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Purpose: Kernel texture plays a principal role in determining technological flour properties and end-use quality of wheat products. Hence, a multi-year mutation induction programme was conducted to isolate advanced wheat mutant lines with agro-morphologically superior performance, higher disease resistance and harder grain texture., Materials and Methods: Radiation mutagenesis was employed in soft textured wheat variety HPW 89 using gamma rays dose of 250, 300 and 350 Gy (Co 60 : BARC, Mumbai) and evaluated across M 1-5 generations. Promising superior mutants selected were evaluated during M 4 and M 5 generation for induced variability and trait association for agro-morphological and quality traits. The screened mutants were also determined for induced changes at genetic level using gene specific markers for puroindoline genes., Results: A total of 293 agro-morphologically superior mutants isolated showed significant genetic variation in the M 4 generation. Single kernel characterization system categorized 267 mutants (8.79-50.06) with higher grain hardness than the HPW 89 variety (7.39). Among these, 108 mutants were selected for agro-morphological and molecular characterization. Significant variations were found in these mutants in either pina and pinb or both puroindoline genes. Clustering among these mutants led to the formation of five clusters and a total of eleven mutants were found with better set of agro-morphological, disease resistance and quality traits., Conclusion: These mutants can serve as important genetic resource for developing harder texture bread wheat varieties in the future grain quality improvement programmes. These mutants will also bridge the need of bakers and millers' requirement of varieties with specific texture and quality.

Grain hardness has important effects on grain quality and the end-use of wheat. In this study, a collection of 103 common wheat germplasms and a DH population of 194 lines were used to identify new quantitative trait loci (QTL) for grain hardness. Two stable genetic loci on chromosome 5D were detected under different locations and years with one of them being the Ha locus on 5DS where the major gene Puroindolines for wheat grain hardness is located. Another locus of qTaHa-5DL also showed a significant impact on grain hardness index (HI) with HI increasing from ~ 20 to ~ 45 and hardness type changing from soft to mixed when Puroindolines are wild type. A kompetitive allele-specific PCR (KASP) marker for qTaHa-5DL was developed and the effectiveness of the QTL was confirmed in 184 breeding lines with the marker K-Ha5DL dividing wheat into two distinct categories. This new QTL can be effectively used to select soft or medium hard wheat., (© 2024. The Author(s).)

Purpose: Sustainable wheat production and higher genetic gains can be realized by broadening the genetic base and improving the well adapted varieties. In the present study, a multi-year experiment involving induced mutagenesis was conducted to create genetic variation, assess trait associations and genetic divergence in four wheat varieties with differential grain texture treated with six doses of gamma rays and ethyl methane sulfonate using ten agro-morphological traits., Materials and Methods: Healthy selfed seeds of four bread wheat varieties with differential texture were irradiated using six doses ranging from 175 Gy-300 Gy of gamma rays (Co 60 : BARC, Mumbai) and six concentrations of ethyl methanesulfonate (0.3-1.3%) (Sigma-Aldrich, Bangalore, India) to evaluate variability, character association and degree of genetic diversity induced among the mutagenic treatments of wheat varieties with differential grain texture., Results: Significant inter-population differences were observed for almost all the traits. The sample mean of twelve mutant populations in each of the cultivar exhibited superior quantitative phenotypic traits and increased values of the genetic parameters. Based on association and variability studies, plant height, spike length, grain filling period, biological yield per plant and harvest index can be used as early generation criteria for maximum genetic improvement. Multivariate studies indicated the contribution of various traits towards divergence and indicated the efficiency of mutagens in generating variability. Gamma-irradiation dosages between 200-250 Gy and 0.5-1.1% EMS for soft-textured varieties, whereas doses between 225-275 Gy and 0.5-0.9% EMS were found to be most potent for semi-hard-textured varieties., Conclusions: Assessment of mutagen sensitivity showed that semi-hard wheat varieties were responsive to both mutagens, particularly EMS and generated higher variability and divergence than the soft textured varieties. Hence, gamma rays were proved to be more effective in generating higher variability than ethyl methanesulfonate. A total of 117 putative mutants were identified with desirable agro-morphological attributes. Among these, mutants with higher inter-cluster distance can be used as parents in hybridization programs and serve as important genetic resources in future wheat improvement programs.

Background: Gamma-irradiated mutants of Triticum aestivum L., hexaploid wheat, provide novel and agriculturally important traits and are used as breeding materials. However, the identification of causative genomic regions of mutant phenotypes is challenging because of the large and complicated genome of hexaploid wheat. Recently, the combined use of high-quality reference genome sequences of common wheat and cost-effective resequencing technologies has made it possible to evaluate genome-wide polymorphisms, even in complex genomes., Results: To investigate whether the genome sequencing approach can effectively detect structural variations, such as deletions, frequently caused by gamma irradiation, we selected a grain-hardness mutant from the gamma-irradiated population of Japanese elite wheat cultivar "Kitahonami." The Hardness (Ha) locus, including the puroindoline protein-encoding genes Pina-D1 and Pinb-D1 on the short arm of chromosome 5D, primarily regulates the grain hardness variation in common wheat. We performed short-read genome sequencing of wild-type and grain-hardness mutant plants, and subsequently aligned their short reads to the reference genome of the wheat cultivar "Chinese Spring." Genome-wide comparisons of depth-of-coverage between wild-type and mutant strains detected ~ 130 Mbp deletion on the short arm of chromosome 5D in the mutant genome. Molecular markers for this deletion were applied to the progeny populations generated by a cross between the wild-type and the mutant. A large deletion in the region including the Ha locus was associated with the mutant phenotype, indicating that the genome sequencing is a powerful and efficient approach for detecting a deletion marker of a gamma-irradiated mutant phenotype. In addition, we investigated a pre-harvest sprouting tolerance mutant and identified a 67.8 Mbp deletion on chromosome 3B where Viviparous-B1 and GRAS family transcription factors are located. Co-dominant markers designed to detect the deletion-polymorphism confirmed the association with low germination rate, leading to pre-harvest sprouting tolerance., Conclusions: Short read-based genome sequencing of gamma-irradiated mutants facilitates the identification of large deletions linked to mutant phenotypes when combined with segregation analyses in progeny populations. This method allows effective application of mutants with agriculturally important traits in breeding using marker-assisted selection., (© 2022. The Author(s).)

The physicochemical and functional characteristics of grain, meal and flour of timely sown wheat (TSW) and delayed sown wheat (DSW) were compared to see the effects of heat stress (HS). TSW and DSW of different lines were sown as per the approved timings. DSW experienced higher temperature during flowering and had shorter vegetative and maturation period than TSW. Pasting and dough rheological properties were measured using Rapid Visco-Analyser and Farinograph, respectively, while gliadins and glutenins profiling was done by SDS-PAGE. Delayed sowing decreased grain yield and diameter while increased protein and all categories of gliadins and high molecular weight glutenins. DSW showed higher peak viscosity, breakdown-viscosity and dough stability and lower setback viscosity, damaged starch, arabinoxylans and water absorption than TSW. HS in DSW appeared to lower starch synthesis causing proportionate increase in grain hardness and proteins content leading to changes in milling and rheological characteristics., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Background: Durum wheat is considered not suitable for making many food products that bread wheat can. This limitation is largely due to: (i) lack of grain-hardness controlling genes (Puroindoline a and b) and consequently extremely-hard kernel; (ii) lack of high- and low-molecular-weight glutenin subunit loci (Glu-D1 and Glu-D3) that contribute to gluten strength. To improve food processing quality of durum wheat, we stacked transgenic Pina and HMW-glutenin subunit 1Ax1 in durum wheat and developed lines with medium-hard kernel texture., Results: Here, we demonstrated that co-expression of Pina + 1Ax1 in durum wheat did not affect the milling performance that was enhanced by Pina expression. While stacking of Pina + 1Ax1 led to increased flour yield, finer flour particles and decreased starch damage compared to the control lines. Interestingly, Pina and 1Ax1 co-expression showed synergistic effects on the pasting attribute peak viscosity. Moreover, Pina and 1Ax1 co-expression suggests that PINA impacts gluten aggregation via interaction with gluten protein matrix., Conclusions: The results herein may fill the gap of grain hardness between extremely-hard durum wheat and the soft kernel durum wheat, the latter of which has been developed recently. Our results may also serve as a proof of concept that stacking Puroindolines and other genes contributing to wheat end-use quality from the A and/or D genomes could improve the above-mentioned bottleneck traits of durum wheat and help to expand its culinary uses.

Our previous genetic analysis of a tetraploid wild wheat species, Aegilops peregrina, predicted that a single gene per haploid genome, Bgc-1, controls B-type starch granule content in the grain. To test whether bread wheat (Triticum aestivum L.) has orthologous Bgc-1 loci, we screened a population of γ-irradiated bread wheat cv. Paragon for deletions of the group 4 chromosomes spanning Bgc-1. Suitable deletions, each encompassing ~600-700 genes, were discovered for chromosomes 4A and 4D. These two deletions are predicted to have 240 homoeologous genes in common. In contrast to single deletion mutant plants, double deletion mutants were found to lack B-type starch granules. The B-less grains had normal A-type starch granule morphology, normal overall starch content, and normal grain weight. In addition to variation in starch granule size distribution, the B-less wheat grains differed from controls in grain hardness, starch swelling power, and amylose content. We believe that these B-less wheat plants are the only Triticeae cereals available that combine substantial alterations in starch granule size distribution with minimal impact on starch content., (© The Author 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology.)

Kernel hardness determined by two tightly linked Puroindoline genes, Pina-D1 and Pinb-D1, located on chromosome 5DS define commercially important characteristics, uses, major grades and export markets of wheat. This study was conducted to characterize Pina-D1 and Pinb-D1 alleles, in fifteen synthetic hexaploid wheats (SHWs) and its relation with grain hardness. Additionally, in silico functional analyses of puroindoline-a protein was conducted for better understanding of their putative importance in grain quality. Six different Pina-D1 alleles were identified in the SHWs, of which three i.e. Pina-D1a, Pina-D1c and Pina-D1d were already known whereas the other three had new sequence polymorphisms and were designated as Pina-D1w, Pina-D1x and Pina-D1y. Three different Pinb-D1 alleles were identified which have been reported earlier and no novel sequence polymorphism was detected. It was concluded that despite some primary, secondary and 3D structure variations, ligand binding sites and disulfide bonds discrepancies, the main features of PINA, i.e. the tryptophan-rich domain, the cysteine backbone, the signal peptide and basic identity of the proteins were all conserved. In silico analysis showed that puroindolines having binding capacity with small parts of prolamins causing celiac disease of human, however their potential role is not obvious. Conclusively, the new Pina-D1 alleles with modest effect on grain hardness, and insight into their functional and structural characteristics are important findings and their putative role in celiac disease require further studies to validate., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Endosperm texture, i.e. the hardness or softness of the grain, is an important quality criterion in cereals because it determines many grain end-use properties. Grain softness is the dominant trait and is mainly controlled by the Ha locus on the short arm of chromosome 5D in hexaploid bread wheat. Genes for puroindoline a (Pina-D1), puroindoline b (Pinb-D1), and grain softness related protein (Gsp-D1) have been shown to be linked to the Ha locus in different mapping populations and have been associated with the expression of grain softness. The study of the linkage relationships among these genes has been limited by the low level of polymorphism in the D genome of hexaploid Triticum aestivum. In the present study, a highly polymorphic Triticum monococcum mapping population was used to analyze linkage relationships among these three genes. Gsp-Am1 and Pina-Am1 were found to be completely linked and lie 0.14 cM distal to Pinb-Am1 in the distal region of the short arm of chromosome 5Am. The tight genetic linkage among these three genes was paralleled by their physical proximity within a single 105-kb clone isolated from a T. monococcum bacterial artificial chromosome (BAC) library. A restriction map of this BAC clone showed that Pina-Am1 is located between Pinb-Am1 and Gsp-Am1. Partial sequences of the T. monococcum genes showed a high degree of similarity with their T. aestivum counterparts (> or =94%). Marker-assisted selection strategies based on the tight linkage among Ha-related genes are discussed.

Wheat (Triticum aestivum L.) grain hardness is determined mainly by variations in puroindoline genes (Pina-D1 and Pinb-D1), which are located on the short arm of chromosome 5D. This trait has a direct effect on the technological properties of the flour and the final product quality. The objective of the study was to analyze the mutation frequency in both Pin genes and their influence on grain hardness in 118 modern bread wheat cultivars and breeding lines cultivated in Poland, and 80 landraces from Poland. The PCR products containing the Pin gene coding sequences were sequenced by the Sanger method. Based on detected the SNPs (single-nucleotide polymorphisms) we designed CAPS (cleaved amplified polymorphic sequence) markers for the fast screening of Pinb alleles in a large number of genotypes. All analyzed cultivars, breeding lines, and landraces possess the wild-type Pina-D1a allele. Allelic variation was observed within the Pinb gene. The most frequently occurring allele in modern wheat cultivars and breeding lines (over 50%) was Pinb-D1b. The contribution of the remaining alleles (Pinb-D1a, Pinb-D1c, and Pinb-D1d) was much less (approx. 15% each). In landraces, the most frequent allele was Pinb-D1a (over 70%), followed by Pinb-D1b (21% frequency). Pinb-D1c and Pinb-D1g were found in individual varieties. SKCS (single-kernel characterization system) analysis revealed that grain hardness was strictly connected with Pinb gene allelic variation in most tested cultivars. The mean grain hardness values were significantly greater in cultivars with mutant Pinb variants as compared to those with the wild-type Pinb-D1a allele. Based on grain hardness measured by SKCS, we classified the analyzed cultivars and lines into different classes according to a previously proposed classification system.

Abstract: Grain hardness defines the primary commercially important characteristics of wheat, its major grades, its uses and export markets. The puroindoline genes Pina-D1 and Pinb-D1, located only on chromosome 5D of common wheat and encoding small lipid-binding proteins, the puroindolines, are considered to be key genes that determine grain texture, the ‘soft’ texture being wild-type and hard texture being determined by either Pina-D1 gene deletion or a number of separate point mutations in Pinb-D1a, a small number of these being reported to offer different grades of hardness. We have analysed the Pina-D1 and Pinb-D1 genes of 55 Australian hard wheat cultivars, by amplification of the genes, identification of any null mutants, determination of variations in Cleaved Amplified Polymorphic Sequences (CAPS) due to certain point mutations in Pinb-D1, and/or DNA sequencing. The results show that 17 of the hard wheats were Pina-D1b null mutants, 33 others had the well-reported Pinb-D1b glycine-to-serine mutation and 5 were mixed seeds, but none had any other point mutations in Pinb-D1b. The results show that the Australian gene pool is limited in the range of genetically determined grades of hardness to only the two major types. In contrast, of the 30 overseas wheat land-races investigated, 3 exhibited 3 other point mutations in the Pinb-D1 that are suggested to provide different degrees of hardness. Such new genetic resources need to be utilised for the Australian breeding programs to create a range of grain textures suitable for different properties and uses of end-products. [Copyright &y& Elsevier]

Wheat (Triticum aestivum L.) grain hardness is determined mainly by variations in puroindoline genes (Pina-D1 and Pinb-D1), which are located on the short arm of chromosome 5D. This trait has a direct effect on the technological properties of the flour and the final product quality. The objective of the study was to analyze the mutation frequency in both Pin genes and their influence on grain hardness in 118 modern bread wheat cultivars and breeding lines cultivated in Poland, and 80 landraces from Poland. The PCR products containing the Pin gene coding sequences were sequenced by the Sanger method. Based on detected the SNPs (single-nucleotide polymorphisms) we designed CAPS (cleaved amplified polymorphic sequence) markers for the fast screening of Pinb alleles in a large number of genotypes. All analyzed cultivars, breeding lines, and landraces possess the wild-type Pina-D1a allele. Allelic variation was observed within the Pinb gene. The most frequently occurring allele in modern wheat cultivars and breeding lines (over 50%) was Pinb-D1b. The contribution of the remaining alleles (Pinb-D1a, Pinb-D1c, and Pinb-D1d) was much less (approx. 15% each). In landraces, the most frequent allele was Pinb-D1a (over 70%), followed by Pinb-D1b (21% frequency). Pinb-D1c and Pinb-D1g were found in individual varieties. SKCS (single-kernel characterization system) analysis revealed that grain hardness was strictly connected with Pinb gene allelic variation in most tested cultivars. The mean grain hardness values were significantly greater in cultivars with mutant Pinb variants as compared to those with the wild-type Pinb-D1a allele. Based on grain hardness measured by SKCS, we classified the analyzed cultivars and lines into different classes according to a previously proposed classification system. [ABSTRACT FROM AUTHOR]