Thousand-kernel Weight Research Articles

INFLUENCE OF TARGET SEEDING RATES BASED ON THOUSAND KERNEL WEIGHT ON VEGETATIVE GROWTH TRAITS OF TRITICALE, VARIETY ADMIRAL- Part I.

A field experiment was conducted during two seasons 2019-2020 and 2020-2021 at the Grdarasha Research Station of the Agricultural Engineering Sciences College-Salahaddin University-Erbil. The experiment was designed as factorial within randomized complete block design (RCBD), with three replicates. The first factor included three target seeding rates of Triticale (×Triticosecale wittmack, variety Admiral (200,250,and300seeds.m-2), while the second factor was three grain size grades whole, thousand kernels weight (TKW) 47.32 g, heavy seeds, TKW 54.04 and light seeds TKW 40.18 g. The results revealed to no significant influence of seeds weight or seeding rates and their interaction on this trait excluding whole sample seed (ungraded) at the rate target of 300 seeds.m-2, which was significantly reduced flag leaf area. Leaf area index was significantly varied among seed weight and target seeding rates or by their interactions. The plant height of triticale although it was higher for heavy seeds and higher target seeding rates, but it was not reached significant level, either by seed grade or target seed rate and their interactions in both. Plant height ranges from 88.00 for heavy seeds at rate 300 seeds.m-2 to 83.00 for light seeds at rate 200 seeds.m-2 for the season 2019-2020. The highest tillers number was recorded for seed rate 300.m-2 with whole ungraded seeds (176.00).

Early Flowering and Maturity Promote the Successful Adaptation and High Yield of Quinoa (Chenopodium quinoa Willd.) in Temperate Regions

Quinoa (Chenopodium quinoa Willd.) can offer an alternative for staple food considering its tolerance to abiotic stresses and high seed quality. However, its cultivation in temperate regions has not been successful due to its photoperiod sensitivity and low seed yield. This study investigated the agronomical performance and quality traits of 48 accessions for cultivation in northern Europe. We conducted two-year field trials and phenotyped traits related to phenological development, plant architecture, yield components, seed quality, and disease resistance. The major determinants of seed yield in this study were days to flowering, days to maturity, thousand-kernel weight, and panicle density, while downy mildew susceptibility and stem lodging showed a negative correlation with seed yield. We developed a selection index to enable simultaneous selection based on different important agronomical traits. We evaluated the stability of different accessions over the two years of the experiment. Finally, we provided a list of 10 selected accessions that can be directly integrated and serve as new crossing parents in quinoa breeding programs for temperate regions.

Unveiling Phenotypic and Environmental Dynamics: Exploring Genetic Stability and Adaptability of Faba Bean Cultivars in Norwegian Climates

ABSTRACTThis study evaluated 22 spring‐type faba bean cultivars in the main areas for cultivation of faba bean in Norway to assess the variation of 14 faba bean traits due to cultivar (G), environment (E), and their interaction (G × E), and to assess their stability across environments by using the additive main effects and multiplicative interaction (AMMI) analysis and coefficient of variation (CV). Significant G, E, and G × E effects were found for most traits, with environment accounting for much of the variance in yield and the growing degree days (GDD) to different developmental stages. Yield was highly correlated with thousand kernel weight (TKW) and GDD to BBCH 89 (maturation). The stability of the cultivars was studied for yield, TKW, and GDD to BBCH 89. Stability analysis using the AMMI stability value, yield stability index, CV, and the average sum of ranks identified Birgit, Stella, Bobas, and Macho as the most stable high‐yielding cultivars across environments, achieving a mean yield of 6–6.4 tons ha−1. Bobas, Macho, Stella, and Yukon had the most stable TKW (612–699 g) and Bobas, Capri, Trumpet, and Vertigo were the most stable regarding GDD to BBCH 89 (1257°C days, with a base temperature of 5°C). These stable cultivars can be utilized in breeding programs to achieve high and stable faba bean yield in the main growing areas of Norway and other Nordic‐Baltic countries.

Phenotypic Selection of Bread Wheat (Triticum aestivum L.) Elite Lines for Diseases Resistance and Yield Potential

Wheat diseases and pests globally threaten wheat production. Wheat rust diseases are the most distractive biotic constraint of wheat in Ethiopia. Therefore, this experiment aimed to select and develop wheat rust resistance bread wheat varieties for the farmers. The result of the study revealed highly significant variation existed among tested genotypes for Plant Height (PHT), Days to Heading (DTH), Days to Maturity (DTM), Thousand Kernel Weight (TKW), Hectoliter Weight (HLW), and Yield (YLD) at (P< 0.001). Out the forty-nine introduced genotypes, five genotypes: EBW222153, EBW222159, EBW222160, EBW222162, and EBW222164, showed resistance to moderately resistance for both yellow rust and stem rust diseases across the two test locations. Also, they delivered high average yield: 5.9 tha-1, 4.46 tha-1, 5.17tha-1,4.15 tha-1, and 4.79tha-1 respectively. Furthermore, all the above-mentioned genotypes, except EBW222162, showed significantly higher yield at (P<0.05) than the check variety, Shaki. Furthermore, EBW222153, EBW222159, EBW222160, EBW222162, EBW222164, and EBW222178 would resistance to moderately resistance for stem rust at Melkasa. Thus, the selection of these genotypes and advancing to the next stage of breeding pipelines enables to release noble bread wheat varieties for the farmers.

Influence of Wheat Cultivars, Infection Level, and Climate after Anthesis on Efficacy of Fungicide for Control of Fusarium Head Blight in the Huang-Huai-Hai Plain of China

Fusarium head blight (FHB), caused by the Fusarium graminearum species complex, causes significant losses in grain yield and quality of wheat (Triticum aestivum) by inducing floret sterility. Grains become contaminated with mycotoxins, especially deoxynivalenol (DON), making them unsuitable for consumption. To clarify the impact of wheat cultivar resistance, infection level, and climate after anthesis on the efficacy of a fungicide for the control of FHB, we treated two moderately susceptible cultivars and 11 susceptible cultivars with fungicide (48% phenamacril + tebuconazole) at anthesis over two years. FHB incidence (INC), disease severity index (DSI), Fusarium-damaged kernels, DON contamination, thousand-kernel weight, and yield were evaluated under artificially inoculated and naturally infected field trials in 2018 and 2021. The results of multi-factor variance analysis show that the control efficacy with respect to INC and DSI is affected by cultivar, fungicide, infection level, and climatic conditions including the average daily temperature, average daily relative humidity, and total rainfall from anthesis to 21 days after anthesis (p < 0.01). Notably, cultivar resistance (deviance = 13.34, 9.55, and 11.22) is more important than fungicide (deviance = 5.77, 6.66, and 6.69) to control the efficacy of INC, DSI, and DON. The results also suggest that infection level appears to be more important than cultivars and fungicide to control the efficacy of INC, and more important than fungicide to control the efficacy of DSI. Total rainfall is more important than other climatic factors. Our results reveal that fungicide is more effective in moderately susceptible cultivars (‘Zhengmai 9023’ and ‘Xinong 979’, 89.5%~98.9%) and some susceptible cultivars than in other susceptible cultivars (‘Zhengmai 7698’ and ‘Zhoumai 27’, 51.9%~67.2%). Thus, integrating cultivar resistance with fungicide application can be an effective strategy for the management of FHB and DON in winter wheat in the Huang-huai-hai Plain of China.

The Influence of Sowing Date on the Primary Yield Components of Maize

The sowing date of maize significantly impacts its main yield elements. The experiment, conducted at the Research and Development Station for Cattle Breeding (R.D.S.C.B.) Târgu Mureș, Sângeorgiu de Mureș, România, from 2018 to 2021, involved nine maize hybrids from different maturity groups, sown on three dates: early sowing (ES) at 6 °C soil temperature, optimal sowing (OS) at 10 °C soil temperature, and late sowing (LS) two weeks after the optimal date. The experiment was placed in a poly-factorial experience of type: A × B × C × C − R: 3 × 9 × 4 − 3, organized according to the subdivided plots method. The study examined the influence of sowing date on grain yield (GY), thousand-kernel weight (TKW), test weight (TW), percentage of grains per cob (% G/C), and grain humidity at harvest (GHH). The results indicated that yield was not negatively impacted by early or late sowing compared to the optimal date, with differences of 52 kg ha−1 between ES and OS, 147 kg ha−1 between ES and LS, and 95 kg ha−1 between OS and LS. ES increased TW (723.4 kg hl−1) and % G/C (86.7%), but reduced GY (13,377 kg ha−1), TKW (335.3 g), and GHH (19.5%). Conversely, LS positively influenced GY (13,524 kg ha−1), TKW (356.7 g), and GHH (23.9%), but negatively affected TW (692.8 kg hl−1) and % G/C (84.9%). Yield data obtained by P9900 and Kapitolis hybrids suggest that they are suitable for early sowing.

Phenotypic diversity of key adaptive traits in advanced Nordic and Baltic spring wheat (Triticum aestivum L.) breeding material

Wheat (Triticum aestivum L.) has become the most widely grown cereal crop in the Nordic-Baltic region, but due to climate change, its yields are under increasing risk. Here we present results of an international effort to use available wheat germplasm from the region to identify tools and genotypes for breeding wheat varieties with improved stability. We formed a panel of 300 spring wheat genotypes from the Nordic-Baltic region and studied their phenotypic diversity across environments to identify genotypes with high potential for adaptation to a changing climate. Field experiments were carried out in 2021 and 2022 in Estonia, Latvia, Lithuania and Norway. The performance and stability of yield (GY), protein content (PC), thousand kernel weight (TKW), test weight (TW), length of growing period (GP), and nine other traits were studied. Drought and excessive rainfall occurred in the Baltic countries in 2021–2022, whereas the weather in Norway was more stable. High variability for most traits, and significant GxE effects for all studied traits, were identified. We identified stable genotypes combining yield and quality using the AMMI model-based Weighted Average of Absolute Scores index (WAASB). Finally, we selected nineteen superior genotypes that combined high yield with high values of important quality traits. Thus, combining broad Nordic-Baltic wheat germplasm with extensive field phenotyping, we identified promising breeding material to develop climate-ready spring wheat varieties for the region.

Assessing Heat Stress Tolerance of Wheat Genotypes through Integrated Molecular and Physio-Biochemical Analyses

Heat as an abiotic stress significantly impairs the sustainable productivity of wheat (Triticum aestivum L.). To determine the tolerance of genotypes to heat stress, a comprehensive approach should be used that integrates simultaneous phenotyping and genotyping analyses. The aim of this study is to identify local heat-tolerant genotypes using simple sequence repeat (SSR) markers and evaluate the selected genotypes under field conditions for their tolerance to heat stress. Of the 12 SSR markers that showed polymorphism, eight were associated with six important traits. The use of hierarchical cluster analysis (HC) based on SSR markers led to the identification of 13 genotypes that showed varying results and were grouped into three distinct heat tolerance classes: tolerant (T), moderately tolerant (MT), and sensitive (S). The results showed that heat stress had a significant effect on 19 traits under this study, with significant variation in tolerance to heat stress between genotypes. The tolerant genotypes exhibited a range of average thousand-kernel weight (TKW) values between 40.56 and 44.85, while the sensitive genotype (Yecora Rojo) had an average TKW of 35.45. Furthermore, the tolerant genotypes showed two to three times higher levels of antioxidants compared to the sensitive genotypes when exposed to heat stress. Among the traits analyzed, six showed a favorable combination of high heritability (>60%) and genetic gain (>20%). Through the integration of principal component analysis and stepwise multiple linear regression, it was determined that six traits (grain yield, 1000-kernel weight, plant height, intercellular carbon dioxide, flag leaf area, and grain filling duration) revealed differences between the 13 genotypes. HC analysis of the six traits resulted in the same division of genotypes into three main categories as observed in an HC analysis based on SSR markers. It is worth noting that Saudi wheat, including KSU106, KSU105, and KSU115 as local genotypes, in addition to the 16HTWYT-22 genotype, showed higher heat tolerance compared to the other genotypes tested, indicating its potential suitability for agriculture in Saudi Arabia. These results contribute to breeding programs focused on developing heat-tolerant wheat varieties and accelerate progress in wheat productivity improvement programs.

DETERMINING THE ASSOCIATIONS BETWEEN CROP PHENOLOGY, GROWTH, YIELD, AND YIELD-RELATED PARAMETERS OF MALT BARLEY (HORDEUM VULGARE)

The study was conducted at two locations, namely Holeta and Kulumsa Agricultural research centers of Ethiopia, for 2 consecutive years from 2019 to 2021 main cropping seasons. The objective of the experiment was to determine the association between crop phenology, growth, yield, and yield-related parameters. One variety of newly harvested pre-basic seed class of malt barley variety, namely IBON 174/03, was used for the experiment. Total number of treatment combinations was eighteen. The treatments were laid out in a randomized complete block design in two factorial arrangements with three replications. The factors are five deterioration/aging days 0 (control/un-aged), 2, 4, 6, 8, and 10 days and three seeding rates (75, 100, and 125 kg/ha). Before artificial deterioration, the seed moisture content for all treatments was 12.5%. Seeds were subjected to artificial deterioration treatments and placed in an incubator at 42°C for 0 (control), 2, 4, 6, 8, and 10 days at approximately 100% relative humidity. The result revealed that above-ground dry biomass (AGDBM) and grain yield (GYLD) per hectare were significantly affected both by deterioration days and seed rate. As deterioration day increased the mean value for AGDBM and GYLD per hectare was significantly reduced and as the seeding rate increased from 75 to 125 kg/ha AGDBM and GYLD per hectare increased by 30.53% and 21.01%, respectively. The main effect of deterioration days showed a significant difference (p<0.05) for spike length (SL) as deterioration days increased from 2 to 10 days SL was reduced by 7.7–22.62% as compared to un-aged treatment but, the percentage reduction for barley seed deteriorated for 6 and 10 days recorded similar value which is 22.62% as compared to un-aged treatment. Seed per spike and thousand kernels weight were influenced by the main effect of seed rate but, not by deterioration days. As the seeding rate increased from 75 to 125 kg/ha, number of seeds per spike reduced by 4.75% whereas, seeds sown at a low seeding rate (75 kg/ha) recorded a higher thousand kernel weight (TKW) as compared to the seed sown at higher seed rate 100 and 125 kg/ha. Interaction effect of deterioration days and seed rate were only significant for TKW and it was non-significant for the rest of the evaluated crop phenology, growth, yield, and yield-related parameters. This study was only a field experiment result based on further conclusions on how aging can affect the genetic potential such as germination and viability; laboratory inclusive test will be required.

A rare natural variation in TaFT-D2 underlies QTss.cas-3D associated with increased total spikelet number per spike in wheat

Total spikelet number per spike (TSS) is a crucial yield component in wheat. Dissecting and characterizing major stable quantitative trait loci (QTL) associated with TSS can significantly enhance the genetic improvement of yield potential. In a previous study, we identified a stable major QTL for TSS, named QTss.cas-3D. In the present study, we conducted fine mapping of QTss.cas-3D, interval to approximately 6.35 Mb, ranging from 105.03 to 111.38 Mb, based on the IWGSC RefSeq v2.1. Through genome re-sequencing and gene function annotation, we identified TraesCS3D03G0308000 (TaFT-D2) as the candidate gene. Phenotypic evaluation with paired near-isogenic lines revealed that this locus predominantly increases kernel number per spike by enhancing TSS and fertile spikelet number per spike, without significantly affecting thousand-kernel weight or tiller number. The presence of the TaFT-D2 allele in the parent P3228, which is rare in nature populations, highlights its potential value. This study provides a valuable gene resource and functional marker for wheat molecular breeding aimed at improving TSS and establishes a foundation for gene functional analysis of TaFT-D2.

The Impact of Salinity on the Productivity and Quality of Durum and bread Wheat

Salinity poses a significant challenge to the quality and productivity of crops. In the primary wheat cultivation areas worldwide, salinity negatively affects wheat growth, yield, and quality. To address this issue, the development of tolerant wheat varieties through selective breeding techniques is essential. The aim of this study was to assess the effects of salinity on grain yield, protein content, and thousand-kernel weight (TKW) among 55 different varieties and accessions of bread and durum wheat. The findings revealed that the application of salt treatment (100 mM NaCl solution) resulted in reduced growth and yield production in 45 bread and durum wheat varieties. However, 6 durum wheat varieties, 3 durum wheat accessions, and 1 common wheat accession showed insignificant susceptibility to salinity. These included Chryssodur from Greece, Saragolla, Silur, and Dakter from Italy, Sculptur from France, Karim from Tunisia, Algeria 70-2 from Algeria, Ethiopia 201 and Ethiopia 229 from Ethiopia, and the Morocco 85 accession of bread wheat from Morocco. The decline in grain yield could be attributed to salinity, which led to a decrease in photosynthetic capacity, resulting in reduced starch synthesis and accumulation in the grain. Furthermore, the study demonstrated that winter wheat exhibited greater tolerance to salt stress compared to spring wheat, and durum wheat displayed higher tolerance than common wheat. Additionally, salt accumulation was found to increase protein content in five varieties and one accession of durum wheat. This variation may be linked to the relatively stable nitrogen metabolism under salt stress, contributing to higher protein concentrations. TKW also decreased in all 10 varieties and accessions, irrespective of the species.

Genome-wide association and genomic prediction study of elite spring bread wheat (Triticum aestivum L.) genotypes under drought conditions across different locations

Abiotic stress, notably drought, impacts wheat production globally, but more so in central and South Asia, North Africa (CWANA), and sub-Saharan Africa (SSA). The current study attempts to identify significant markers linked to drought and heat tolerance and assess genomic prediction. A genome-wide association study was conducted using the 10 K wheat SNP markers for grain yield and related traits of 246 spring bread wheat genotypes from ICARDA. Traits including grain yield (GY), days to heading (DHE), days to maturity (DMA), plant height (PLH), and thousand kernel weight (TKW), were evaluated across six different locations, spanning two years 2015–2016 and 2016–2017, as per variance analysis. Grain yield and related-traits showed a considerable variation among genotypes. Moreover, GWAS using a mixed linear model (MLM), revealed 65 marker-trait associations (MTAs) across the six environments on 16 chromosomes. With an average r2 value of 0.26, Genome D has the highest linkage, followed by Genomes B and A with r2 values of 0.22 and 0.21, respectively. GY had the highest MTA rating (35), followed by TKW (9) and 3 for each of the other agronomic traits (DHE, DMA, PLH) at Merchouch station. The marker “CAP8_c1393_327” was the most significant associated marker correlated with grain yield located on chromosome 3 A across Sid El Aidi station. Additionally, the SNP markers “wsnp_Ra_c26091_35652620” displayed extremely significant and stable MTA for TKW on chromosome 5B at Merchouch station. The markers and candidate genes reported throughout this study have the potential to be used in marker-assisted selection to enhance wheat genotypes in terms of yield and resistance to drought limitations.

The Infection of Barley at Different Growth Stages by Bipolaris sorokiniana and Its Effect on Plant Yield and Sowing Value

Bipolaris sorokiniana, a barley pathogen, can infect via seeds, co-growing plants, or soil, causing yield and seed value reductions. This study aimed to assess B. sorokiniana’s impact at various growth stages on seed yield and quality. Results showed no direct impact on yield (which ranged from 0.49 kg·m−2 for the naked variety Rastik to 0.77 kg·m−2 for the Widawa variety), but revealed significant seed quality differences. Thousand kernel weight (TKW) and germination capacity (GC) varied notably between examined varieties. The largest kernels were observed for the Bryl variety (27.33 g), which also had the best germination (82.8%). The variety Ryton had the smallest kernels (24.04 g), while the poorest germination (56.7%) was observed for naked kernels of Rastik. A seed health analysis found a relation between inoculation stage and the intensity of spontaneous infection by pathogenic fungi, ranging from 86.4% for the control to more than 95% for the kernels harvested from plants inoculated at the flowering stage. Strong correlation emerged between B. sorokiniana grain infection and germination capacity, highlighting the fungus’s role in seed quality decline.

Estimation of Phenotypic and Genotypic Correlation Analysis in F3 Populations of Bread Wheat Genotypes

Wheat is one of the most important crops all over the world in terms of yield, production, consumption, cultivation, and adoptability. Wheat genotypes exhibiting different yield associated traits which influence each other in many ways. Therefor genotypic and phenotypic correlations are the breeder’s utmost priority to know about the inter-relationship between two or more traits which may be either directly influencing each other in a positive direction or indirectly swaying each other in a negative direction in breeding programs. To find out phenotypic and genotypic correlations among different productive traits, this study was designed at the research area of The Department of Plant Breeding and Genetics, The University of Agriculture, Peshawar, during 2022-23. The experiment was carried out by using 27 wheat genotypes comprising of nine parents and 18 F3 populations evaluated in RCB design with three replications. Overall the study exhibited that kernel yield plant-1, which is one of the most yield contributing trait, was significantly correlated with thousand-kernel weights, tillers plant-1and biomass yield, along some other yield contributing traits. The parental genotype, Janbaz, and cross combinations Watan × AUP-5008, Pirsabak-2005 × AUP-5008, Saleem-2000 × Janbaz and Watan × Tatara were the most promising genotypes for most of quantitative traits and; hence are recommended to be evaluated in further breeding schemes. Both phenotypic and genotypic correlation study exhibited that kernel yield spike-1 was significant and positively associated with plant height, tillers plant-1, thousand-kernel weight and biomass yield. Based on correlations, yield, and production the parental genotype, Janbaz, and F3 combinations Watan × AUP-5008, Pirsabak-2005 × AUP-5008, Saleem-2000 × Janbaz and Watan × Tatara were the most promising genotypes for most of the quantitative traits, which can be incorporated in further breeding program.

Study of the effects of silicon and sulphur foliar fertilization on yield components and yield in different winter oat cultivars

The aim of this work was to study the effect of sulphur and silicon foliar fertilisation treatment in different Hungarian-bred winter oat cultivars on the yield and the yield components, e.g. panicle ear-1 numbers per square meters, number of panicle nodes, number of spikelets per panicle, and thousand kernel weight (TKW) in the 2022–2023 growing season. The obtained results show that the applied fertilisers influenced the measured parameters, and we get the highest yield at the combined treatment – where silicon and sulphur was both applied –, and unexpectedly the lowest when only silicon was applied during the growing period. We measured the highest number of panicles m-2 at the sulphur treated experimental plots, and the lowest at the silicon treatment. We measured the average number of nodes of the panicle, and we can say that the sulphur fertilisation caused significantly higher values than any other treatment. Talking about the spikelet numbers, we get the highest value at the sulphur fertilisation, and the lowest at the control plots. However, our result wasn’t that prominent in the case of TKW, we get the highest weight at the silicon treatment, and the lowest at the sulphur fertilisation.

Contrasting Performance of Two Winter Wheat Varieties Susceptible to Leaf Rust under Diverse Pathogen Pressure, Fungicide Application, and Cultivation Practices.

This study investigated the relationship between yield, thousand kernel weight (TKW), and crude protein of soft white winter wheat-club variety (Barbee) and soft white winter wheat common variety (Zvezdana) susceptible to leaf rust and powdery mildew under different cultivation practices. Results revealed divergence in associations between yield, TKW, and crude protein loss of winter wheat varieties susceptible to obligate pathogens. Under the same level of leaf rust infection, N-input limited yield loss of the two varieties but not to the same extent. TKW loss was affected only by variety×cultivation practice and was significantly correlated with yield loss (r = -0.727, p = 0.011) and crude protein loss (r = -0.600, p = 0.05) only in club winter wheat. We suspected that Ninput affects the difference in the relationship between yield and TKW loss among varieties. Crude protein and yield loss had a low association (R2 = 18%, p = 0.05). Finally, this study indicated that more attention should be paid to the determination of pathogen pressure that triggers yield loss. It also pointed out that yield, TKW, and crude protein response to fungicides could differ in susceptible varieties. The contribution of fungicide to yield enhancement was highly associated with the specific reaction of the variety to pathogen infection rather than solely the disease level itself.

Dissection of the Genetic Basis of Genotype by Environment Interactions for Morphological Traits and Protein Content in Winter Wheat Panel Grown in Morocco and Spain.

To fulfill the growing demand for wheat consumption, it is important to focus on enhancement breeding strategies targeting key parameters such as yield, thousand kernel weight (TKW), quality characteristics including morphological traits, and protein content. These elements are key to the ongoing and future objectives of wheat breeding programs. Prioritizing these factors will effectively help meet the rising demand for wheat, especially given the challenges posed by unpredictable weather patterns. This study evaluated the morphological traits and protein content of 249 winter wheat varieties and advanced lines grown in eleven different environments in Morocco and Spain incorporating three varied sowing dates. The results showed considerable variability in morphological traits and protein content. Significant correlations were observed among various grain traits, with most grain morphological parameters exhibiting negative correlations with protein content. Differences across environments (p ≤ 0.01) in all traits, genotypes, and genotype by environment interaction were significant. A factorial regression analysis revealed significant impacts of environmental conditions on all grain morphological parameters, protein content, and TKW during the three growth stages. The study identified several high-performing and stable genotypes across diverse environments, providing valuable insights for wheat breeding programs such as genotypes 129, 234, 241, and 243. Genome-Wide Association Studies pinpointed 603 significant markers across 11 environments, spread across chromosomes. Among these, 400 markers were linked with at least two traits or observed in at least two different environments. Moreover, twelve marker-trait associations were detected that surpassed the Bonferroni correction threshold. These findings highlight the importance of targeted breeding efforts to enhance wheat quality and adaptability to different environmental conditions.

Genome-Wide and Transcriptome-Wide Association Analysis Identifies qRS-6D and Its Candidate Genes Regulating Root Development of Wheat Seedlings

Wheat (Triticum aestivum L.) is one of the most important cereal crops worldwide, and its production is challenged by global climate change and a shortage of resources. The root system plays a vital role in uptaking water and nutrients and sensing soil environmental signals, and it has great potential to improve the final yield and stress tolerance of wheat. In order to further explore the genes regulating root development, this study focused on qRS-6D, located on chromosome 6D and spanning from 462,701,391 to 465,068,943, which was significantly associated with the total root length, root volume, root surface, and root fresh weight in our previous GWAS analysis. Firstly, its genetic effects were validated using an F6 segregating population by comparing the root-related traits of homologous lines harboring the alternative haplotypes of this QTL. Then, the number of causal genes of this QTL was narrowed down to four with a transcriptome-wide association study. Additionally, qRS-6D has been demonstrated to have genetic effects on several yield- (kernel length, kernel width, and thousand-kernel weight) and plant structure-related traits (plant height, peduncle length, total tiller number, productive tiller number, flag leaf length, and flag leaf angle). Relatively, the frequency of the favorable haplotype increased with the wheat breeding practice. This study provides a reliable genetic locus to improve root development and structure and evaluate its application potential in wheat breeding improvement.

Molecular mechanisms underlying low temperature inhibition of grain filling in maize (Zea mays L.): coordination of growth and cold responses.

Low temperature (LT) greatly restricts grain filling in maize (Zea mays L.), but the relevant molecular mechanisms are not fully understood. To better understand the effect of LT on grain development, 17 hybrids were subjected to LT stress in field trials over 3 years, and two hybrids of them with contrasting LT responses were exposed to 30/20°C and 20/10°C for 7 days during grain filling in a greenhouse. At LT, thousand-kernel weight declined, especially in LT-sensitive hybrid FM985, while grain-filling rate was on average about 48% higher in LT-tolerant hybrid DK159 than FM985. LT reduced starch synthesis in kernel mainly by suppression of transcript levels and enzyme activities for sucrose synthase and hexokinase. Brassinolide (BR) was abundant in DK159 kernel, and genes involved in BR and cytokinin signals were inducible by stress. LT downregulated the genes in light-harvesting complex and photosystem I/II subunits, accompanied by reduced photosynthetic rate and Fv/Fm in ear leaf. The LT-tolerant hybrid could maintain a high soluble sugar content and fast interconversion between sucrose and hexose in the stem internode and cob, improving assimilate allocation to kernel at LT stress and paving the way for simultaneous growth and LT stress responses.

QTL Mapping of Yield-Related Traits in Tetraploid Wheat Based on Wheat55K SNP Array.

To enhance the understanding of yield-related traits in tetraploid wheat, it is crucial to investigate and identify genes that govern superior yield characteristics. This study utilized the wheat55K single nucleotide polymorphism array to genotype a recombinant inbred line (RIL) population consisting of 120 lines developed through the crossbreeding of two tetraploid wheat varieties, Qin Hei-1 (QH-1) and Durum Wheat (DW). An investigation and analysis were conducted on 11 yield-related traits, including peduncle length (PL), neck length (NL), spike length (SL), flowering date (FD), heading date (HD), thousand-kernel weight (TKW), kernel area ratio (KAR), kernel circumference (KC), kernel length (KL), kernel width (KW), and kernel length-width ratio (KL-WR), over a period of three years in two locations, Yang Ling, Shaanxi, and Lin He, Inner Mongolia. The analysis identified nine stable loci among eight agronomic traits, named QSL.QD-1A.1, QNL.QD-4B.2, QPL.QD-4B.1, QFD.QD-2B, QHD.QD-2B.1, QHD.QD-4B, QKC.QD-4B.2, QKL-WR.QD-4B.6, and QKL.QD-4B.2. Among them, the additive effects of three QTLs, QSL.QD-1A.1, QNL.QD-4B.2, and QFD.QD-2B, were positive, indicating that the enhancing alleles at these loci were derived from the parent line QH-1. These three QTLs showed significant positive effects on the phenotypes of the population materials. Furthermore, potential functional genes were identified within the mapping intervals of QSL.QD-1A.1 and QNL.QD-4B.2, which regulate the development of spike length and neck length, respectively. These results provide potential QTLs and candidate genes, which broaden the genetic basis of agronomic traits related to yield, such as SL, NL, PL, and FD, and benefits for wheat breeding and improvement.