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Argentina is the single exporter of non-gmo hard endosperm maize to the European Union, and is internationally known for its grain hardness. This special hard endosperm maize supply chain follows strict regulations to ensure a high quality grain. Specific values for test weight, flotation index, grain vitreousness, and screen retention are demanded by the dry milling industry. Central temperate Argentinean production system is currently changing to later sowings, and there is limited information on the effect of contrasting sowing dates over specific grain quality attributes of interest for the industry. In this study we explored the effects of delaying maize sowing dates from September-October to December on maize dry milling grain quality in the central temperate area. Eighteen commercial genotypes differing in grain hardness were sown during two growing seasons and two sowing dates. Measured traits were grain yield, individual grain weight, dry milling quality (test weight, floaters, vitreousness, 8 mm screen retention), and composition (oil, protein, starch). Grain yield varied significantly among genotypes (p < 0.001), and semi-dents showed higher yields when compared to hard endosperm flints (13 110 and 11 463 kg ha−1, respectively). Early and late sown maize yielded 12 737 kg ha−1 and 11 003 kg ha−1, respectively. Significant genotype differences were observed for all grain quality and composition attributes. Delaying the sowing date from September-October to December had minimum effects on physical grain quality traits, only evident at some genotypes (significant sowing date x genotype interaction for most traits). Genotype to genotype differences in grain quality and composition were larger than variations between sowing dates. Grain hardness was strongly determined by the genotype, making genotype selection a critical management option for attaining high quality at any sowing date. It is evident that high dry milling quality can be obtained with adequate genotypes also at later sowings. Fil: Abdala Alonso, Lucas Jorge. Universidad Nacional de Rosario. Facultad de Ciencias Agrarias. Cátedra de Cultivo Extensivos Cereales y Oleaginosas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnol.conicet - Rosario. Unidad de Direccion; Argentina Fil: Gambin, Brenda Laura. Universidad Nacional de Rosario. Facultad de Ciencias Agrarias. Cátedra de Cultivo Extensivos Cereales y Oleaginosas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Investigaciones en Ciencias Agrarias de Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Agrarias. Instituto de Investigaciones en Ciencias Agrarias de Rosario; Argentina Fil: Borras, Lucas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Investigaciones en Ciencias Agrarias de Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Agrarias. Instituto de Investigaciones en Ciencias Agrarias de Rosario; Argentina. Universidad Nacional de Rosario. Facultad de Ciencias Agrarias. Cátedra de Cultivo Extensivos Cereales y Oleaginosas; Argentina

The effect of various soaking mediums, viz. water (control), 3% NaCl and 0.2% acetic acid, and without soaking on the physicochemical properties of parboiled selected glutinous (TDK8 and TDK11) and non-glutinous (Doongara) was investigated in the present study. Results showed that the chemistry of soaking had a significant effect on the head rice yield (HRY), grain hardness, crystallinity, color, pasting and thermal properties, textural attributes, and glycemic index of these rice varieties. Soaking with NaCl and acetic acid significantly increased the grain hardness and HRY than control and without soaking treatments. Acetic acid and NaCl soaking significantly affected crystalline regions of starch resulting in reduced crystallinity in X-ray diffraction analysis and thermal endotherms in DSC analysis. NaCl soaking induced swelling of starch granules resulting in high peak and final viscosities. However, acetic acid restricted swelling resulting in reduced peak and final viscosities. NaCl and acetic acid soakings also resulted in increased hardness and adhesiveness of cooked grains than normal water soaked and un-soaked parboiled rice samples. Interestingly, change in textural attributes was prominent in parboiled glutinous rice. The color difference value for fresh parboiled samples was significantly lower for acetic acid soaked samples compared to NaCl soaked and un-soaked samples probably due to bleaching effect of acetic acid. Moreover, parboiling also resulted in significant reduction in glycemic index of glutinous rice. These findings revealed the potential application of parboiling with modified soaking techniques to improve the grain quality.

Викладено результати вивчення успадкування твердості зерна у зразків пшениці м’якої колекції НЦГРРУ. Встановлено характер її успадкування в F1: проміжне успадкування (54,2 %), негативне домінування (29,2 %) та позитивне домінування (16,7). Найбільша кількість гібридних популяцій F2 розщеплюється за дигібридною схемою (66,7 %), значно менша – за тригібридною (25 %), у двох – за моногенною (8,3 %)., Цель и задачи исследования. Установить закономерности наследования твердости зерна у коллекционных образцов пшеницы мягкой озимой.Обсуждение результатов.В результате анализа полученных данных установлен разный характер наследования твердости зерна в F1, а именно: промежуточное наследование, положительное доминирование и отрицательное доминирование (hp = от 1 до -1). Среди 24 гибридов первого поколения 13 имели промежуточный тип наследования, семь гибридных комбинаций имели отрицательное доминирование и в четырех комбинациях наблюдалось положительное доминирование. В зависимости от генотипов родительских форм в F2 расщепление по твердости зерна проходило в соответствии с моно-, ди- или тригибридной схемой. Формирование текстуры эндосперма осуществлялось преимущественно при аддитивной полимерии. Расщепление по твердости зерна в F2 и распределение по фенотипу происходило в зависимости от генотипа родительских форм.Выводы. Установлен характер наследования твердости зерна гибридами F1, который происходит по следующим типам: промежуточное наследование (54,2 %), отрицательное доминирование (29,2 %) и положительное доминирование (16,7) – hp = от 1 до -1. Установлен также материнский эффект влияния на формирование текстуры гибридного эндосперма зерна F1. При анализе гибридных зерен F2 было установлено, что наибольшее количество комбинаций расщепляется по дигибридной схеме 15:1, 9:7, 7:9 (66,7 %). Тригибридный тип расщепления наблюдали в шести комбинациях (25 %), моногенный – у двух (8,3 %)., The aim and tasks of the study. To establish patterns in the inheritance of grain hardness in collection bread winter wheat accessions.Results and discussion. The data demonstrate different nature of the grain hardness inheritance in F1, namely: intermediate inheritance, positive dominance and negative dominance (hp = from 1 to - 1). Of 24 F1 hybrids, 13 had intermediate inheritance, 7 hybrid combinations had negative dominance, and positive dominance was observed in 4 combinations. Depending on the parent genotypes, the grain hardness segregation in F2 was in accordance with the mono-, di- or three-hybrid scheme. Endosperm texture was mainly formed by additive polymeria. The grain hardness segregation in F2 and the phenotype distribution occurred depending on the genotypic composition of parents.Conclusions. The nature of the grain hardness inheritance in F1 hybrids was established; it occurred according to the following types: intermediate inheritance (54.2%), negative dominance (29.2%) and positive dominance (16.7): hp = 1 − -1. The female effect was also established for the endosperm texture formation in F1 hybrid grain. Analyzing F2 hybrid grain, we noticed the greatest number of combinations segregated by dihybrid scheme: 15: 1, 9: 7, 7: 9 (66.7%). Three-hybrid type of segregation was observed in 6 combinations (25%); monogenic - in 2 (8.3%)

To study drought stress effect on grain quality properties of wheat, an experiment was conductedusing 169 recombinant inbreed lines (RILS) under water stress and non-stress condition and with two separated lattice designs. Grain yield, protein yield, protein content, volume of Zeleny sediment, grain hardness, water absorption, grain moisture content and grain dry matter were evaluated. Analysis of variance showed that there were significant differences among the lines for all traits. Moreover, comparison between two lines in two environmental conditions showed, the quality in bread wheat under drought stress conditions due to increment of protein yield is improved. Protein yield in both irrigation regimes has a significant and negative correlation with grain moisture and in the other hand, significant and positive correlation with the grain hardiness dry matter, Zeleny sedimentation and water intake in both conditions. The results showed that the identification of favorable quality characteristics in optimum and stressed conditions were possible and the lines with high grain quality can be used in breeding programs for improving of baking quality. Although some drought sensitive genotypes possessed a favorable baking quality but their grain yield was low.

Gene silencing by RNA interference (RNAi) is a particularly important tool in the study of gene function in polyploid cereal species for which the collections of natural or induced mutants are very limited. Previously we have been testing small interfering RNA (siRNA)-based approach of gene silencing in wheat and triticale. In this research artificial microRNAs (amiRs) were studied in the same species and the same target genes to compare effectiveness of both gene silencing pathways. amiR cassettes were designed to silence Puroindoline a (Pina) and Puroindoline b (Pinb) hardness genes in wheat and their orthologues Secaloindoline a (Sina) and Secaloindoline b (Sinb) genes in triticale. Each of the two cassettes contained 21 nt microRNA (miR) precursor derived from conserved regions of Pina/Sina or Pinb/Sinb genes respectively. Transgenic plants were obtained with high efficiency in two cultivars of wheat and one cultivar of triticale after using the Pinb-derived amiR vector for silencing of Pinb or Sinb respectively. Lack of transgenic plants in wheat or very low transformation efficiency in triticale was observed using the Pina-derived amiR cassette, despite large numbers of embryos attempted. Silencing of Pinb in wheat and Sinb in triticale was highly efficient in the T1 generation. The transcript level of Pinb in wheat was reduced up to 92% and Sinb in triticale was reduced up to 98%. Moreover, intended silencing of Pinb/Sinb with Pinb-derived amiR cassette was highly correlated with simultaneous silencing of Pina/Sina in the same transgenic plants. High downregulation of Pinb/Pina genes in T1 plants of wheat and Sinb/Sina genes in T1 plants of triticale was associated with strong expression of Pinb-derived amiR. Silencing of the target genes correlated with increased grain hardness in both species. Total protein content in the grains of transgenic wheat was significantly lower. Although, the Pinb-derived amiR cassette was stably inherited in the T2 generation of wheat and triticale the silencing effect including strongly decreased expression of silenced genes as well as strong expression of Pinb-derived amiR was not transmitted. Advantages and disadvantages of posttranscriptional silencing of target genes by means of amiR and siRNA-based approaches in polyploid cereals are discussed.

This work was aimed at defining models to explain tensile properties of thermoplastic films derived from common wheat flours as a function of source flours characteristics. A total of 26 flours, two blends from an industrial mill and 24 single-cultivar flours collected over three different years of grain production (from 2013 to 2015) and cultivar grain hardness (from soft to hard) were used in a wide range of protein content (from 9.0 to 16.2%) and values of Chopin's alveograph parameters (as indexes of gluten characteristics), i.e., P (from 27 to 160 mm), L (from 32 to 236 mm), P / L (from 0.13 to 4.44), and W (from 63 to 398). The same plasticization recipe and filming procedure was adopted for all manufactures. The maximum tensile strength ( σ max ) and the elongation at break ( e max ), as well as the elastic modulus ( E ), stiffness ( k ) and energy at break ( w b ) of films from flours having moderate to high values of P (>60 mm), P / L (≥0.43) and W (>170) were positively correlated to P and negatively correlated to P / L and W , with all the variables significant ( p -value R 2 = 0.72 for σ max , 0.62 for e max , 0.81 for E , 0.83 for k and 0.72 for w b . The e max of films obtained from flours having moderate to low values of P (≤45 mm), P / L (≤0.42) and W (≤160) was negatively correlated to P , L and P / L , and positively correlated with W , with all the variables significant ( p -value R 2 = 0.86. On the contrary, no relationship was found for the σ max , as well as for E , k and w b of these films. Results encourage further research aimed at improving the robustness and reliability of models so that tensile properties of a thermoplastic film can be predicted for any given source flour.

Maize (Zea mays L.) cultivars with dent grains present higher starch and dry matter ruminal degradability than those with flint grains. This study aimed to assess genetic parameters of degradability in maize grains of different textures and to verify whether there is an association between grain indentation score and ruminal dry matter (RDM) degradability. The evaluated progenies were obtained from the cross between the varieties Cristal (flint) and Cunha (dent), previously selected for grain hardness. Progenies were evaluated for an indentation score using a visual grading scale ranging from 1 (flint) to 5 (dent). To assess the RDM degradability, 5 g were cut into halves, weighed (five grams), stored in bags made of 100% "failet" cloth and incubated for 24 h in the rumen of three ruminally cannulated cows. There was genetic variability for RDM degradability and heritability was 46%, indicating the possibility of success using a selection. There was no association between indentation score and RDM degradability percentage; thus, visual evaluation not always reflects grain hardness per se since it indicates the pericarp aspect but not the endosperm constitution.

The production of bioplastics directly from wheat flour has been demonstrated to be reliable, but scarce knowledge is available on how flour characteristics may affect the performance of thermoplastic films. In this work, we first established the most suitable recipe and process for the production of extruded films and then we used eight single-cultivar wheat flours with different baking technological properties to assess how they affect the mechanical properties of thermoplastic films. The results have shown that flours from soft grain cultivars offered more rigid and deformable films than flours from hard grain cultivars. For similar hardness, the alveographic P/L ratio of the dough was inversely related to rigidity and directly related to deformability of plastic films, while the deformation energy of the dough (W) played a role only for great differences of it. The subsequent fabrication of blends between each of the flours that yielded the best film properties and polycaprolactone (PCL) at different proportions indicated that a wheat flour/PCL ratio (TWF/PCL) of 75/25 offered the most suitable films for further application. Our results are likely to be useful for improving the plasticization of flour, in that selection of wheat flours could be tailored on the properties desired for the bioplastic films.

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.

A disponibilização anual de genótipos de milho é grande, sendo necessária uma adequada avaliação desses genótipos para serem indicados para a produção de silagem. Objetivou-se avaliar as características bromatológicas da silagem produzida a partir de diferentes genótipos de milho, bem como, avaliar se a base genética ou a dureza dos grãos podem alterar a indicação de genótipos de milho para silagem. O experimento foi realizado na área experimental da Universidade Tecnológica Federal do Paraná, no delineamento blocos completos ao acaso, avaliando-se os 30 genótipos do ensaio Sul Super Precoce, organizado pela Embrapa. Avaliaram-se as características bromatológicas da silagem produzida com os diferentes genótipos, posteriormente eles foram agrupados segundo a base genética e a textura dos grãos. Verificou-se que os genótipos do ensaio Sul Super Precoce não podem ser diferenciados segundo a base genética ou a textura dos grãos para todas as características avaliadas. Porém, eles podem ser diferenciados pela matéria seca da silagem. The annual availability of corn genotype is very large, requiring a proper assessment to be indicated for the production of silage. The aim of this study was to evaluate the chemical characteristics of corn genotypes for silage production, and assess whether the grain genetic basis or hardness may change the indication of corn cultivars for silage. The experiment was conducted at the experimental area of the Universidade Tecnológica Federal of Paraná, in the randomized block design, evaluating 30 genotypes of experiment Super Early South. It was evaluated the chemical characteristics of the genotypes and, after they were grouped according to the characteristics of genetic basis and of grain texture. It was found that the genotypes of the experiment South Super Early cannot be differentiated according to the genetic basis of grain and texture for all traits. However, they can be distinguished by the dry matter silage.

Wheat (Triticum aestivum L.) is one of the most successful domesticated plant species in the world. The majority of wheat carries mutations in the Puroindoline genes that result in a hard kernel phenotype. An evolutionary explanation, or selective advantage, for the spread and persistence of these hard kernel mutations has yet to be established. Here, we demonstrate that the house mouse (Mus musculus L.) exerts a pronounced feeding preference for soft over hard kernels. When allele frequencies ranged from 0.5 to 0.009, mouse predation increased the hard allele frequency as much as 10-fold. Studies involving a single hard kernel mixed with ~1000 soft kernels failed to recover the mutant kernel. Nevertheless, the study clearly demonstrates that the house mouse could have played a role in the evolution of wheat, and therefore the cultural trajectory of humankind.

Wheat kernel texture, a major trait determining the end-use quality of wheat flour, is mainly influenced by puroindolines. These small basic proteins display in vitro lipid binding and antimicrobial properties, but their cellular functions during grain development remain unknown. To gain an insight into their biological function, a comparative proteome analysis of two near-isogenic lines (NILs) of bread wheat Triticum aestivum L. cv. Falcon differing in the presence or absence of the puroindoline-a gene (Pina) and kernel hardness, was performed. Proteomes of the two NILs were compared at four developmental stages of the grain for the metabolic albumin/globulin fraction and the Triton-extracted amphiphilic fraction. Proteome variations showed that, during grain development, folding proteins and stress-related proteins were more abundant in the hard line compared with the soft one. These results, taken together with ultrastructural observations showing that the formation of the protein matrix occurred earlier in the hard line, suggested that a stress response, possibly the unfolded protein response, is induced earlier in the hard NIL than in the soft one leading to earlier endosperm cell death. Quantification of the albumin/globulin fraction and amphiphilic proteins at each developmental stage strengthened this hypothesis as a plateau was revealed from the 500 degrees Cd stage in the hard NIL whereas synthesis continued in the soft one. These results open new avenues concerning the function of puroindolines which could be involved in the storage protein folding machinery, consequently affecting the development of wheat endosperm and the formation of the protein matrix.

Maize (Zea mays L.) cultivars with dent grains present higher starch and dry matter ruminal degradability than those with flint grains. This study aimed to assess genetic parameters of degradability in maize grains of different textures and to verify whether there is an association between grain indentation score and ruminal dry matter (RDM) degradability. The evaluated progenies were obtained from the cross between the varieties Cristal (flint) and Cunha (dent), previously selected for grain hardness. Progenies were evaluated for an indentation score using a visual grading scale ranging from 1 (flint) to 5 (dent). To assess the RDM degradability, 5 g were cut into halves, weighed (five grams), stored in bags made of 100% "failet" cloth and incubated for 24 h in the rumen of three ruminally cannulated cows. There was genetic variability for RDM degradability and heritability was 46%, indicating the possibility of success using a selection. There was no association between indentation score and RDM degradability percentage; thus, visual evaluation not always reflects grain hardness per se since it indicates the pericarp aspect but not the endosperm constitution. Cultivares de milho (Zea mays L.) com grãos do tipo dentado possuem maior porcentagem de amido e degradabilidade ruminal da matéria seca do que os com grãos do tipo duro. Estimaram-se parâmetros genéticos da degradabilidade de grãos de milho com diferentes texturas e verificou-se se ocorre associação entre o escore de identação dos grãos visualmente avaliados e a degradabilidade in situ da matéria seca (DISMS). Foram avaliadas progênies oriundas do cruzamento entre a variedade Cristal, de grãos duros, e a variedade Cunha de grãos dentados, previamente selecionadas para a dureza dos grãos. As progênies foram avaliadas com relação ao escore de identação por meio de uma escala visual de notas variando de 1 (duro) a 5 (mole). Para a avaliação da DISMS os grãos foram cortados ao meio, pesados 5 g colocados em saquinhos de tecido "failet" e incubados no rúmen, por 24 h, em três vacas portadoras de cânula ruminal. Há variabilidade genética para a DISMS, com herdabilidade de 46%, indicando ser possível o sucesso com a seleção. Não há associação entre o escore de identação e a porcentagem de DISMS. Assim, a avaliação visual nem sempre reflete a dureza per se dos grãos, pois o que se vê é o aspecto do pericarpo e não a constituição do endosperma.

Wheat endosperm texture is correlated with one major locus, Ha, located on the short arm of chromosome 5D, which comprises several genes among which are two puroindoline genes, Pina and Pinb. In this study, we used two near-isogenic lines, the hard-textured line lacking Pina and the soft-textured line containing both Pina and Pinb wild-type genes. Hard and soft endosperms were observed at four kernel developmental stages, from 180 degrees Cd to 750 degrees Cd. Puroindolines were located within protein bodies at the onset of prolamin accumulation by transmission electron microscopy and immunolabelling. Ab initio modeling showed a closer structural relationship between puroindolines and 2S storage proteins from dicots than between puroindolines and other cysteine-rich wheat proteins, i.e. LTP and amylase inhibitors. Compared to the soft line, storage protein polymers in the hard line exhibited higher molecular mass (increase of from 6 to 93%) and polydispersity indices (increase of from 26 to 63%) over the course of the 4-year experiment. This suggests that puroindolines might impact the aggregation of storage proteins. Finally, these data pave the way for investigation of the role of protein-protein interactions in the texture of wheat endosperm. (C) 2011 Elsevier Ltd. All rights reserved.

Flour and dough quality are very important breeding traits for wheat (Triticum aestivum L) the selection of which would benefit from linked molecular markers. Association analysis allows the identification of genes or quantitative trait loci (QTL) related to target traits. The effectiveness of this approach depends on the availability of a densely genotyped population with large genetic variability for the traits of interest. Our objective was to identify chromosomal regions associated with flour and dough quality traits using a core collection built by maximizing the genetic diversity and phenotypic variability. We investigated the association of DArT, SSR and SNP markers with grain protein content, grain hardness, water-extractable arabinoxylan (WEAX) viscosity, wholemeal flour color and dough rheology. Out of 803 markers tested, 130 markers spread over the genome were associated with at least one trait, varying from 20 associated with WEAX viscosity to 60 associated with dough quality. Most chromosome regions known to determine wheat quality from the study of several bi-parental recombinant inbred lines were confirmed here and some new regions were identified. Associations were found for each trait studied, demonstrating that the core collection is a useful tool for QTL association mapping of these and other traits of interest. (C) 2011 Elsevier Ltd. All rights reserved.

Whereas gluten fraction accounts for 30-60% of the variation in wheat bread-making quality, there remains substantial variation determined by non-gluten factors. The objective of this study was to detect new loci for wheat quality. The genetics of sodium dodecyl sulphate-sedimentation volume (Ssd), grain hardness (GH), grain protein content, wet gluten content (WGC) and water absorption (Abs) in a set of 198 recombinant inbred lines derived from two commercial varieties was studied by quantitative trait loci (QTL) analysis. A genetic map based on 255 marker loci, consisting of 250 simple sequence repeat markers and five glutenin loci, Glu-A1, Glu-B1, Glu-D1, Glu-B3 and Glu-D3, was constructed. A total of 73 QTLs were detected for all traits. A major QTL for GH was detected on chromosome 1B and its relative contribution to phenotypic variation was 27.7%. A major QTL for Abs on chromosome 5D explained more than 30% of the phenotypic variation. Variations in Ssd were explained by four kinds of genes. Some QTLs for correlated traits mapped to the same regions forming QTL clusters or indicated pleiotropic effects.

International audience; Amphiphilic proteomic analysis was carried out on the ITMI (International Triticae Mapping Population) population resulting from a cross between 'Synthetic', i.e.: 'W7984' and 'Opata'. Out of a total of 446 spots, 170 were specific to either of the two parents, and 276 were common to both. Preliminary analysis, which was performed on 80 progenies (Amiour et al. 2002a), was completed here using a total of 101 selfed lines. Seventy two Loci of amphiphilic spots placed at LOD = 5 were conclusively assigned to15 chromosomes. Some spots mapped during the first analysis were eliminated because of the significant distortion segregation observed in the second analysis. Group-1 chromosomes had by far the greatest number of mapped spots (51). Using the Quantitative Trait Loci (QTLs) approach, analysis of the quantitative variation of each spot revealed that 96 spots out of the 170 specific ones showed at least one Protein Quantity Locus (PQL). These PQLs were distributed throughout the genome. With Matrix Laser Desorption Ionisation Time Of Flight (MALDI-TOF) spectrometry and Database interrogation, a total of 93 specific and 41 common spots were identified. This enabled us to show that the majority of these proteins are associated with membranes and/or play a role in plant defence against external invasions. Using multiple-regression analysis, other amphiphilic proteins, in addition to puroindolines, were shown to be involved in variation in kernel hardness in the ITMI population.

Factors responsible for grain hardness in sorghum are not well understood. Therefore, a study was undertaken to observe differences in the developmental processes of three sorghum varieties which vary in endosperm texture: hard, intermediate, and soft. Grain samples were collected at 5 day intervals beginning at 5 days after half-bloom (DAHB) until physiological maturity (40 DAHB) and prepared for viewing with scanning electron microscopy and transmission electron microscopy. Comparisons were made between vitreous and floury endosperm portions of each variety and among the three varieties. The major difference between vitreous and floury endosperm was the degree to which the protein matrix was present and continuous. The protein matrix which surrounds the starch granules forms at approximately 20 DAHB. The proportion of cells in the endosperm with a continuous protein matrix corresponds to the proportion of vitreous endosperm in the mature kernel. A similar sequence of development was observed in the hard, intermediate, and soft varieties. however, the harder varieties appeared to develop faster than the softer varieties. Differences between hard and soft varieties were visible as early as 15 DAHB. In the early stages of endosperm development, the hard variety had a higher concentration of protein bodies in the outer endosperm than the softer varieties.