Wheat Lines Research Articles

Physiological and Transcriptome Analyses Provide Insights into the Response of Grain Filling to High Temperature in Male-Sterile Wheat (Triticum aestivum L.) Lines

Physiological and Transcriptome Analyses Provide Insights into the Response of Grain Filling to High Temperature in Male-Sterile Wheat (Triticum aestivum L.) Lines

Genetic mapping of QTLs for resistance to bacterial leaf streak in hexaploid wheat.

Robust QTLs conferring resistance to bacterial leaf streak in wheat were mapped on chromosomes 3B and 5A from the variety Boost and on chromosome 7D from the synthetic wheat line W-7984. Bacterial leaf streak (BLS), caused by Xanthomonas translucens pv. undulosa poses a significant threat to global wheat production. High levels of BLS resistance are rare in hexaploid wheat. Here, we screened 101 diverse wheat genotypes under greenhouse conditions to identify new sources of BLS resistance. Five lines showed good levels of resistance including the wheat variety Boost and the synthetic hexaploid wheat line W-7984. Recombinant inbred populations derived from the cross of Boost × ND830 (BoostND population) and W-7984 × Opata 85 (ITMI population) were subsequently evaluated in greenhouse and field experiments to investigate the genetic basis of resistance. QTLs on chromosomes 3B, 5A, and 5B were identified in the BoostND population. The 3B and 5A QTLs were significant in all environments, but the 3B QTL was the strongest under greenhouse conditions explaining 38% of the phenotypic variation, and the 5A QTL was the most significant in the field explaining up to 29% of the variation. In the ITMI population, a QTL on chromosome 7D explained as much as 46% of the phenotypic variation in the greenhouse and 18% in the field. BLS severity in both populations was negatively correlated with days to heading, and some QTLs for these traits overlapped, which explained the tendency of later maturing lines to have relatively higher levels of BLS resistance. Markers associated with the QTLs were converted to KASP markers, which will aid in the deployment of the QTLs into elite lines for the development of BLS-resistant wheat varieties.

Physicochemical properties of grain of promising winter durum wheat varieties and lines in the south of the Rostov region

The most important thing in the production of durum wheat is to obtain high-quality grain. In this regard, in the Rostov Region, there has been studied the physical and chemical properties of this crop and identified several sources for high-quality grain breeding. The objects of study were 30 winter durum wheat varieties and lines of our own breeding, with the standard variety ‘Kristella’. Large grain (1000-grain weight over 40 g) was formed by 12 winter durum wheat samples. According to the GOST, 26 varieties and lines (770–809 g/l) belonged to the 1st class of grain. In 2021–2023, grain hardness varied from 69 % to 93 %. This trait was influenced by weather conditions during the years of study, grain with large hardness (100 %) was formed in the favorable 2022, in 2023 the grain was floury (51 %). The protein percentage in grain varied over the years from 13.70% in 2022 to 14.91 % in 2021. The mean gluten content of winter durum wheat samples was consistently high over the years and ranged from 28.0 % (2022) to 30.1 % (2021). The mean carotenoid content over the years varied significantly from 472 μg/% (2023) to 718 μg/% (2021). There were significant fluctuations among the samples. Due to the diversity of weather conditions during the years of study, there have been identified 6 winter durum wheat varieties and lines ‘Diona’, ‘Dinas’, ‘Pridonie’, ‘691/20’, ‘390/20’, ‘1377/20’ according to the complex of physical and chemical properties.

Estimation of the development of androgenic dihaploid lines of winter wheat of the R1 generation in vivo

Development of dihaploid lines using biotechnological methods can reduce not only the time required to breed a new variety, but also labor costs and technical resources. Earlier in our studies, there has been obtained seed material of androgenic dihaploid of the regenerated plants of the R0 generation, grown ex vitro. The next stage of the work delt with sowing the seeds of these plants in vivo. The purpose of the current study was to estimate the development of winter wheat plants of androgenic dihaploid lines of the R1 generation and parental varieties in vivo according to such characteristics as a length of phenophases, a vegetation period, morphometric estimation for comparison with each other and with parental genotypes, as well as for seed propagation. As a result of the study carried out in 2022–2024, there has been estimated a new nitial material of winter common wheat obtained on the basis of previously conducted biotechnological work. There have been studied androgenic dihaploid R1 lines according to the traits of vegetative and generative organs, for grain productivity of plants and seed germination. There have been selected promising lines for further breeding evaluation. Androgenic dihaploid lines of winter wheat of the R1 generation 79.1.5.1, 79.1.5.2, 79.2.1.1, 84.3.1.1, 84.3.3.1, 85.2.1.1 were the best according to vegetative, generative traits, grain productivity and seed germination. The best indicators of productivity and germination were characterized by androgenic dihaploid lines based on the hybrid ‘Rostovchanka 7 x Bezostaya 100’.

Structural, molecular, and physicochemical properties of starch in high-amylose durum wheat lines

There is growing interest in the development of high-amylose cereals such as wheat due to their functional properties and nutritional value in foods. The increase in amylose content is associated with significant changes in the physicochemical, molecular, and structural characteristics of wheat starch which could affect its processing quality. The present study aimed to analyze the physicochemical, molecular, and structural characteristics of high-amylose starch from three durum wheat near isogenic lines (NILs), each obtained using three different recurrent parents. Morphology, granule size distribution, pasting and thermal properties, X-ray diffraction, and structural features were determined. The NILs showed the highest amylose content (65.3 and 69.8%), granules with an elongated shape, size between the wild-type and the mutant, restricted swelling in the pasting profile, the highest average and final gelatinization temperature, and B-polymorphism. The starches from the NILs showed the highest molar mass of amylopectin (AP) (7.0–7.6 × 107 Da) and the lowest amylose (AM) (1.1–1.8 × 106 Da), an issue associated with the biosynthesis of both components. The study on the debranched sample by high-performance size-exclusion chromatography showed that the high-amylose starch had the highest content of long B2 and B3 chains of AP (23.9–26.6%), which was corroborated with the high-performance anion-exchange chromatography analysis where the chains with degree of polymerization >37 had the highest content (18.3–19.1%). The PC1 is highly associated with the MwAM and the AM fraction in the debranched starch analyzed by HPSEC. Characterizing high-amylose durum wheat starch provides information to determine the structure-function relationship and design strategies to produce crosses with structural characteristics of AM and AP for specific applications.

Physiological phenotyping of transpiration response to vapour pressure deficit in wheat

BackgroundPrecision phenotyping of short-term transpiration response to environmental conditions and transpiration patterns throughout wheat development enables a better understanding of specific trait compositions that lead to improved transpiration efficiency. Transpiration and related traits were evaluated in a set of 79 winter wheat lines using the custom-built “DroughtSpotter XXL” facility. The 120 l plant growth containers implemented in this phenotyping platform enable gravimetric quantification of water use in real-time under semi-controlled, yet field-like conditions across the entire crop life cycle.ResultsThe resulting high-resolution data enabled identification of significant developmental stage-specific variation for genotype rankings in transpiration efficiency. In addition, for all examined genotypes we identified the genotype-specific breakpoint in transpiration in response to increasing vapour pressure deficit, with breakpoints ranging between 2.75 and 4.1 kPa.ConclusionContinuous monitoring of transpiration efficiency and diurnal transpiration patterns enables identification of hidden, heritable genotypic variation for transpiration traits relevant for wheat under drought stress. Since the unique experimental setup mimics field-like growth conditions, the results of this study have good transferability to field conditions.

Development and Characterization of Two Wheat-Rye Introgression Lines with Resistance to Stripe Rust and Powdery Mildew.

Rye (Secale cereale L.) genes, which contribute to the tertiary gene pool of wheat, include multiple disease resistance genes useful for the genetic improvement of wheat. Introgression lines are the most valuable materials for wheat breeding because of their small alien segments and limited or lack of linkage drag. In the present study, wheat-rye derivative lines SN21627-2 and SN21627-6 were produced via distant hybridization. A genomic in situ hybridization analysis revealed that SN21627-2 and SN21627-6 lack alien segments, while a multi-color fluorescence in situ hybridization analysis detected structural changes in both introgression lines. At the seedling and adult plant stages, SN21627-2 and SN21627-6 were highly resistant to stripe rust and powdery mildew. Primers for 86 PCR-based landmark unique gene markers and 345 rye-specific SLAF markers were used to amplify SN21627-2 and SN21627-6 genomic DNA. Eight markers specific to rye chromosome 2R were detected in both introgression lines, implying these lines carry chromosome 2R segments with genes conferring stripe rust and powdery mildew resistance. Therefore, SN21627-2 and SN21627-6 are resistant to more than one major wheat disease, making them promising bridging parents for breeding disease-resistant wheat lines.

Performance of bread wheat advanced lines under late sowing and hydric stress during the crop season 2020-2021

Thirty four advanced bread wheat lines and cultivar Borlaug 100 were sown on January 15 and 30, 2021, at the Norman E. Borlaug Experimental Station, in the Yaqui Valley, Sonora, México. Plots consisted of 1 bed 2 m long with two rows and 0.80 m apart with two replications, and a seed density of 100 kg ha-1 with two complementary irrigations. Average daily temperature (°C), maximum, minimum, relative humidity, rainfall, heat and cold units were recorded from January 1 to May 15, 2021. The average days for heading of the group was 69 for the first sowing date and 66 for the second one, while days for physiological maturity were 99 and 90, respectively. The average plant height of the group for the first date was 97.5 cm and 94 for the second one; the sister line SOKOLL/5/W15.92/4/PASTOR//HXL7573/2*BAU/3/ WBLL1/6/SOKOLL/3/PASTOR//HXL7573/2*BAU (PTSS12SHB00020T-0TOPB-099Y-099B-25Y-020Y-0B) consistently reached the maximum height with 107.5 and 110 cm in each date, respectively. The average grain yield per plot was 294 g; line BAJ #1*2/4/BETTY/3/CHEN/AE.SQ//2*OPATA showed the highest yield with 345.4 g which was above 4.3 t ha-1, followed by SOKOLL/3/PASTOR//HXL7573/2*BAU/4/ASTREB/5/PIHA//WORRAKATTA/2*PASTOR /3/PRL/2*PASTOR, also above 4.3 t ha-1. The average hourly temperature was 18.4 °C with a maximum of 40.8 °C and a minimum of 3.9 °C, and the number of heat and cold units was 203 and 393, respectively.

Identification of Resistance to <i>Puccinia striiformisf</i>. sp. <i>tritici</i> (<i>Pst</i>) in Some Commercial and Elite Bread Wheat Lines

Stripe rust is caused by <i>Puccinia striiformisf</i>. sp. <i>tritici</i> (<i>Pst</i>) threatening wheat production in Ethiopia. The emerged virulent stripe rust races at one point of the world spread to the rest of wheat-producing countries by the wind as well as human travels and damaged popular resistant wheat cultivars thereby posing food insecurity. However, wheat cultivars succumb to new Pst race (s) soon after their release from research centers. This study aimed to determine stripe rust resistance in some Ethiopian commercial and elite bread wheat lines. In 2017, a total of 37 commercial and elite bread wheat lines were exposed to stripe rust in under the disease hot spot areas (Kulumsa and Meraro) Arsi zone Oromia regional state. In the second year (2018), 22 promising lines consisting of 16 commercial bread wheat and 6 elite’s lines were evaluated both at seedling and adult plant growth stages. The seedling test was conducted in the greenhouse at Kulumsa research center using three Pst races. In field evaluations, terminal severity (TRS), coefficient of infection (CI), area under disease progress curve (AUDPC), disease progress rate (DPR), and spike infection (SI) were considered. Of the 37 commercial and elite bread wheat lines, 19 (51.4%) exhibited lower or equal disease reaction compared to the resistant check (Enjoy) across locations and seasons. Eleven bread wheat lines showed both adult plant and seedling resistance. The 37 commercial wheat lines that showed field resistance was further exposed to three Pst races at the seedling stage and 11 exhibited seedling resistance to all races. This study has identified seedling and adult plant resistance in some commercial and elite bread wheat lines to the prevailing Pst races.

Variability of Agronomic Traits of Wheat (Triticum aestivum L.) Lines in Two Agroecosystems in Indonesia

Wheat is an important agricultural commodity in Indonesia, yet the country remains heavily reliant on imports to meet domestic demand. The diverse agroclimatic conditions in the highlands and lowlands pose significant challenges for national wheat production. This study aimed to evaluate the performance of wheat lines in two distinct altitude environments: Cipanas (1120 m above sea level) and Cisarua (600 m above sea level). An augmented randomized complete block design (RCBD) assessed 50 F6 wheat lines derived from the HP1744/”Selayar” cross. The results revealed significant variability in agronomic traits attributable to altitude differences. However, genotype-by-environment (GxE) interactions were found to be non-significant for all evaluated characters. Broad-sense heritability was classified as medium for the grain-filling period in Cipanas and seed weight of the main panicle in Cisarua, while all other traits exhibited low heritability. Based on the stress sensitivity index (SSI), 14 lines (28%) were identified as tolerant to higher temperatures in the medium-altitude environment, particularly in terms of seed weight of the main panicle. These findings are of utmost importance as they underscore the need to consider genetic and environmental factors in developing wheat cultivars suitable for Indonesia’s diverse agro-climatic conditions.

Genome-wide mapping of quantitative trait loci conferring resistance to stripe rust in spring wheat line PI 660072.

Two major QTL for resistance to stripe rust were mapped on chromosome 2BL and 4BL in spring wheat PI 660072, and their KASP markers were developed. Stripe rust, caused by Puccinia striiformis f. sp. tritici (Pst), is one of the most devastating diseases of wheat worldwide. Identifying resistance genes is crucial for developing resistant cultivars to control the disease. Spring wheat PI 660072 (Triticum aestivum) has been identified to possess both adult-plant resistance (APR) and all-stage resistance (ASR) to stripe rust. To elucidate the genetic basis of the resistance in PI 660072, a mapping population consisting of 211 F5-F7 recombinant-inbred lines (RILs) was developed from a cross of PI 660072 with susceptible spring wheat Avocet S. The mapping population was phenotyped for stripe rust responses across five field environments from 2020 to 2022 and genotyped using the 15K SNP (single nucleotide polymorphism) array to map stripe rust resistance loci. The mapping population was also tested at the seedling stage with predominant Chinese Pst races CYR31, CYR32, CYR34 and PST-YX1-3-1 in the greenhouse. Stripe rust resistance genes were identified using the quantitative trait locus (QTL) mapping approach. Two QTL were identified with QYrPI660072.swust-2BL mapped on the long arm of chromosome 2B for ASR and QYrPI660072.swust-4BL on the long arm of chromosome 4B for APR. To facilitate marker-assisted selection breeding, Kompetitive allele specific PCR (KASP) markers, KASP-1269 for QYrPI660072.swust-2BL and KASP-3209 for QYrPI660072.swust-4BL, were developed. These markers could be used to introgress the effective resistance QTL into new wheat cultivars.

Virulence characterization of wheat stripe rust population in China in 2023

AbstractWheat stripe rust, caused by Puccinia striiformis f. sp. tritici (Pst), significantly impacts global wheat production, including China. Monitoring Pst virulence is crucial for disease management. This study used 18 Yr single‐gene isogenic lines of wheat to characterize the virulence of 2023 Pst collections in China. A total of 103 isolates were collected from 11 provinces, and 61 races were identified. Frequencies of virulence to the 18 Yr genes varied from 0% to 95.1%, with low frequencies (defined as less than 10%) to Yr85 (7.8%) and Yr10 (8.7%); moderate frequencies (10%–40%) to Yr24 (15.5%), Yr32 (16.5%), YrSP (37.9%) and Yr76 (37.9%); and high frequencies (>40%) to Yr7 (47.6%), Yr1 (68.0%), Yr9 (69.9%), Yr27 (69.9%), Yr17 (79.6%), Yr6 (89.3%), YrExp2 (92.2%), Yr43 (93.2%), Yr8 (95.1%) and Yr44 (95.1%). Yr6, Yr8, Yr17, Yr27, Yr43, Yr44 and YrExp2 have almost lost their effectiveness in all provinces, while Yr10, Yr24, Yr32 and Yr85 are effective in Hebei, Shandong, Shaanxi, Gansu and Anhui. No isolate was virulent to Yr5 or Yr15, indicating their effectiveness against Pst populations in China. The Pst isolates had a wide virulence spectrum ranging from 3 to 16 virulence factors, with an average of 9.5. Comparing 2023 to 2021, the PstCN‐040 and races sharing virulence to Yr1, Yr6, Yr7, Yr8, Yr9, Yr17, Yr43, Yr44 and YrExp2 predominated, with frequencies 16.4% and 25.2%. This study provides valuable information on the virulence composition of Pst populations in China, helping to guide the development of genetic resistance for wheat in China.

The use of the species Triticum petropavlovskyi Udacz. et Migusch. to expand the genetic diversity of spring bread wheat

Background. The species Triticum petropavlovskyi Udacz. et Migusch. has a number of positive traits, but has rarely been used in breeding programs to improve bread wheat cultivars. The introgression of genetic material from this species into the Triticum aestivum L. gene pool will not only expand the genetic diversity of bread wheat with a set of traits valuable for breeders, but also help to analyze the expression of genes from T. petropavlovskyi in a new genetic environment. Materials and methods. Spring bread wheat lines L163 and L164 produced with the participation of bread wheat cv. ‘Voevoda’ and an accession of T. petropavlovskyi were target materials of the study. Conventional methods were applied to perform phenological, phytopathological, genetic, and bread quality evaluations. Statistical processing of the resulting data was carried out using the Agros-2.10 software. Results. L163 and L164 were studied for their morphological and phenological indicators, resistance to pathogens, productivity, and grain quality. Differences in a number of traits between the lines and the recipient cultivar were observed. The introgression of the T. petropavlovskyi genetic material into bread wheat showed both positive and negative effects on some agronomic characteristics. L163 was identified for its resistance to the pathogens of leaf rust and powdery mildew, and tolerance to cereal aphids. It combined high productivity with an increased grain protein content compared to the recipient cultivar. In addition, this line demonstrated good rheological properties of its dough. Conclusion. Merging genetic materials from T. petropavlovskyi and bread wheat cv. ‘Voevoda’ made it possible to produce lines with a set of positive characteristics. The selected line, L163, combined effective resistance to a number of diseases, high grain productivity, and good breadmaking qualities, so it was included in the breeding process.

A major falling number locus on chromosome 4B governs resistance to pre-harvest sprouting in bread wheat line Soru#1

Pre-harvest sprouting (PHS) is a serious threat to wheat quality and occurs when maturing seeds on plants encounter substantial rain before harvest. In the present study, the genetics of PHS resistance were studied using a population of 131 recombinant inbred lines (RILs) from a cross between Soru#1 and Naxos. The population was genotyped with the Illumina 90 K and Axiom 35 K wheat SNP arrays and tested in field trials across two locations in Norway and one in China. Seed dormancy as a measure of sprouting damage was evaluated using germination index (GI) and falling number (FN). Days to heading, days to maturity, and plant height were also recorded to evaluate their potential impact on PHS. Thirteen PHS-related quantitative trait loci (QTL) were detected. The most consistent QTL for FN, contributed by Soru#1, on the long arm of chromosome 4B explained 10.0–19.2% of the phenotypic variation across trials. Other important PHS resistance QTL from Soru#1 detected on chromosome arms 2AL, 2BL, and 4BS, affected both GI and FN. Naxos carried favorable QTL alleles for PHS resistance on chromosome arm 4AS and the Phs1 allele on 4AL. The reduced height Rht-D1 and vernalization Vrn-A1 alleles were the major determinants of plant height and earliness; however, these traits had minimal impact on the genetic control of PHS resistance in this population. Thus, both parents contributed valuable alleles for improving PHS resistance in breeding programs.

Differences in the Virulence Between Local Populations of Puccinia striiformis f. sp. tritici in Southwest China.

The virulence analysis of Puccinia stiiformis f. sp. tritici (Pst), the cause of wheat stripe rust, is essential for predicting and managing the disease epidemic in Southwest China, where the wheat cultivation has significantly reduced in the past few decades due to the impact of this disease. From 2020 to 2021, 196 Pst isolates were collected from Guizhou, Yunnan, and Sichuan. The virulence and race assessments were conducted using Chinese differential genotypes. Additionally, the resistance expression of 102 wheat lines was evaluated in 2021 in two disease nurseries located in Ningnan and Jiangyou. All the 45 Pst isolates from Guizhou and Yunnan belonged to pathogroup Hybrid 46, with 36 identified as race CYR32. Among the 69 isolates from the Liangshan Prefecture, 67 belonged to the Hybrid 46 group, while the remaining two were identified as race CYR34 in the G-22 group. Furthermore, all 79 isolates from the western Sichuan Basin belonged to the G-22 group, with 54 identified as race CYR34. The diversity indices of the Pst populations from Guizhou, Sichuan, and Yunnan exhibited a sequential decline. Virulence variation among the Pst populations from Yunnan, Guizhou, and the Ganzi-Liangshan region was minimal; however, significant virulence differences were observed when these populations were compared to those from the western Sichuan Basin. Results from disease nurseries indicated that Pst virulence was notably stronger in Ningnan compared to that in Jiangyou. The Sichuan Basin exhibits a notable diversity in Pst virulence, coupled with a more frequent genetic exchange occurring between the Liangshan Prefecture and the Yunnan-Guizhou Plateau. This information is essential for developing effective management strategies to mitigate the impact of wheat stripe rust in this region.

Variability of protein and gluten content in bread wheat lines with introgressions into chromosome 5B from related species

Variability of protein and gluten content in bread wheat lines with introgressions into chromosome 5B from related species

The first assessment of grain yield and associated traits in durum wheat across a decade in Nepal.

Rapid urbanization and evolving dietary preferences have heightened the demand for durum wheat and its derivatives in developing nations like Nepal. This study represents the first comprehensive exploration and evaluation of durum wheat genotypes in Nepal, addressing the escalating need for high-yielding varieties. The primary objective was to identify stable and prolific durum wheat lines for release, enhancing Nepal's durum wheat breeding program. Utilizing genotypes from CIMMYT's disease screening and yield nurseries from 2011/12 to 2020/21, a total of 132 genotypes, including international checks, underwent evaluation over ten years under the Alpha Lattice design. Results revealed significant variation among genotypes for grain yield and other traits, identifying high-yielding and stable lines suitable for Nepal. Heritability analysis highlighted moderate heritability for grain number per spike, thousand-grain weight, and grain yield. Cluster analysis identified distinct clusters with high grain yield and desirable agronomic traits. Disease incidence facilitated the selection of resistant lines, with DWK38 emerging as the highest grain yielder (4416.04 kg/ha). Overall, durum wheat lines from CIMMYT exhibited robust performance in Nepal, enabling the identification of superior lines with potential benefits for farmers and consumers. The study's implications include developing and releasing superior durum lines in Nepal, providing farmers with profitable alternatives amidst evolving food habits. In conclusion, the findings from this study provide a valuable foundation for future durum wheat breeding efforts in Nepal, guiding the selection of genotypes that are well-suited to the diverse environmental challenges of the region.

Accelerating genetic gain through strategic speed breeding in spring wheat

AbstractSpring wheat (Triticum aestivum L.) is a popular bread wheat with high milling and baking requirements. Vernalization is not required for spring wheat, which allows for fast growth under manipulated conditions. This experiment's objective was rapid development of inbred lines of hard red spring wheat throughout the off‐season and preserve enough genetic variability to perform selection. A total of 1575 F2 heads from three distinct populations were randomly harvested in the field‐season 2021. To break seed dormancy, seeds were held for 2 days at 0°C. Three breeding cycles were performed through single seed descent under manipulated growth condition during the off‐season 2021–2022. We were able to harvest plant materials as quickly as 54 days after planting in comparison to 110 days average field season. We lost a total of 36.4% during the three off‐season fast advancement generations and 711 genotypes reached the F5:6 generation with enough seed to perform a partially replicated small plot yield trial at two locations during the 2022 field‐season. Response traits collected included grain yield, grain protein, plant height, days to heading, and bacterial leaf streak (Xanthomonas transluens) disease severity. Heritability of collected traits varied between 0.61 and 0.92. Although we had considerable loss during the speed breeding, we were able to identify superior genotypes compared to the parents.

Assessment of genetic variability, heritability and correlation in advanced breeding lines of bread wheat (Triticum aestivum) under heat stress condition

Abstract An experiment was conducted under normal (with six irrigation during crop period) and stressed condition during Rabi 2019 in All India Coordinated Research Project (AICRP) on Wheat, MARS, Dharwad, Karnataka with the view of assessing genetic variability, heritability and expected genetic advance in 104 F4 families of the cross HD2864 × DBW14. The progenies exhibited wide range of variation for all the traits indicating the presence of enough genetic variability in the material under study. Under timely sown condition, the traits like leaf waxyness, NDVI at different stages, SPAD at different stages, number of productive tillers per plant, seeds per spike, grain filling duration, spike length, thousand grains weight and seed set percentage showed high variability. The traits like plant height, canopy temperature at different stages and membrane stability index showed low variability. Under late sown condition, the traits like leaf waxyness, plant height, NDVI at different stages, SPAD at different stages, number of productive tillers per plant, seeds per spike, yield per plant, row bulk yield and seed set percentage showed high variability. The traits like days to maturity, spike length and membrane stability index showed low variability. The findings shows that all traits related to crop yield are positively linked, except for canopy temperature at different growth stages. Promising lines identified through Heat susceptibility index (HSI) and Heat tolerance index (HTI) can be utilized in future breeding programs to enhance crop productivity. Keywords: Variability, Coefficient of variation, Heritability, Genetic advance.

Exploring the rhizosphere of perennial wheat: potential for plant growth promotion and biocontrol applications

Perennial grains, which remain productive for multiple years, rather than growing for only one season before harvest, have deep, dense root systems that can support a richness of beneficial microorganisms, which are mostly underexplored. In this work we isolated forty-three bacterial strains associated with the rhizosphere of the OK72 perennial wheat line, developed from a cross between winter common wheat and Thinopyrum ponticum. Identified using 16S rDNA sequencing, these bacteria were assessed for plant growth-promoting traits such as indole-3-acetic acid, siderophores and ACC-deaminase acid production, biofilm formation, and the ability to solubilize phosphate and proteins. Twenty-five strains exhibiting in vitro significant plant growth promoting traits, belong to wheat keystone genera Pseudomonas, Microbacterium, Variovorax, Pedobacter, Dyadobacter, Plantibacter, and Flavobacterium. Seven strains, including Aeromicrobium and Okibacterium genera, were able to promote root growth in a commercial annual wheat cultivar while strains from Pseudomonas genus inhibited the growth of Aspergillus flavus and Fusarium species, using direct antagonism assays. The same strains produced a high amount of 1-undecanol a volatile organic compound, which may aid in suppressing fungal growth. The study highlights the potential of these bacteria to form new commercial consortia, enhancing the health and productivity of annual wheat crops within sustainable agricultural practices.