The effect of genotype and environment on the fatty acid content of barley (Hordeum vulgare L.) grains

Abstract A comparison was made of the content of total and some individual fatty acids in grains of nine barley varieties grown at six sites in Belgium. The varieties represented six- and two-rowed winter types and two-rowed spring types. The results showed that the winter types contain more linolenic acid (C18 : 3) than spring types and that six-rowed barleys have less total fatty acids than two-rowed barleys, due mainly to a low concentration of palmitic (C16:0), oleic (CI8 : 1) and linoleic (C18 : 2) acids. Analysis of variance showed that fatty acid content is affected by both the genotype and the environment and multiple regression analysis suggested that weather conditions before and after flowering affected lipid composition.     

A DNA marker closely linked to the <Emphasis Type="Italic">vrs1</Emphasis> locus (row-type gene) indicates multiple origins of six-rowed cultivated barley (<Emphasis Type="Italic">Hordeum vulgare</Emphasis> L.)

The origin of six-rowed cultivated barley was studied using a DNA marker cMWG699 closely linked to the vrs1 locus. Restriction patterns of the PCR-amplified product of the cMWG699 locus were examined in 280 cultivated (Hordeum vulgare ssp. vulgare) and 183 wild (H. vulgare ssp. spontaneum) barleys. Nucleotide sequences of the PCR products were also examined in selected accessions. Six-rowed cultivated barleys were divided into two distinct groups, types I and II. Type I six-rowed cultivated barley was distributed widely while type II six-rowed cultivated barley was found only in the Mediterranean region. The type I sequence was also found in a wild barley accession from Turkmenistan whereas the type II sequence was also found in a two-rowed cultivated barley from North Africa and a wild barley from Morocco. These results suggested that the six-rowed type I and II barleys were derived from two-rowed type I and II barleys, respectively, by independent mutations at the vrs1 locus. Received: 3 November 2000 / Accepted: 17 April 2001     

On the origin of Spanish two-rowed barleys

To investigate the phylogenetic origin of Spanish two-rowed barleys, we studied 44 accessions of old land-races both morphologically and biochemically to ascertain their similarity with 51 entries of old cultivars and land-races of widespread origin across Europe. They were also compared with 20 accessions of Hordeum spontaneum from the Mediterranean basin and other regions of its distribution range, 14 accessions of Moroccan cultivated six-rowed barley land-races, and different six-rowed Spanish and two-and six-rowed European cultivars. CM-(trypsin inhibitors and subunits of the barley tetrameric -amylase inhibitor) proteins and hordeins, all of which are endosperm proteins, were used as biochemical markers. The appearance of separate clusters of the Spanish barleys in the numerical classifications for both protein systems as a result of the existence of characteristic gene combinations that do not exist in entries from other origins permitted us to postulate the existence of local ancestors for most of the Spanish two-rowed barleys studied, and, therefore, a possible in situ domestication.     

Distribution of MWG699 polymorphism in Spanish European barleys.

The STS marker MWG699/TaqI is closely linked to the vrs1 locus and has been proposed as a marker of domestication in barley. This study included 257 cultivated barleys of both two- and six-rowed varieties, mainly from the western Mediterranean region. These included many landraces from the Spanish barley core collection, Moroccan landraces, and a set of accessions from other European countries. Restriction analysis of amplified DNA revealed three alleles, as previously described. Most of the two-rowed entries had the same allele, type K. Six-rowed entries showed both types A and D. Indeed, type D was widespread among Spanish landraces and commercial varieties from central Europe. It was also found in some two-rowed landraces originating from Spain and Morocco. Barleys with the D haplotype were predominantly winter types, whereas the A haplotype was evenly distributed among spring and winter types. These results support the existence of two different genetic sources among six-rowed Spanish landraces.     

On the origin of six-rowed barley with brittle rachis, agriocrithon [Hordeum vulgare ssp. vulgare f. agriocrithon (Aberg) Bowd.], based on a DNA marker closely linked to the vrs1 (six-row gene) locus

The origin of six-rowed cultivated barley has been revealed to be more complex since the discovery of agriocrithon, a six-rowed barley with brittle rachis. The present study investigates whether such six-rowed brittle barley is wild or hybrid in nature, by analyzing genetic diversity at the cMWG699 marker locus, which is closely linked to the vrs1 (six-row gene) locus. DNA sequence analysis for 42 accessions showed only three types in six-rowed brittle barleys; in contrast, nine sequence types were found in ten wild barleys, ssp. spontaneum, in our previous study. Nucleotide diversities for the six-rowed brittle barley were 2.8–4.5 times lower than that for the ssp. spontaneum at this marker locus. The three sequence types found in the six-rowed brittle barley also appeared in the six-rowed cultivated barley. A cross-allelism test confirmed that the six-rowed character of the six-rowed brittle barley was controlled by the vrs1 locus. The nucleotide diversity and genealogy demonstrated that f. agriocrithon does not have the same level of diversity as found in wild barley, ssp. spontaneum. Consequently, f. agriocrithon does not appear to represent genuinely wild populations, but more probably originated from hybridization between ssp. spontaneum and six-rowed cultivated barley.     

RAPD Analysis and the Probable Evolutionary Route of Wild Relatives of Barley from China

he genetic relationships among 12 wild relatives and cultivar of barley ( Hordeum vulgare L.) as well as 1 perennial wild barley grass (H. brevisubulatum (Trin.) Link) from China were investigated by RAPD analysis. 36 out of 63 arbitrary primers produced 285 distinctive bands in total, 219 of which were polymorphic. Clearly resolved bands were treated as independent characters and scored for their presence or absence in a binary data matrix. Simple matching coefficients and Nei's similarity coefficients were calculated respectively. Dendrograms were generated by using the PHYLIP 3.5c software. The results revealed that the cultivated barley and their wild relatives from China were clustered into one group, among which, the two-rowed wild relatives of barley ( H. vulgare L. ssp. spontaneum (Koch) Hsü) and the six-rowed wild forms (H. vulgare L. ssp. agriocrithon (Aberg) Hsü) were respectively clustered into different subgroups. It was considered that wild relatives of barley from China were subspecies of H.vulgare. And it was proposed that the cultivated barley was originally evolved from the two-rowed wild barley. The retrogressive two-rowed wild barley and the bottle-shaped wild forms (H. vulgare L. ssp. agriocrithon var. lagunculiforme Bakht Hsü) were the intermediate types in the evolutionary route from the two-rowed wild barley to the six-rowed wild forms and eventually evolved to the cultivated barley.     

Genetic diversity analysis of barley landraces and cultivars in the Shanghai region of China

We analyzed the genetic diversity of 115 barley germplasms, including 112 landraces and three new barley cultivars grown in the Shanghai region, using a set of 11 SSR markers. Sixty-six alleles were observed at the 11 SSR loci, ranged from three to ten, with a mean of six alleles per locus. The polymorphism information content ranged from 0.568 to 0.853, with a mean of 0.732, indicating considerable genetic variation in barley in the Shanghai area. Clustering analysis indicated that these barley accessions could be divided into two categories (A and B). Ninety-seven six-rowed barley cultivars were classified in the A category; sixteen two-rowed and two six-rowed barley cultivars were classified in the B category. This demonstrated genetic differences between two-rowed and six-rowed barley varieties. In addition, we found that the three new barley cultivars are closely related.     

QTLs affecting kernel size and shape in a two-rowed by six-rowed barley cross

The suitability of barley ( Hordeum vulgare L.) grain for malting depends on many criteria, including the size, shape and uniformity of the kernels. Here, image analysis was used to measure kernel size and shape attributes (area, perimeter, length, width, F-circle and F-shape) in grain samples of 140 doubled-haploid lines from a two-rowed (cv Harrington) by six-rowed (cv Morex) barley cross. Interval mapping was used to map quantitative trait loci (QTLs) affecting the means and within-sample standard deviations of these attributes using a 107-marker genome map. Regions affecting one or more kernel size and shape traits were detected on all seven chromosomes. These included one near the vrs1 locus on chromosome 2 and one near the int-c locus on chromosome 4. Some, but not all, of the QTLs exhibited interactions with the environment and some QTLs affected the within-sample variability of kernel size and shape without affecting average kernel size and shape. When QTL analysis was conducted using data from only the two-rowed lines, the region on chromosome 2 was not detected but QTLs were detected elsewhere in the genome, including some that had not been detected in the analysis of the whole population. Analysis of only the six-rowed lines did not detect any QTLs affecting kernel size and shape attributes. QTL alleles that made kernels larger and/or rounder also tended to improve malt quality and QTL alleles that increased the variability of kernel size were associated with poor malt quality.     

Influence of Age on the Fatty Acid Composition of Breast and Thigh Muscles of Male Turkeys

Large White male turkeys were sacrificed at 4-week intervals from 4 to 28 weeks of age to study the fatty acid distribution in lipid of breast and thigh muscles. A total of 70 turkeys were sampled for this experiment.

Fatty acid distribution varied with advancing maturity and between muscle types. The most abundant fatty acids in the tissues were those with carbon chain lengths of 15:0, 16:0, 18:0, 18:1, 18:2, 20:4 and 24:0. Thigh muscle contained significantly more linoleate (18:2) than did breast. Larger proportions of pentadecanoic (15:0), arachidonic (20:4) and lignoceric (24:0), however, appeared in breast. Indications of minor fatty acids appeared on the chromatograms, but their low concentrations made their estimation and identification difficult.     

Identification of marker-trait associations in the German winter barley breeding gene pool (Hordeum vulgare L.)

A genome-wide association mapping approach for grain yield and traits of high agronomic relevance was carried out on basis of a set of 61 six-rowed and 48 two-rowed German winter barley (Hordeum vulgare L.) cultivars representing breeding progress in the period 1959?C2003. Extensive phenotyping was conducted in field trials carried out at 12 locations in 3?years. Heritability was estimated at between 0.45 for grain yield and 0.94 for grains per spike. By using the Illumina Golden Gate Bead Array technology, 833 single nucleotide polymorphisms with an allele frequency higher than 5% were obtained. Linkage disequilibrium on the whole genome extends to 7.35?cM. Based on a mixed linear model approach taking into account the population structure estimated on the basis of 72 simple sequence repeat markers covering the whole barley genome, 91 significant marker-trait associations were detected, corresponding to 48 different genomic regions.     

Exploitation of yield stability in barley

Key message

Analyses of registration trials of winter barley suggested that yield and yield stability can be enhanced by developing hybrid instead of line varieties.

Abstract

Yield stability is central to cope with the expected increased frequency of extreme weather conditions. The objectives of our study were to (1) examine the dimensioning of field trials needed to precisely portray yield stability of individual winter barley (Hordeum vulgare L.) genotypes, (2) compare grain yield performance and yield stability of two-rowed lines with those of six-rowed lines and hybrids, and (3) investigate the association of various agronomic traits with yield stability. Static and dynamic yield stability as well as grain yield performance was determined in five series of 3-year registration trials of winter barley in Germany. Each series included 4 or 5 six-rowed hybrids, 40–46 six-rowed inbred lines, as well as 42–49 two-rowed inbred lines. The genotypes were evaluated in 10–45 environments, i.e. year-by-location combinations. We found that precise assessment of yield stability of individual genotypes requires phenotyping in at least 40 test environments. Therefore, selection for yield stability is not usually feasible since the required number of test environments exceeds the common capacity of barley breeding programs. Also, indirect improvement of yield stability by means of agronomic traits seemed not possible since there was no constant association of any agronomic trait with yield stability. We found that compared with line varieties, hybrids showed on average higher grain yield performance combined with high dynamic yield stability. In conclusion, breeding hybrid instead of line varieties may be a promising way to develop high yielding and yield stable varieties.     

Photosynthesis and Transpiration in Leaves and Ears of Wheat and Barley Varieties

Carbon exchange rate (CER) and transpiration were measured inflag leaves, whole ears, glumes (referring to the total areaof glumes and lemmas) and awns, in six hexaploid spring wheats(Triticum aestivum L.), three cultivated tetraploid spring wheats(T. turgidum L.), four wild tetraploid wheats (T. dicoccoides),eight six-rowed barleys (Hordeum vulgare L.) and five two-rowedbarleys (H. vulgare L.). Differences between varieties and between species in total earCER and transpiration were associated largely with differencesin ear surface area rather than with rates per unit area. Ratesof CER and transpiration per unit area of ears were 40–80%of those of flag leaves, depending on the species. However, since ear surface area was greater than flag leaf areaby a factor of 1.1, 3.9, 5.5 and 4.4, in hexaploid wheat, tetraploidwheat, six-rowed barley, and two-rowed barley, respectively,total ear CER reached up to 90% of that of the flag leaf. The contribution of awns to total ear CER depended largely ontotal awn surface area per ear, rather than on CER per unitawn area. Awns contributed about 40–80% of total spikeCER, depending on the species, but only 10–20% of spiketranspiration. The disproportionately small contribution ofawns to ear transpiration was caused by the very low rate oftranspiration per unit area of awns. Thus, while transpirationratio (CER/transpiration) was about the same in flag leavesand glumes, it was higher by several orders of magnitude inthe awns. A large amount of awns in the ear is therefore a drought adaptiveattribute in these cereals, for which tetraploid wheat exceededhexaploid wheat and six-rowed barley exceeded two-rowed barley. Key words: Carbon exchange rate, Transpiration, Barley, Wheat     

Genetic mapping of the labile (lab) gene: a recessive locus causing irregular spikelet fertility in labile-barley (Hordeum vulgare convar. labile)

Key message

The recessive labile locus mapped on chromosome 5HL causes irregular spikelet fertility and controls floret development as well as row-type in barley.

Abstract

The labile-barley displays a variable number of fertile spikelets at each rachis internode (0–3 fertile spikelets/rachis internode) which is intermediate between that observed in two- or six-rowed types. Previous re-sequencing of Vrs1 in 219 labile-barley (Hordeum vulgare L. convar. labile) accessions showed that all carried a six-rowed specific allele. We therefore hypothesized that this seemingly random reduction in spikelet fertility is most likely caused by the labile (lab) locus, which we aimed to phenotypically and genetically define. Here, we report a detailed phenotypic analysis of spikelet fertility in labile-barleys in comparison to two- and six-rowed genotypes using scanning electron microscopy analysis. We found that the first visible morphological deviation occurred during the stamen primordium stage, when we regularly observed the appearance of arrested central floral primordia in labile but not in two- or six-rowed barleys. At late stamen and early awn primordium stages, lateral florets in two-rowed and only some in labile-barley showed retarded development and reduction in size compared with fully fertile lateral florets in six-rowed barley. We used two F₂ mapping populations to generate whole genome genetic linkage maps and ultimately locate the lab locus as a recessive Mendelian trait to a 4.5–5.8 cM interval at approximately 80 cM on chromosome 5HL. Our results will help identifying the role of the lab gene in relation to other spikelet fertility factors in barley.     

QTL analysis of agronomic traits in barley based on the doubled haploid progeny of two elite North American varieties representing different germplasm groups

A better understanding of the genetics of complex traits, such as yield, may be achieved by using molecular tools. This study was conducted to estimate the number, genome location, effect and allele phase of QTLs determining agronomic traits in the two North American malting barley (Hordeum vulgare L.) quality variety standards. Using a doubled haploid population of 140 lines from the cross of two-rowed Harrington×six-rowed Morex, agronomic phenotypic data sets from nine environments, and a 107-marker linkage map, we performed QTL analyses using simple interval mapping and simplified composite interval mapping procedures. Thirty-five QTLs were associated, either across environments or in individual environments, with five grain and agronomic traits (yield, kernel plumpness, test weight, heading date, and plant height). Significant QTL×environment interaction was detected for all traits. These interactions resulted from both changes in the magnitude of response and changes in the sign of the allelic effect. QTLs for multiple traits were coincident. The vrs1 locus on chromosome 2 (2H), which determines inflorescence row type, was coincident with the largest-effect QTL determining four traits (yield, kernel plumpness, test weight, and plant height). QTL analyses were also conducted separately for each sub-population (six-rowed and two-rowed). Seven new QTLs were detected in the sub-populations. Positive transgressive segregants were found for all traits, but they were more prevalent in the six-rowed sub-population.QTL analysis should be useful for identifying candidate genes and introgressing favorable alleles between germplasm groups. Received: 18 August 2000 / Accepted: 15 December 2000     

Spatial and temporal variation of the fatty acid composition of Patella spp. (Gastropoda: Prosobranchia) soft bodies and gonads

This study evaluated the effects of season and spatial distribution on the fatty acid composition of Patella depressa gonads and Patella spp. soft body tissue. The results show that the quantitatively most important fatty acids were the saturated fatty acids (SFA) 16:0, 14:0 and 18:0; the monounsaturated fatty acids (MUFA) 18:1(n-7), 18:1(n-9), 16:1(n-7) and 20:1(n-9) and the polyunsaturated fatty acids (PUFA) eicosapentaenoic acid (EPA 20:5(n-3)), and arachidonic acid (ARA 20:4(n-6)). P. depressa and P. ulyssiponensis soft body fatty acid profiles revealed significant differences between sexes; males showed significantly higher percentages of PUFA, highly unsaturated fatty acids (HUFA), (n-3) fatty acids and ARA, while in females significantly higher proportions of MUFA were found. Analysis of variance on the fatty acid composition of P. depressa gonads revealed significant differences between sexes, which were more marked than when the whole body was analysed. Males showed a significantly higher percentage of PUFA, HUFA, fatty acids from the (n-3) and (n-6) series, ARA and EPA, while females were seen to have higher proportions of SFA, MUFA and total fatty acid methyl esters (FAME). Some variability was seen to occur due to shore location and seasons, but these effects were not so obvious.     

Low responsiveness of six-rowed genotypes to androgenesis in barley does not have a pleiotropic basis.

A heterozygous mutant for the two- and six-rowed character was isolated in the barley cultivar Igri through application of sodium azide to isolated microspore cultures and posterior regeneration. Six-rowed and two-rowed homozygotic plants were subsequently identified in the self-pollinated M2 progenies of the original heterozygous M1. Detailed molecular markers confirmed the isogenic nature of this recovered mutant and the original cultivar Igri. A comparative study of the anther culture response of this six-rowed induced mutant vs. diploid 'Igri' was performed to assess whether the two- or six-rowed gene influences anther culture response in barley through a pleiotropic effect or via linkage disequilibrium. No significant differences for any of the recorded variables throughout the in vitro regeneration process were detected between the 'Igri' six-rowed mutant and any of their two-rowed isogenic lines. This suggests that row-type association with anther culture response in barley cultivars is due to the effect of a tight linkage with other genes directly responsible for androgenic response.     

Comparison of the internal transcribed spacer region (ITS) of the ribosomal RNA genes in wild and cultivated two and six-rowed barleys (Hordeum vulgare L.)

The ITS region of the ribosomal RNA genes from two and six-rowed cultivated barley (Hordeum vulgare subsp. distichon and H. v. subsp. hexastichon, respectively), and its two and six-rowed wild relatives (H. v. subsp. spontaneum and H. v. subsp. agriocrithon, respectively) was isolated and sequenced. The entire ITS region is 598 bp in the two-rowed taxa (H. v. subsp. distichon and H. v. subsp. spontaneum) and 599 bp in the six-rowed ones (agriochriton and hexastichon). The ITS1 is 217 bp in the six-rowed barleys (H. v. subsp. agriochriton and H. v. subsp. hexastichon) and 218 bp in the two-rowed barleys (H. v. subsp. distichon and H. v. subsp. spontaneum). The 5.8S region is 163 bp in all studied H. vulgare taxa. The ITS2 region is 217 bp in the two-rowed barleys (H. v. subsp. distichon and H. v. subsp. spontaneum) and 219 bp in the six rowed ones (H. v. subsp. hexastichon and H. v. subsp. agriochriton). The ITS sequence data of the studied taxa and that of three other wild Hordeum species (H. murinum, H. marinum and H. chilense) were aligned and a phylogeny tree was reconstructed using the Lasergene Program. H. v. subsp. spontaneum was appeared as the ancestor of all other H. vulgare taxa.     

Isolation of biochemical mutants using haploid mesophyll protosplasts of Hyoscyamus muticus

The question of whether membrane expansion, which is caused by anesthetics in animal systems, alters the lipid composition of plant cell membranes was investigated. We have measured the effects of several anesthetics on the relative amounts of the principal fatty acids from the polar lipids of barley (Hordeum vulgare L.) root membranes. Procaine, dibucaine, tetracaine, chloroform and, to a lesser degree, methanol increased the proportions of palmitic, stearic and oleic acids and decreased the proportions of linoleic and linolenic acids. Ethanol had no significant effect. Total amounts of the fatty acids from the polar lipids of roots in procaine solution decreased markedly so that all of the acids decreased in amount. The anesthetic was effective as soon as the roots were introduced to the solution and the changes progressed at constant rates for 6 h. Only the polar membrane lipids were altered; other lipids were not affected. Increased hydrostatic pressure of about 1.0 MPa largely prevented the anesthetic effects, including the decrease in the total amounts of the fatty acids. Hydrostatic pressure as high as 2 MPa had no effect per se on the membrane lipid composition. These results indicate that anesthetics cause expansion of the root membranes which results in the lipid changes. That a compositional change in the membrane lipids involves a conformational change such as expansion is an indication of the nature of the link between changes in the membrane lipids and changes in function of areas where hydrophilic ions permeate.Abbreviations 16:0 palmitic acid - 18:0 stearic acid - 18:1 oleic acid - 18:2 linoleic acid - 18:3 linolenic acid     

Digestibility of whole-crop barley and oat silages in dairy heifers

This study evaluated the digestibility of whole-crop cereal silage (WCCS) made from oats and six-rowed barley harvested at the heading, early milk and early dough stages, and two-rowed barley harvested at the early milk and early dough stages of maturity. The eight WCCSs were fed to 32 Swedish Red heifers in a changeover design over three periods of 28 days each. The heifers were first fed ad libitum for 17 days and then at 0.95 of ad libitum for 11 days of each period. During the last 5 days all faeces and orts were collected to determine the digestibility of the silages. Only the maturity stage effect was significant for the WCCS organic matter (OM) digestibility and the average OM digestibility was higher at the heading stage (698 g/kg) than at early milk (647 g/kg) and early dough (652 g/kg) stages of maturity. For neutral detergent fibre (NDF) digestibility the crop × maturity stage effect was significant. The NDF digestibility decreased from the heading to the early milk stage for both six-rowed barley (746 to 607 g/kg) and oats (698 to 596 g/kg). There was no further significant decrease in NDF digestibility for six-rowed barley at the early dough stage (577 g/kg), but for two-rowed barley it decreased from the early milk (682 g/kg) to the early dough (573 g/kg) stage, and also for oats the NDF digestibility was lowest at the early dough stage (507 g/kg). The decrease in NDF digestibility during maturation was to a large extent compensated by an increase in starch concentration in the crops. The starch digestibility was lower for six-rowed barley at early dough stage (948 g/kg) than at early milk stage (977 g/kg), and was also lower compared with oats (979 g/kg) at early dough stage. The average crude protein (CP) digestibility was higher at the heading (646 g/kg) and the early milk (642 g/kg) stages than at the early dough stage (599 g/kg), and oats had higher average CP digestibility (650 g/kg) than six-rowed (613 g/kg) and two-rowed (624 g/kg) barley. Delaying the harvest of WCCS from the heading to the early milk and dough stage of maturity will decrease the OM digestibility; as a result there is a decreased NDF digestibility.