Fertilizer Effects on Endosperm Physicochemical Properties and Resistance to Larger Grain Borer, Prostephanus truncatus (Coleoptera: Bostrichidae), in Malawian Local Maize (Zea mays L.) Varieties: Potential for Utilization of Ca and Mg Nutrition

Maize grain hardness influences storage pest resistance, a key characteristic valued by smallholder farmers. The structural changes in the endosperm determine grain hardness and are influenced by agronomic practices. The purpose of this study was to establish whether supply of calcium and magnesium based fertilizers can alter physicochemical properties of local and hybrid maize varieties and reduce the infestation by larger grain borer (Prostephanus truncatus (Coleoptera: Bostrichidae)) during storage. Two local and one hybrid maize varieties commonly grown by smallholder farmers in Malawi were cultivated under three fertilizer treatments (NPK (nitrogen, phosphorous, potassium), NPK plus gypsum, and NPK plus dolomite). After harvest, the grains were classified into flint and dent types, followed by P. truncatus infestation and determination of their physicochemical properties. The addition of gypsum and dolomite fertilizers led to higher levels of amylose, total zein and β-14 zein, traits associated with kernel hardness, compared to the application of NPK fertilizer. Moreover, local maize varieties showed higher resistance to P. truncatus infestation, hardness and biochemical properties associated with hardness (total zein, α-19 and β-14 zein, starch lysophosphatidylcholine, and non-starch free fatty acid) compared to hybrid variety. Our study suggests the potential for utilizing Ca and Mg nutrition in maize to improve kernel hardness, thus adoption of gypsum and dolomite by smallholder farmers may be beneficial against P. truncatus during storage.

Relative resistance of maize varieties against maize weevil, Sitophilus zeamais (Motschulsky), (Coleoptera: Curcolionidae)

The maize weevil, Sitophilus zeamais (Motschulsky) (Coleoptera: Curculionidae), is one of the most damaging pests of stored cereals causing severe damage to stored grains. In current investigation, six open pollinated maize varieties viz. JALAL (white), AZAM (white), SADAF (yellow), ZARD LOCAL (yellow), KASHMIRI (yellow) and PAHARI (white) were screened out in the laboratory of Entomology Department, Faculty of Agriculture, Gomal University, Dera Ismail Khan, Pakistan for their relative susceptibility/resistance to maize weevil. The experiment was laid out following completely randomized design (CRD) with 5 replicates. Results revealed that minimum (23.8) days to adult emergence of maize weevil were recorded when it was reared on variety Azam; whereas; maximum (34.2) days were recorded on variety Sadaf. Total number of F1 adults emerged were maximum (91) in Azam while minimum (62) in variety Sadaf. Percent infestation of maize kernels was maximum (39.01%) in Azam while minimum (25.80%) was recorded in variety Sadaf. Percent weight loss was maximum in Azam i.e. 26.12% while minimum percent weight loss (16.88%) was recorded in Sadaf. Maximum longevity (68.4 days) of adult weevils was recorded on Azam while minimum (53.4 days) was recorded on variety Sadaf. All the tested varieties had no significant effect on the sex ratio of emerged weevils. High germination percentage was recorded in Sadaf (90%) whereas; low germination was found in Azam (57%). The grain hardness test indicated that yellow varieties including Sadaf, Zard local and Kashmiri had maximum hardness having 317, 302.33 and 296 N grain hardness, whereas; white varieties i.e. Pahari, Jalal and Azam had minimum values of grain hardness i.e. 264.33, 251.66 and 238.33 Newton. The present work has shown that Azam is the most susceptible variety and should not be stored for longer periods whereas; Sadaf is the resistant variety against maize weevil.

RNAi suppression of xylan synthase genes in wheat starchy endosperm

The xylan backbone of arabinoxylan (AX), the major cell wall polysaccharide in the wheat starchy endosperm, is synthesised by xylan synthase which is a complex of three subunits encoded by the GT43_1, GT43_2 and GT47_2 genes. RNAi knock-down of either GT43_1 or all three genes (triple lines) resulted in decreased AX measured by digestion with endoxylanase (to 33 and 34.9% of the controls) and by monosaccharide analysis (to 45.9% and 47.4% of the controls) with greater effects on the amount of water-extractable AX (to 20.6 and 19.9% of the controls). Both sets of RNAi lines also had greater decreases in the amounts of substituted oligosaccharides released by digestion of AX with endoxylanase than in fragments derived only from the xylan backbone. Although the GT43_1 and triple lines had similar effects on AX they did differ in their contents of soluble sugars (increased in triple only) and on grain size (decreased in triple only). Both sets of transgenic lines had decreased grain hardness, indicating effects on cell wall mechanics. These results, and previously published studies of RNAi suppression of GT43_2 and GT47_2 and of a triple mutant of GT43_2, are consistent with the model of xylan synthase comprising three subunits one of which (GT47_2) is responsible for catalysis with the other two subunits being required for correct functioning but indicate that separate xylan synthase complexes may be responsible for the synthesis of populations of AX which differ in their structure and solubility.

Genome Sequencing-based Coverage Analyses Facilitate High-resolution Detection of Causal Deletions in Gamma-Irradiated Wheat Mutants

BackgroundGamma-irradiated mutants of hexaploid wheat, Triticum aestivum L., have been providing novel and agriculturally important traits and are used for breeding materials. However, identification of causative genomic regions of mutant phenotypes was challenging due to 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 hexaploid wheat.ResultsTo investigate whether genome sequencing approach can effectively detect structural variations such as deletions that are frequently caused by gamma irradiation, we selected a grain-hardness mutant from gamma-irradiated population of Japanese elite wheat cultivar “Kitahonami”. It is known that a Hardness (Ha) locus including puroindoline protein-encoding genes Pina-D1 and Pinb-D1 on the short arm of chromosome 5D mainly regulates the grain hardness variation in common wheat. We performed short-read genome sequencings of the wild-type and the grain-hardness mutant, and then aligned their short reads to the reference genome of wheat cultivar “Chinese Spring.” The genome-wide comparisons of depth-of-coverage between wild-type and the mutant detected a ~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 crosse between wild-type and the mutant. The large deletion in the region including the Ha locus was exactly associated with the mutant phenotype, indicating that genome sequencing approach is powerful and efficient to detect a causal deletion of a gamma-irradiated mutant. We also investigated a pre-harvest sprouting tolerance mutant and identified a 67.8 Mbp deletion on chromosome 3B where Viviparous-B1 and GRAS family transcription factor are located. Co-dominant markers designed to detect the deletion-polymorphism clearly confirmed an association with the low germination rate led to pre-harvest sprouting tolerance. ConclusionsShort-read-based genome sequencings of gamma-irradiated mutants facilitate the identification of large deletions responsible for mutant phenotypes when combined with segregation analyses in progeny populations. The method we adopted in this study allows the effective application of mutants with agriculturally important traits to breeding with marker-assisted selection.

Application of the descriptor-profile method in modeling the recipes of a preserved food using sprouted grain and malt extract

The article reflects the possibilities of using the descriptor-profile method in modeling recipes of functional food products taking into account the consumer preferences. Preserved foods using sprouted bare-grained oats or wheat and barley-malt extract served as samples for research. The simulation of the consumer preferences of the preserved product was carried out using a descriptor-profile method of tasting analysis. There were thirty-two features of descriptors identified for assessing organoleptic indicators and emotional customers’ perception of the product. A visual model of the consumer preferences of the preserved product was formed. The intensity and significance of each descriptor were determined. Influence of share of sprouted grain and malt extract on consumer preferences of preserved product was studied. Increasing the share of sprouted grain in the product reduced the coverage of the grain with the extract, the pallor and hardness of the grain, the intensity of brown color and the presence of malt-apple aroma. An "ideal" portrait of the product has been developed taking into account the strengths and weaknesses of the product, allowing to design organoleptic indicators at the stage of product development. High consumer preferences of the preserved product – a harmonious sweet taste with slight sourness, malt-apple-honey aroma, moderate grain hardness, lack of bitterness, – were achieved with 40% – 50% sprouted grain and 50% – 60% extract.

Modernization of information-measuring systems for grain processing

The paper discusses the basic operation principles of information-measuring systems for optimization wheat grain processing. The quality of grain processing products (cereals, flour, etc.) is influenced by both weather and climatic factors and grinding technologies. The modern development of information technologies makes it possible to modernize the existing information-measuring systems for grain processing and create new ones through the development of algorithms for analyzing the physical characteristics of the grain mass. During the study, test grinding of wheat grains of different varieties was carried out in a laboratory mill. To increase the yield of the finished product, digitalization of the selection of optimal grain separation modes was used. The obtained mathematical models allow predicting the quality of grain separation in separators of various types. The digitalization of the grain processing industry includes the use of artificial neural networks to analyze images of the grain mass using computer vision algorithms. It is promising to increase the information content of granulometric analysis using modern intelligent (information-measuring) systems. For the classification of wheat according to the milling properties, it is proposed to use the grain hardness. The studies used computer vision and artificial neural networks to find and organize the particles of grain grinding by geometric properties. The characteristics of the contours of the images of the grinding particles were taken into account. The values obtained by the developed information-measuring system were compared with that obtained using the Russian State Standard GOST methods. The error in assessing the grain hardness by the new method does not exceed 3.5%. The use of modern information tools allows improving the quality of wheat grain processing.

The effect of mutations in the alleles Gli-B1b and Gli-B1l on grain quality indices of common wheat

Aim. The aim of this study was to analyze quality indices in mutants at gliadin loci developed on the basis of the common wheat cultivar Bezostaya 1. Methods. Acid polyacrylamide gel electrophoresis and SDS-electrophoresis of storage proteins were performed to check mutations. Grain quality indices (SDS sedimentation volume, grain hardness, seed plumpness, and grain protein content) were analyzed: Results. Both mutants at Gli-R1 with the intensified secalin component and with the changed mobility of the secalin component showed lower grain hardness in comparison with the respective non-mutant lines. The mutation of the allele Gli-B1b causing the absence of synthesis of the g-gliadin and the minor w-gliadin resulted in the decrease in grain hardness and in the increase in the SDS-sedimentation volume. Seeds of the Gli-B1b mutant with the absence of synthesis of the major w-gliadin were less plump and showed higher protein content than in the non-mutant line. Conclusions. The effects of mutations of the allele Gli-B1b associated with the absence of certain gliadin components and Gli-R1 mutations on grain quality indices were revealed. Keywords: Triticum aestivum, gliadins, secalins, SDS-sedimentation, grain hardness.