousand kernel weight (TKW), stomatal conductance (SC), leaf canopy temperature (LCT) and chlorophyll content index (CCI) suggesting varied genotypic response under WW and TD treatments. Correlation analysis revealed significant associations TN and GY (r = 0.67; p ≤ 0.001), TKW and GY (r = 0.72; p ≤ 0.001), CCI and GY (r = 0.39; p ≤ 0.05) under TD treatment. Drought tolerant wheat genotypes such as LM100, LM72, LM22 and LM95 are useful for direct cultivation and for developing breeding populations with enhanced yield performance.

Genotype-by-environment interaction and selection of elite wheat genotypes under variable rainfall conditions in northern Ethiopia

ABSTRACTProductivity of bread wheat (Triticum aestivum L.) in Ethiopia can be improved by the identification of adaptable, high-yielding and rust-resistant genotypes through the evaluation of elite wheat genotypes for yield in multi-environment trials. Thus, our objective was to evaluate 16 bread wheat genotypes across four locations in 3 years (2015, 2016, and 2017) during the main crop production seasons in Ethiopia. Grain yield data were subjected to the additive main effects and multiplicative interaction (AMMI), genotype plus genotype by environment interaction (GGE) biplot and AMMI stability value (ASV) analyses to exploit genotype-by-environment interaction (GEI). Further, the correlation between total rainfall received during the growing seasons and grain yield performance was computed. Variation attributable to genotypes, environments, and GEI was highly significant (P < 0.01). Genotypes ETBW 8160 and ETBW 8180, with grain yield of 2529 and 2512 kg ha−1, respectively, were identified by AMMI, GGE, and ASV analyses as high-yielding with stable performance. These genotypes are recommended for further breeding or production in the region. GGE biplot analysis showed that years within locations were grouped into different clusters without forming mega-environments. Mean grain yield of test genotypes was significantly correlated (r = 0.64; p ≤ 0.01) with rainfall received during September, indicating that the increase in rainfall in this month would have a positive effect on grain yield. However, the rainfall amount during September has decreased and is erratic. This indicates the need for supplemental irrigation for the wheat farms.

Production of wheat-doubled haploids resistant to eyespot supported by marker-assisted selection

Wheat is one of the most important crops cultivated all over the world. New high-yielding cultivars that are more resistant to fungal diseases have been permanently developed. The present study aimed at the possibility of accelerating the process of breeding new cultivars, resistant to eyespot, by using doubled haploids (DH) system supported by marker-assisted selection. Two highly resistant breeding lines (KBP 0916 and KBH 4942/05) carrying Pch1 gene were crossed with the elite wheat genotypes. Hybrid plants of early generations were analyzed using endopeptidase EpD1 and two SSR markers linked to the Pch1 locus. Selected homozygous and heterozygous genotypes for the Pch1-linked EpD1b allele were used to produce haploid plants. Molecular analyses were performed on haploids to identify plants possessing Pch1 gene. Chromosome doubling was performed only on haploid plants with Pch1 gene. Finally, 65 DH lines carrying eyespot resistance gene Pch1 and 30 lines without this gene were chosen for the eyespot resistance phenotyping in a field experiment. Results of the experiment confirmed higher resistance to eyespot of the genotypes with Pch1 in comparison to those without this gene. This indicates the efficiency of selection at the haploid level. How to cite: Wiśniewska H, Majka M, Kwiatek M, et al. Production of wheat doubled haploids resistant to eyespot supported by marker-assisted selection. Electron J Biotechnol 2019;37. https://doi.org/10.1016/j.ejbt.2018.10.003

Canopy and Ear Traits Associated With Avoidance of Fusarium Head Blight in Wheat.

Doubled haploid and elite wheat genotypes were ground inoculated in three field experiments and head spray inoculated in two glasshouse experiments, using mixed Fusarium and Microdochium species, to identify crop canopy and ear traits associated with Fusarium head blight (FHB) disease. In all experiments, flag leaf length and tiller number were consistently identified as the most significant canopy traits contributing to progression of FHB caused by Fusarium graminearum, F. culmorum, and F. avenaceum. The influence of ear traits was greater for F. poae that may possess more diverse routes for transmission and spread. Consistently, spikelet density was associated with increased disease severity in the field. F. graminearum, F. culmorum, and F. langsethiae were the main mycotoxin producers and their respective toxins were significantly related to fungal biomass and number of spikelets per ear. Genotypes with lower tiller numbers, shorter flag leaves and less dense ears may be able to avoid FHB disease caused by F. graminearum, F. culmorum, F. avenaceum, or Microdochium species however selection for these canopy and ear architectural traits to enable disease avoidance in wheat is likely to result in a potential trade-off with grain yield and therefore only moderately advantageous in susceptible genotypes.

EVALUATION OF AGRONOMIC TRAITS FOR YIELD AND YIELD COMPONENTS IN WHEAT GENOTYPES WITH RESPECT TO PLANTING DATES

Fourteen genotypes including two checks varieties were evaluated for agronomic traits and their adaptability study on two different sowing dates at the experimental farm of Nuclear Institute for Food and Agriculture, Tarnab, Peshawar, Pakistan. The combined analysis of variance showed that there were significant variations among genotypes, dates of sowing and their interaction. Based on regression coefficient (bi ) and mean square deviation from linear regression for the individual genotypes regarding the parameters Viz. plant height, spike length, spikelets spike-1, number of tillers plant-1 and grain yield (kg) plot-1 under consideration, most of the genotypes responded negatively with respect to all the traits under late planting condition. However, some of the genotypes such as CT-09117, CT-09137, CT-09141 and SRN-09111 revealed stable performance with respect to the yield assorted traits. They have been recommended for the late planting conditions where sowing is delayed due to some unavoidable circumstances than the other elite wheat genotypes

Canopy temperature depression at grain filling correlates to winter wheat yield in the U.S. Southern High Plains

Wheat breeding has improved drought tolerance over the years. However, our knowledge on drought tolerance in relation to the diurnal pattern of canopy temperature (CT) and grain yield is limited. A three-season wheat field study ending 2012, 2015, and 2016 was conducted at Bushland, Texas to investigate the relationship between canopy temperature depression (CTD) and yield during the grain filling period. For each season, 20 elite wheat genotypes were grown under dryland conditions, and CT was measured by Smart Crop wireless IRT sensors every 15min continuously for 12–15days during mid-grain filling (∼10–25days after flowering). There was a genotypic variation for CTD regardless of time of the day; however, the variation was more evident during the day time (10:00–18:00h), with the smallest CTD (i.e., warmer canopy) at 14:00–15:00h. In a dry season of 2012, TAM 304, TAM 112, Dumas, and Hatcher had greater CTD (i.e., cooler canopy) than other genotypes. In two wet/near normal seasons (2015 and 2016) Duster, TAM 111, TAM 110, TAM 112, and TAM 105 had greater CTD. There was a significant (P<0.05) positive linear relationship between grain yield and day-time CTD. Hence, a cooler plant canopy during the mid-grain filling in winter wheat appears to be an important indicator of greater drought tolerance and yield under dryland condition. This knowledge may help breeders to conduct high-throughput field phenotyping in large breeding populations.