Elite Cultivars Research Articles

IGKM 05-18-2: identified as high yielding and multiple disease resistance rabi mungbean genotype for Chhattisgarh state

To enhance the yield potential in the rabi season, a high yielding and multiple disease resistant mungbean genotype, IGKM 05-18-2 has been developed through pedigree method from cross between Pairy Mung x Pusa Vishal at IGKV, Raipur, Chhattisgarh. The entry was tested in multilocation trial (12 locations) for three years (2017-18 to 2019-20) followed by testing in All India Coordinated Research Project on MULLaRP for a period of two years (2019-20 and 2020-21). It was also screened for various pests and diseases under pathological trials of AICRIP. Based on three years data (2017-18 to 2019-20) in state multilocation trials, during Rabi season, the entry IGKM 05-18-2 (902.40 Kg ha-1) had shown 8.29 % yield increase over the best check i.e. Pairy Mung (833.27 Kg ha-1). Likewise, under All India Coordinated Research Project (AICRP on MULLaRP) this entry shown the 6.46 % yield advantage over the best check VBN 4 based on the mean performance in IVT and AVT-1 trials. In addition to the yield advantages, it shown multiple resistances to MYMV, Cercospora leaf spot, Powdery mildew and root rot in co-ordinated trials whereas, it was found resistant against PM, MYMV and Alternaria leaf spot at station trial. The entry IGKM 05-18-2 showed moderate insect pest infestation and was considered as promising entry. The entry IGKM 05-18-2 was found with moderate insect pest (thrips, whiteflies and maruca pod borer) infestation and considered as promising entry and the higher seed yield was recorded than Local check LGG 450. The data of the tested entry revealed the mungbean genotype, IGKM 05-18-2 is found to have high yield potential, multiple disease resistant and most suitable for cultivation in rabi season of the state. This improved line with enhanced resistance for multiple diseases can also be further used as a resistant donor for transfer disease resistance genes in other elite cultivars.

Fine mapping of powdery mildew resistance gene PmXNM in a Chinese wheat landrace Xiaonanmai.

Powdery mildew resistance gene PmXNM, originated from the Chinese wheat landrace Xiaonanmai, was delimited to a 300.7-kb interval enriched with resistance genes. Powdery mildew, caused by Blumeria graminis f. sp. tritici (Bgt), is a globally devastating disease threatening the yield and quality of wheat worldwide. The use of broad-spectrum disease resistance genes from wheat landraces is an effective strategy to prevent this pathogen. Chinese wheat landrace Xiaonanmai (XNM) was immune to 23 tested Bgt isolates at the seedling stage. The F1, F2, and F2:4 progenies derived from the cross between XNM and Chinese Spring (CS) were used in this study. Genetic analysis revealed that powdery mildew resistance in XNM was controlled by a single dominant gene, temporarily designated PmXNM. Bulked segregant analysis and molecular mapping delimited PmXNM to the distal terminal region of chromosome 4AL flanked by markers caps213923 and kasp511718. The region carrying the PmXNM locus was approximately 300.7kb and contained nine high-confidence genes according to the reference genome sequence of CS. Five of these genes, annotated as disease resistance RPP13-like proteins 1, were clustered in the target region. Haplotype analysis using the candidate gene-specific markers indicated that the majority of 267 common wheat accessions (75.3%) exhibited extensive gene losses at the PmXNM locus, as confirmed by aligning the targeted genome sequences of CS with those of other sequenced wheat cultivars. Seven candidate gene-specific markers have proven effective for marker-assisted introgression of PmXNM into modern elite cultivars.

Genetic Relatedness in Elite Cultivars of Moth Bean using Morpho-agronomic and Molecular Markers

Background: Moth bean is a very nutritive and hardy crop, especially for resource poor-arid agriculture. The limited use of cultivars in moth bean breeding resulted into narrow genetic base. This study aimed to diversify the conical genetic base and developimproved cultivars, through molecular (RAPD) and morpho-agronomic characterization of commercially elite moth bean cultivars. Methods: Elite moth bean cultivars (15) were evaluated for 11 morpho-agronomic traits. Eleven RAPD markers were used to amplify genomic DNA and perform molecular characterization.Clustering approach was used for grouping of the cultivars. Result: RAPD markers revealed high polymorphism in 15 elite moth bean cultivars. The polymorphism information content (PIC) values varied within the range of 0.45 to 0.88, with an average of 0.77. The number of alleles at different loci ranged from 4 to 16, with an average of 10 alleles per locus. When employing UPGMA-based cluster analysis, utilizing 11 morpho-agronomic traits, the cultivars were grouped into four clusters. However, when RAPD markers were used, the cultivars were grouped into five clusters. The Jaccard’s similarity coefficient and Manhattan dissimilarity coefficient fell within the ranges of 0.18 to 0.70 and 0.02 to 0.42, respectively. These values signify the degree of genetic variability within the cultivars. Furthermore, a Mantel test was conducted to examine the correlation between agronomic traits and the RAPD-based matrix. The results showed a negative correlation, but it was not statistically significant.The high PIC values and the successful amplification of multiple loci demonstrate the efficacy of RAPD markers in assessing genetic diversity in moth beans. The study revealed enormous genetic variation among cultivars and crosses can be attempted between cultivars of different groups to create better recombinants in moth bean breeding programmes.

Modulation of the nutritional and functional values of common bean by farming system: organic vs. conventional

Common bean (Phaseolus vulgaris L.) is a crop of high nutritional interest which is widespread throughout the world as a result of which it is considered as a potential crop for ensuring future food security. The effect of organic and conventional farming systems on the nutritional and functional composition of two cultivars of market class fabada (a landrace and a modern elite cultivar) is described. The findings of our study have shown that the common beans from organic farming have a higher content of protein, phenolic compounds, and relevant microelements such as iron and zinc than the seeds from conventional farming trial. However, in conventional crops a higher content of polyunsaturated fatty acids and lower concentrations of phytic acid and raffinose oligosaccharides were also detected. In contrast, no significant differences were detected in the proximate composition of the two genotypes tested, nor in their antioxidant activity or levels of phenolic compounds. The elite cultivar maintains the nutritional characteristics of the landrace from which it derives, suggesting the genomic regions modified in the improvement do not play an important role in their genetic control.

Multivariate Analysis Compares and Evaluates Heat Tolerance of Potato Germplasm.

High temperature is the most important environmental factor limiting potato (Solanum tuberosum L.) yield. The tuber yield has been used to evaluate the heat tolerance of some potato cultivars, but potato yield was closely correlated with the maturation period. Therefore, it is necessary to employ different parameters to comprehensively analyze and evaluate potato tolerance to heat stress. This study aimed to investigate physiologic changes during growth and development, and develop accurate heat tolerance evaluation methods of potato cultivars under heat stress. About 93 cultivars (including foreign elite lines, local landraces and cultivars) were screened using an in vitro tuber-inducing system (continuous darkness and 8% sucrose in the culture medium) under heat stress (30 °C) and normal (22 °C) conditions for 30 days. The tuber yield and number decreased significantly under heat stress compared to the control. A total of 42 cultivars were initially selected depending on tuber formation, after in vitro screening, further testing of selected cultivars was conducted in ex vitro conditions. The screened cultivars were further exposed to heat stress (35 °C/28 °C, day/night) for 60 days. Heat stress led to an increase in the plant height growth rate, fourth internode growth rate, and membrane damage, and due to heat-induced damage to chloroplasts, decrease in chlorophyll biosynthesis and photosynthetic efficiency. Three principal components were extracted by principal component analysis. Correlation and regression analysis showed that heat tolerance is positively correlated with the plant height growth rate, fourth internode growth rate, the content of chlorophyll b, photosynthetic rate, stomatal conductance, transpiration rate, tuber number, and tuber yield, and negatively correlated with the cell membrane injury level. The nine traits are accurate and representative indicators for evaluating potato tolerance to heat stress and could determine a relatively high mean forecast accuracy of 100.0% for the comprehensive evaluation value. Through cluster analysis and screening, cultivar FA, D73, and C132 had the highest heat comprehensive evaluation value, which could be further selected as heat-resistant varieties. This study provides insights into the different physiological mechanisms and accurate evaluation methods of potato cultivars under heat stress, which could be valuable for further research and breeding.

Identification of High-Yielding Soybean Lines with Exceptional Seed Composition Qualities

In current markets, the primary uses for soybean seeds are in products derived from their oil or protein content. However, growers are compensated based on seed yield, so a more valuable crop is one that does not compromise on yield when compared with existing options, with an optimum combination of protein and oil. A negative correlation of seed protein with seed yield and oil makes the simultaneous improvement of these traits difficult but not impossible through conventional breeding. Selections of lines with exceptional yield and seed composition were made from two recombinant inbred line (RIL) soybean mapping populations to identify high protein and/or high oil lines with yields comparable to elite cultivars. The performance of these RILs was evaluated in multiple environments, and several genotypes were identified with yields comparable to those of high-yielding check cultivars with seed protein and/or oil content superior to the checks. These genotypes will provide breeders with additional sources of germplasm for continuing efforts to improve seed composition traits without compromising seed yield and provide growers with more profitable cultivars.

Development of Allium cepa potential intron polymorphism markers for molecular breeding of Alliums

Allium cepa is a widely grown crop for its spice and culinary properties. For molecular breeding of Allium cepa, mining and utilization of various sequence-based markers have been widely reported. Unfortunately, none has reported its molecular breeding using potential intron polymorphism (PIP) markers. Due to advantage of intron positioning prediction and practical utility, the PIP markers used for screening the possible polymorphism and cross-transferability in the Alliums. Screening results showed that among 500 Allium cepa potential intron polymorphism (AcPIP) markers, 275 are cross-transferable and polymorphic. Among the 275 AcPIP, 111 polymorphic markers were physically mapped on to 1st to 8th chromosomes of the Allium cepa. Out of the 275 AcPIP containing functionally significant markers, 118 were mapped in onion with Arabidopsis proteome. A set of 10 Alliums were utilized to interpret the polymorphic possibilities of the 500 AcPIP markers. In totality, 55 % AcPIP markers were polymorphic and cross-transferable among the Alliums. The polymorphic information content (PIC) of AcPIP markers ranged from 0.03 to 0.47 and heterozygosity index (H) varied between 0.16 and 0.80. The constructed phylogenetic tree based on the AcPIP markers of 10 Alliums revealed different clusters due to differences in their taxonomic positions. Out of 275 AcPIP markers, 10 AcPIP markers genotyping based Jaccard dissimilarity-based NJ tree of 96 individuals of Allium cepa showed two distinct groups (high total soluble solid; HTSS and low total soluble solid; LTSS). NJ tree and dissimilarity matrix reveal that group I genotypes are distinct, and dissimilar from group II and III genotypes hence it seems that group II and III genotype evolve from group I genotypes. Further we identified nine diverse Allium cepa subsample among which, genotype number 74 has HTSS and could be used for identification and introgression of HTSS coding genes in elite cultivars. Further DNA fingerprint of Alliums with 20 AcPIP markers suggested geographical reach of the released onion varieties. Hence results suggest that 275 AcPIP markers may be useful for accelerating the breeding programme of the Alliums and other species.

Morphological, phytochemical and genetic characterization of Centella asiatica accessions collected throughout Vietnam and Laos

Pennywort (Centella asiatica L.) is commonly grown in the tropical world for its nutritional and medicinal values. Valuable saponins in pennywort are extensively investigated for their anti-tumour activities. The diversity in morphology, phytochemical contents and genetics among pennywort accessions has been extensively studied to identify elite landraces for large-scale production. While pennywort is widely consumed in Vietnam, a systematic characterization of their diverse morphology, secondary metabolites and genetics is lacking. In this work, 26 pennywort accessions were collected across Vietnam and Laos. Their morphological features and yields were characterized under uniform agro-climatic conditions at Hue city in central Vietnam. The highest yield was obtained with HUIB_CA20 (478 g per tray), compared to the lowest yield in HUIB_CA19 (107 g per tray). Furthermore, a range of phytochemical markers, including vitamin C, reducing sugar, carotenoid, tannin, phenolic, flavonoid and saponin contents, were determined. Based on yield, phenolic and flavonoid contents, HUIB_CA20 and HUIB_CA27 were determined to be elite cultivars in this germplasm. Finally, microsatellite analysis was performed to explore the genetic diversity within the germplasm. Using fourteen SSR primer pairs, a total of 47 alleles were identified with 45 alleles (96 %) being polymorphic. These results will be useful for breeding programs aiming to create elite pennywort cultivars with enhanced properties.

Soybean reduced internode 1 determines internode length and improves grain yield at dense planting

Major cereal crops have benefitted from Green Revolution traits such as shorter and more compact plants that permit high-density planting, but soybean has remained relatively overlooked. To balance ideal soybean yield with plant height under dense planting, shortening of internodes without reducing the number of nodes and pods is desired. Here, we characterized a short-internode soybean mutant, reduced internode 1 (rin1). Partial loss of SUPPRESSOR OF PHYA 105 3a (SPA3a) underlies rin1. RIN1 physically interacts with two homologs of ELONGATED HYPOCOTYL 5 (HY5), STF1 and STF2, to promote their degradation. RIN1 regulates gibberellin metabolism to control internode development through a STF1/STF2–GA2ox7 regulatory module. In field trials, rin1 significantly enhances grain yield under high-density planting conditions comparing to its wild type of elite cultivar. rin1 mutants therefore could serve as valuable resources for improving grain yield under high-density cultivation and in soybean–maize intercropping systems.

Wheat stripe rust resistance locus YR63 is a hot spot for evolution of defence genes – a pangenome discovery

BackgroundStripe rust, caused by Puccinia striiformis f. sp. tritici (Pst), poses a threat to global wheat production. Deployment of widely effective resistance genes underpins management of this ongoing threat. This study focused on the mapping of stripe rust resistance gene YR63 from a Portuguese hexaploid wheat landrace AUS27955 of the Watkins Collection.ResultsYR63 exhibits resistance to a broad spectrum of Pst races from Australia, Africa, Asia, Europe, Middle East and South America. It was mapped to the short arm of chromosome 7B, between two single nucleotide polymorphic (SNP) markers sunCS_YR63 and sunCS_67, positioned at 0.8 and 3.7 Mb, respectively, in the Chinese Spring genome assembly v2.1. We characterised YR63 locus using an integrated approach engaging targeted genotyping-by-sequencing (tGBS), mutagenesis, resistance gene enrichment and sequencing (MutRenSeq), RNA sequencing (RNASeq) and comparative genomic analysis with tetraploid (Zavitan and Svevo) and hexaploid (Chinese Spring) wheat genome references and 10+ hexaploid wheat genomes. YR63 is positioned at a hot spot enriched with multiple nucleotide-binding and leucine rich repeat (NLR) and kinase domain encoding genes, known widely for defence against pests and diseases in plants and animals. Detection of YR63 within these gene clusters is not possible through short-read sequencing due to high homology between members. However, using the sequence of a NLR member we were successful in detecting a closely linked SNP marker for YR63 and validated on a panel of Australian bread wheat, durum and triticale cultivars.ConclusionsThis study highlights YR63 as a valuable source for resistance against Pst in Australia and elsewhere. The closely linked SNP marker will facilitate rapid introgression of YR63 into elite cultivars through marker-assisted selection. The bottleneck of this study reinforces the necessity for a long-read sequencing such as PacBio or Oxford Nanopore based techniques for accurate detection of the underlying resistance gene when it is part of a large gene cluster.

Gene mining and genomics-assisted breeding empowered by the pangenome of tea plant Camellia sinensis.

Tea is one of the world's oldest crops and is cultivated to produce beverages with various flavours. Despite advances in sequencing technologies, the genetic mechanisms underlying key agronomic traits of tea remain unclear. In this study, we present a high-quality pangenome of 22 elite cultivars, representing broad genetic diversity in the species. Our analysis reveals that a recent long terminal repeat burst contributed nearly 20% of gene copies, introducing functional genetic variants that affect phenotypes such as leaf colour. Our graphical pangenome improves the efficiency of genome-wide association studies and allows the identification of key genes controlling bud flush timing. We also identified strong correlations between allelic variants and flavour-related chemistries. These findings deepen our understanding of the genetic basis of tea quality and provide valuable genomic resources to facilitate its genomics-assisted breeding.

CRISPR/Cas as a Genome-Editing Technique in Fruit Tree Breeding

CRISPR (short for “Clustered Regularly Interspaced Short Palindromic Repeats”) is a technology that research scientists use to selectively modify the DNA of living organisms. CRISPR was adapted for use in the laboratory from the naturally occurring genome-editing systems found in bacteria. In this work, we reviewed the methods used to introduce CRISPR/Cas-mediated genome editing into fruit species, as well as the impacts of the application of this technology to activate and knock out target genes in different fruit tree species, including on tree development, yield, fruit quality, and tolerance to biotic and abiotic stresses. The application of this gene-editing technology could allow the development of new generations of fruit crops with improved traits by targeting different genetic segments or even could facilitate the introduction of traits into elite cultivars without changing other traits. However, currently, the scarcity of efficient regeneration and transformation protocols in some species, the fact that many of those procedures are genotype-dependent, and the convenience of segregating the transgenic parts of the CRISPR system represent the main handicaps limiting the potential of genetic editing techniques for fruit trees. Finally, the latest news on the legislation and regulations about the use of plants modified using CRISPR/Cas systems has been also discussed.

Nutritional Composition, Mineral Profiling, In Vitro Antioxidant, Antibacterial and Enzyme Inhibitory Properties of Selected Indian Guava Cultivars Leaf Extract.

Psidium guajava L. is a small evergreen tree known for its magnificent medicinal and nutritional value. This study aimed to evaluate the nutritional profile and in vitro pharmacological potentialities of the different leaf extracts of four cultivars of Psidium guajava namely Surka chitti, Allahabad safeda, Karela, and Lucknow-49. The standard procedures of the Association of Official Analytical Chemists (AOAC) were followed to carry out the nutritional analysis and all of the cultivars recorded the presence of elements at a nominal range. The highest presence of phenols (125.77 mg GAE/g) and flavonoids (92.38 mg QE/g) in the methanolic leaf extract of the Karela cultivar was recorded. A wide range of minerals such as sodium, phosphorus, magnesium, zinc, and boron were recorded with a higher percentage in the Karela cultivar of Psidium guajava. In the enzyme inhibitory assays, Allahabad safeda showed potential inhibition with an IC50 of 113.31 ± 1.07, 98.2 ± 0.66 and 95.73 ± 0.39 μg/mL in α-amylase, α-glucosidase, and tyrosinase inhibition assays, respectively. The strong antioxidant effect was established by Lucknow-49 (IC50 of 74.43 ± 1.86 μg/mL) and Allahabad safeda (IC50 of 78.93 ± 0.46 μg/mL) for ABTS and DPPH assays, respectively. The ethyl acetate and methanolic leaf extracts of the Allahabad safeda cultivar showed better inhibition against Pseudomonas aeruginosa with an MIC of 14.84 and 28.69 µg/mL, respectively. A decent mean zone of inhibition was recorded in methanolic leaf extract that ranged from 21-25 mm in diameter against the tested bacterial strains (Proteus vulgaris, Bacillus subtilis, and P. aeruginosa). This is the first scientific report on the comparative and comprehensive analysis of indigenous guava cultivars to evidently shortlist the elite cultivars with enriched dietary nutrition and biological activities.

Untapped Sources of Dual Resistance to Hessian Fly and Greenbug in Synthetic Hexaploid Wheats.

The Hessian fly (Hf) and greenbugs (Gb) are major pests of wheat, causing severe economic losses globally. Deploying resistant wheat is the most effective strategy for managing these destructive insects. However, the resistance is not effective against all Hf or Gb biotypes and can impose selection pressure on insects, resulting in the development of virulent biotypes. These challenges must be met through the discovery of new and novel sources of resistance to these pests. Synthetic Hexaploid Wheat (SHW)-developed cultivars are a rich source of resistance against a diverse array of pathogens and pests. In this study, 80 SHW lines were evaluated for their resistance to Hf and Gb under controlled environmental conditions. Of these, a total of 36 SHW lines showed resistance independently to Hf biotype L and Gb biotype E, while 27 lines showed combined resistance to both Hf and Gb. Further, a subset of 10 SHW lines showed resistance to additional Hf biotypes, Great Plains and vH13. The identification of SHW lines resistant to multiple insects and biotypes offers an invaluable resource to breeders who are looking to stack resistance traits to develop elite cultivars as a strategy to alleviate economic impacts upon global wheat production.

Skipping irrigation at pre- and post-anthesis stages influences grain yield and starch contents of bread wheat derived from synthetic or landraces

This study aims to evaluate the role of genetic diversity originated from three-way crosses of landraces and synthetic bread wheat derivatives attempted with elite cultivars to identify the genotypes having better grain yield as well as better starch contents under flowering stage drought stress. In total, 50 genotypes comprised of 47 derivatives of landraces and synthetics, and three standard varieties were grown in the fields of CIMMYT, Obregon following alpha lattice design with two replications. Drought stress was imposed by stopping the irrigation before anthesis and post-anthesis stages. Different traits related to physiological adaptations, earliness, grain yield and starch contents were decreased under drought stress except amylose which increased significantly. Canopy temperature depression was not significantly affected by drought stress. Further, we identified strong correlation of grain yield with plant height, normalized difference in vegetation index, plant maturity, spike length, grain number and thousand grain weight but negative with canopy temperature depression. Non-significant correlation of amylose and amylopectin was recorded with grain yield. Results revealed that genetic diversity derived from landraces and synthetic bread wheat can improve grain yield and starch contents but simultaneous improvement of both is elusive.

Fine-tuning rice heading date through multiplex editing of the regulatory regions of key genes by CRISPR-Cas9.

Heading date (or flowering time) is a key agronomic trait that affects seasonal and regional adaption of rice cultivars. An unoptimized heading date can either not achieve a high yield or has a high risk of encountering abiotic stresses. There is a strong demand on the mild to moderate adjusting the heading date in breeding practice. Genome editing is a promising method which allows more precise and faster changing the heading date of rice. However, direct knock out of major genes involved in regulating heading date will not always achieve a new germplasm with expected heading date. It is still challenging to quantitatively adjust the heading date of elite cultivars with best adaption for broader region. In this study, we used a CRISPR-Cas9 based genome editing strategy called high-efficiency multiplex promoter-targeting (HMP) to generate novel alleles at cis-regulatory regions of three major heading date genes: Hd1, Ghd7 and DTH8. We achieved a series of germplasm with quantitative variations of heading date by editing promoter regions and adjusting the expression levels of these genes. We performed field trials to screen for the best adapted lines for different regions. We successfully expanded an elite cultivar Ningjing8 (NJ8) to a higher latitude region by selecting a line with a mild early heading phenotype that escaped from cold stress and achieved high yield potential. Our study demonstrates that HMP is a powerful tool for quantitatively regulating rice heading date and expanding elite cultivars to broader regions.

Assessment of growth and early maturation traits in various genotypes of muskmelon (Cucumis melo L.)

The success of any breeding programs depends on the parents chosen. Breeders select parents with high mean values as an added benefit for crossing programmes. The present investigation was carried out to evaluate the performance of muskmelon genotypes for growth and earliness attributes. Muskmelon (Cucumis melo L.) is one of the most well-known desert vegetables, belong to the Cucurbitaceae family. Thirty-three germplasm lines were collected from different regions of India. The experiment was conducted at Puthur village, Salem district, and evaluated under Randomised Block Design with three replications during February to May 2022. The findings indicate that the genotypes CM 2, CM 16, CM 11, CM 19, CM 7, CM 13 and CM 22 reported as elite genotypes were exhibited higher values for different traits like days to first female flower opening, first female flowering node, number of vines per plant, vine length (cm), sex ratio and days to first fruit harvest. As a result, the above mentioned seven genotypes are used in the hybridization programme, could be exploited to develop elite cultivars with maximum growth and earlier in flowering and harvest.

Genome-wide association analysis of tan spot disease resistance in durum wheat accessions from Tunisia.

Background: Tunisia harbors a rich collection of unexploited durum wheat landraces (Triticum durum ssp. durum) that have been gradually replaced by elite cultivars since the 1970s. These landraces represent an important potential source for broadening the genetic background of elite durum wheat cultivars and for the introgression of novel genes for key traits, including disease resistance, into these cultivars. Methods: In this study, single nucleotide polymorphism (SNP) markers were used to investigate the genetic diversity and population structure of a core collection of 235 durum wheat accessions consisting mainly of landraces. The high phenotypic and genetic diversity of the fungal pathogen Pyrenophora tritici-repentis (cause of tan spot disease of wheat) in Tunisia allowed the assessment of the accessions for tan spot resistance at the adult plant stage under field conditions over three cropping seasons. A genome-wide association study (GWAS) was performed using a 90k SNP array. Results: Bayesian population structure analysis with 9191 polymorphic SNP markers classified the accessions into two groups, where groups 1 and 2 included 49.79% and 31.49% of the accessions, respectively, while the remaining 18.72% were admixtures. Principal coordinate analysis, the unweighted pair group method with arithmetic mean and the neighbor-joining method clustered the accessions into three to five groups. Analysis of molecular variance indicated that 76% of the genetic variation was among individuals and 23% was between individuals. Genome-wide association analyses identified 26 SNPs associated with tan spot resistance and explained between 8.1% to 20.2% of the phenotypic variation. The SNPs were located on chromosomes 1B (1 SNP), 2B (4 SNPs), 3A (2 SNPs), 3B (2 SNPs), 4A (2 SNPs), 4B (1 SNP), 5A (2 SNPs), 5B (4 SNPs), 6A (5 SNPs), 6B (2 SNPs), and 7B (1 SNP). Four markers, one on each of chromosomes 1B, and 5A, and two on 5B, coincided with previously reported SNPs for tan spot resistance, while the remaining SNPs were either novel markers or closely related to previously reported SNPs. Eight durum wheat accessions were identified as possible novel sources of tan spot resistance that could be introgressed into elite cultivars. Conclusion: The results highlighted the significance of chromosomes 2B, 5B, and 6A as genomic regions associated with tan spot resistance.

Development and Genome-Wide Analysis of a Blast-Resistant japonica Rice Variety.

Rice is one of the most important crops in the world, and its production is severely affected by the rice blast disease caused by the fungus Magnaporthe oryzae. Several major blast resistance genes and QTLs associated with blast resistance have been described and mostly identified in indica rice varieties. In this work, we report the obtention of a blast-resistant rice breeding line derived from crosses between the resistant indica variety CT13432 and the japonica elite cultivar JSendra (highly susceptible to blast). The breeding line, named COPSEMAR9, was found to exhibit resistance to leaf blast and panicle blast, as demonstrated by disease assays under controlled and field conditions. Furthermore, a high-quality genome sequence of the blast-resistant breeding line was obtained using a strategy that combines short-read sequencing (Illumina sequencing) and long-read sequencing (Pacbio sequencing). The use of a whole-genome approach allowed the fine mapping of DNA regions of indica and japonica origin present in the COPSEMAR9 genome and the identification of parental gene regions potentially contributing to blast resistance in the breeding line. Rice blast resistance genes (including Pi33 derived from the resistant parent) and defense-related genes in the genome of COPSEMAR9 were identified. Whole-genome analyses also revealed the presence of microRNAs (miRNAs) with a known function in the rice response to M. oryzae infection in COPSEMAR9, which might also contribute to its phenotype of blast resistance. From this study, the genomic information and analysis methods provide valuable knowledge that will be useful in breeding programs for blast resistance in japonica rice cultivars.

Prioritization of Microsatellite Markers Linked with Drought Tolerance Associated Traits in Chickpea (Cicer arietinum L.)

Background: Being a vital source of high-quality dietary protein, chickpea is an unavoidable legume. The present investigation was performed to study the applicability of the microsatellite markers linked with drought tolerance in Indian chickpea genotypes collected from different genetic background. Methods: In Rabi 2021-22, forty chickpea genotypes including national check for drought tolerance, elite cultivars, released varieties and advanced breeding lines were screened employing forty microsatellite markers linked with drought tolerance associated traits. Results: Among forty drought tolerance related microsatellite markers, twenty-six were found to be polymorphic and produced a total of 66 alleles, with a mean of 2.5 alleles per locus. Genotype NCPGR127 had highest numbers of alleles, gene diversity and polymorphism information content tracked by genotype TR19. These genotypes may be used for selecting drought tolerant genotypes through marker assistant selection (MAS). Model-based population structure analysis clearly distinguished the drought tolerant genotypes including ICC4958, JG74, JAKI9218, JG16, JG6, JG14 and JG11. Principle coordinate analysis (PCoA) and analysis of molecular variance (AMOVA) further confirmed these results. Findings of the present investigation have a greater potential for further utilization in breeding of drought specific chickpea cultivar(s).