Jilal, A 2011, 'Assessment of genetically diverse international barley germplasm for development of food product applications', PhD thesis, Southern Cross University, Lismore, NSW.
Copyright A Jilal 2011
Barley landraces have experienced years of natural and farmer massal selection in favour of his particular trait of interest (food, feed or malt) without any scientific background on their performance, quality or inner properties. Eight hundred and seventy eight barley landraces, collected from farmers’ sites typically used for food belonging to forty three countries, were investigated to uncover the elite properties of this international barley landraces. Series of agro-morphological, physiological and quality analyses were performed. Greater genotype effect over environment for agro-morphological and physiological traits was detected by GGE Biplot analysis when considering cultivars grown under adverse environmental conditions of the two ICARDA’s experiment stations. Strong evident correlations between traits for individuals from different countries were observed (positive: grain yield and biomass; peduncle extrusion and peduncle length, negative: heading date with grain yield and peduncle properties. The wild relative Hordeum ssp spontaneum was clearly distinct from the cultivated barley as depicted with principal coordinate and cluster analyses. The geographical representation of the agro-morphological and physiological traits based on their averages could guide an efficient collection of a specific trait of interest (e.g. trait: material with high canopy temperature depression to be collected in Morocco, high fluorescence ratio in China and high chlorophyll content in Iran). Genetic diversity study of 304 subset barley landraces from 29 countries with twenty SSR markers was also conducted. Out of them, 19 highly polymorphic markers have identified three distinct germplasm pools: 1) Eastern Africa and South America, 2) Caucasus and 3) Central Asia, Near East, Northern Africa and Eastern Asia. Barley subspecies (H. vulgare ssp vulgare convar. vulgare, H. vulgare ssp vulgare convar. distichon, H.ssp spontaneum and H. vulgare ssp vulgare convar. vulgare f agriochrithon) were separated into three distinct groups (cultivated barleys, H.ssp spontaneum and H. vulgare ssp vulgare convar. vulgare f agriochrithon) leading to the possibility of rejection the hybrid origin of H. vulgare ssp vulgare convar. vulgare f agriochrithon.
Modernization of barley landraces, staple food used traditionally for making typical recipes, for food uses through assessing its food quality richness is indeed possible. Out of 878 barley landraces, 45 samples have been identified as being suitable for use in the production of pearled barley, barley flour and/or barley flakes. This project has disclosed the richness of the wild barley Hordeum ssp spontaneum in terms of protein content and β-glucans content. The significant correlation between protein content and the minerals Zn and Fe confirmedprevious reports in the literature. In addition, this work revealed that barley landraces are potential source β-glucans and micronutrients (i.e. Zn and Fe) thereby highlighting the potential for these landraces to be utilized in breeding programs that are targeting the enhancement of barley for use in food applications.
The genotype by environmental effect of ß-Glucan determined by Megazyme kit on a subset of 242 barley landraces from 31 countries grown during the cropping seasons 2005-2006 and 2006-2007 in two ICARDA’s contrasting environmental experiment stations was supported disclosing high ß-Glucan values in Eritrea, Palestine and Algeria.
Barley landraces were also characterized by high amylose content mainly the wild relative and by diverse viscosity properties leading to the possibility of developing food barley products like noodles or cookies. Correlation between amylose content and ß-Glucan was revealed same as soft kernel and viscosity parameters. This latter was also correlated positively with TKW and ß-Glucan and negatively with protein content. H.ssp spontaneum also features high viscosity values. The results spotlight the interest of barley landraces especially Hordeumssp spontaneum in food industries for making various food barley products with typical characteristics e.g. barley food rich in amylose content for obese patients.
The association studies of Granule Bound Starch Synthase I (GBSSI) and Starch Synthase IIa (SSIIa) genes single nucleotide polymorphisms (SNP) with food quality characteristics in barley, comprising amylose content, viscosity properties and physicochemical parameters, revealed many SNPs of GBSS1 and SSIIa genes that were significantly related to food quality traits and amongst them few ones have led to amino acid changing (amylose, amylopectin, hardness, β-glucans, viscosity parameters, plumpness, protein and zinc. From these results, barley landraces might be considered as source of food barley products development and SNPs starch genes (GBSSI and SSIIa) as tools for food quality traits changing via mutations at the appropriate associated SNP.