Two-rowed Barley Research Articles

Yield, carbon isotope discrimination, canopy reflectance and cuticular conductance of barley isolines of differing glaucousness

The roles of wax bloom (glaucousness) in discrimination against stable isotope 13C (Δ) and yield were studied for 2 years on a pair of near-isogenic lines of two-rowed barley (Hordeum vulgare L.) differing in their degree of glaucousness of the spike and the upper vegetative parts of the plant other than leaf blades. The effects of glaucousness on canopy reflectance and cuticular conductance were also assessed. Plants were grown under fully irrigated and rainfed Mediterranean conditions for 2 years. Grain yield for both years and total straw biomass measured in the second year were higher in glaucous than nonglaucous lines under both irrigated and rainfed conditions. Δ followed the same pattern in both grain and straw with the highest values in the glaucous line under irrigation and the lowest in the non-glaucous line under rainfed conditions. Differences in yield and Δ between the lines were greater under irrigated than rainfed conditions. The higher Δ of the glaucous line suggests that these plants had lower transpiration efficiency (net photosynthesis to transpiration ratio) than the non-glaucous line in the long term. Canopy reflectance at some of the wavelengths of the PAR region (400–700 nm) was significantly higher in the glaucous than in the non-glaucous line under both irrigated and rainfed conditions. Rainfed conditions also increassed canopy reflectance in the PAR region. No significant effect of either glaucousness or water regime was observed in cuticular conductance or amount of cuticular waxes of the flag leaf blades or the ear.

Yield, carbon isotope discrimination, canopy reflectance and cuticular conductance of barley isolines of differing glaucousness

The roles of wax bloom (glaucousness) in discrimination against stable isotope 13 C (A) and yield were studied for 2 years on a pair of near-isogenic lines of two-rowed barley (Hordeum vulgare L.) differing in their degree of glaucousness of the spike and the upper vegetative parts of the plant other than leaf blades. The effects of glaucousness on canopy reflectance and cuticular conductance were also assessed. Plants were grown under fully irrigated and rainfed Mediterranean conditions for 2 years. Grain yield for both years and total straw biomass measured in the second year were higher in glaucous than non-glaucous lines under both irrigated and rainfed conditions. Δ followed the same pattern in both grain and straw with the highest values in the glaucous line under irrigation and the lowest in the non-glaucous line under rainfed conditions. Differences in yield and A between the lines were greater under irrigated than rainfed conditions. The higher Δ of the glaucous line suggests that these plants had lower transpiration efficiency (net photosynthesis to transpiration ratio) than the non-glaucous line in the long term. Canopy reflectance at some of the wavelengths of the PAR region (400-700 nm) was significantly higher in the glaucous than in the non-glaucous line under both irrigated and rainfed conditions. Rainfed conditions also increassed canopy reflectance in the PAR region. No significant effect of either glaucousness or water regime was observed in cuticular conductance or amount of cuticular waxes of the flag leaf blades or the ear.

Effects of Sulfur Dioxide on Apparent Photosynthetic Rate in Winter Cereals.

Invisible injury caused by air pollution is known to make photosynthesis decrease, and thus yields decrease. The purpose of this investigation was to make clear the effects of sulfur dioxide on winter cereals, which included 4 spcies and 67 cultivars. Sulfur dioxide was supplied at the rate of 2.6mg SO2m-3 (about 1.0 ppm v/v)for 30 min and then displaced with clean air for 30 min. The aparent photosynthetic rate of individual plants was continuously measured at the booting stage of each cultivar. In all plants, apparent photosynthetic rates were depressed by the application of sulfur dioxide. The magnitude of the of the depression in apparent photosynthesis was observed in the following order : naked barley, 45.6%>wheat, 38.6%>six-rowed barley, 31.5%>two-rowed barley, 28.4%. Nearly 90% of recovery in apparent photosynthesis was observed for all entries. In conclusion, injurious effects of sulfur dioxide on apparent photosynthesis were different among species of winter cereals. Naked barley was most susceptible to SO2 stress, and two-rowed barley was most tolerant.

Comparative performance of winter and spring malting barleys in semiarid growing conditions

In Europe, during the 1960s, mainly two-rowed spring barley was used for malting. Traditionally, spring malting barley was produced in regions with moderate temperatures and adequate rainfall throughout the growing season. Winter malting barley, on the other hand, was mostly grown in the milder arid and semiarid parts of Europe. Due to global climatic changes and its higher yield, winter malting barley is now increasing in acreage in the traditional spring barley regions. Our study included a comparative analysis of several grain and malt characters of the winter and spring malting barley grown under the agroecological conditions of the Vojvodina Province, Yugoslavia. One thousand grain weight was shown to be approximately the same for both growth habits, whereas winter malting barley proved to have a higher hectoliter mass than the spring one. In those years that were less favorable for spring barley production, winter malting barley had better quality characters, namely a higher fine extract content, a better malt modification, and a lower malt protein content.

Optimizing anther culture for barley breeding

Bailey anther culture methods were optimized for the production of doubled haploid lines from Finnish spring barley (Hordeum vulgare) breeding material. 22 F1 -progenies of two-rowed barley cultivars (‘Bonus’, ‘lnari’, Jo1610, ‘Kustaa’, ‘Kymppi’, ‘Prisma’) and six-rowed barley cultivars (‘Arve’, ‘Botnia’, ‘Larker Mutant’, OB264, ‘Rolfi’, WW7860) were used for the experiments. The effect of basic induction media, pretreatment on mannitol medium, density of anthers, incubation temperature and light regime were tested. Pretreatment of anthers for 4 days on medium containing 0.175 M mannitol was beneficial for all 8 genotypes tested and increased production of green plants per 100 anthers from 26% to 74% for the best genotype (‘lnari’ x ‘Kymppi’ F1). A lower anther density (1.6 anthers per cm2) was better than a more dense one. A modified MS-medium with ammonium nitrate partly replaced with glutamine (MMS-MG) was slightly better than a medium based on N6 salts (N6-MG), and addition of 100 μM silver nitrate reduced both plant and green plant production. No significant differences were observed between the effects of incubation temperatures (20°C vs. 25°C) or the light regime (darkness vs. weak light) during incubation of anthers. In each experiment the genotypic effect was prominent and the recalcitrance of some genotypes was apparent. Green plants were produced however from all genotypes.

Pathotypes of Cochliobolus sativus on Barley in North Dakota.

Spot blotch, caused by Cochliobolus sativus, has become an important disease on two-rowed barley cultivars in North Dakota. Information on the variability of virulence in C. sativus is essential for the development of spot blotch-resistant barley germ plasm. To establish the number and distribution of C. sativus virulence types in North Dakota, 22 isolates from the state were evaluated for their virulence on three differential barley genotypes: ND 5883, Bowman, and ND B112. Eleven additional isolates from Minnesota, South Dakota, Nebraska, Colorado, Japan, and China were included for comparison. Three pathotypes were identified from the thirty-three isolates tested based on the infection responses of the three host genotypes. These pathotypes were designated 0, 1, and 2 according to the coded triplet system of nomenclature. In North Dakota, pathotype 0 (exhibits low virulence on all three differentials) comprised 65%, pathotype 2 (exhibits high virulence on Bowman and low virulence on ND 5883 and ND B112) comprised 25%, and pathotype 1 (exhibits high virulence on ND 5883 and low virulence on Bowman and ND B112) comprised 10% of the total number of barley isolates examined. Within North Dakota, pathotype 1 was found in the east-central and northeastern region only, whereas pathotypes 2 and 0 were distributed throughout the state where samples were taken. Isolates with the pathotype 1 virulence pattern were identified in Colorado, Nebraska, Japan, and China. The remaining isolates collected outside North Dakota were pathotype 0. The information obtained from this study will facilitate the deployment of effective resistance to C. sativus in barley.

Effect of sequential abrasion on starch composition of five cereals for ethanol fermentation

Five cereals were abraded successively on a Satake abrasive test mill to enhance the starch contents of the pearled grains to improve fermentation efficiency of fuel ethanol plants. Tempering the cereals to 12.5% and 15.0% moisture had no consistent effects on rates of grain mass removal by abrasion but final starch losses to the abraded fines could be minimized by optimizing grain moisture content. Increasing abrasion time from 10 to 55s increased the average grain mass removal from 3.5 to 19.5% in four hulless cereals but 70s of abrasion was needed to remove 32.6% of two-row barley to obtain a comparable starch content in the pearled grain. On a dry basis, the pearled grain starch levels were: Canadian Prairie Spring (CPS) red wheat (73.4%); CPS white wheat (72.2%); two-row barley (71.0%); fall rye (70.4%); and triticale (69.1%), which represented, on average, a 12% increase in starch content over those of the original grains. Ethanol yields per tonne of fermentation feedstock were increased by 6.5–22.5% as a result of abrasion, which would substantially increase ethanol plant throughput and grain fermentability.

Total, water-soluble and acid-soluble arabinoxylans in western Canadian barleys

Non-starch polysaccharides, such as β-glucan and arabinoxylan, are often implicated as a cause of the poor feeding value of barley for poultry. Levels of arabinoxylan in Canadian barley types, though, have not been thoroughly investigated. Total, water-extract and acid-extract arabinoxylan levels were determined for six-rowed (covered), two-rowed (covered) and hulless (both six- and two-rowed) barley (Hordeum vulgare) cultivars and genotypes grown in the 1991 Western Canadian Barley Cooperative Program. Analyses were performed using a dichromatic modification of the orcinol method. The six-rowed barley types contained significantly greater total, water-extract and acid-extract arabinoxylan concentrations than hulless or two-rowed types (P < 0.05). In hulless barley, total (P < 0.01), water-extract (P < 0.01), and acid-extract (P < 0.05) levels of arabinoxylan were, respectively, less than, greater than and similar to levels of arabinoxylan in samples of two-rowed barley. Environment had a significant effect on levels of water-extract (P < 0.01) and acid-extract (P < 0.05) arabinoxylan. Genetic differences affected the arabinoxylan content of cultivars and genotypes within each of the barley types (P < 0.05). Levels of acid-extract arabinoxylan were positively correlated with the viscosities of acid extracts of the barleys (P < 0.001). Key words: Arabinoxylan, barley, viscosity, acid-extract, pentosans

Sterility in Two-Rowed Barley Due to Boron Deficiency

Sterility in Two-Rowed Barley Due to Boron Deficiency

Fertile plant regeneration from cell suspension and protoplast cultures of barley (t Hordeum vulgare cv. Schooner)

Fertile plants were regenerated from both cell suspension and protoplast-derived cultures of the two-row barley, Hordeum vulgare L. cv. Schooner. Embryogenic calluses, derived from immature embryos, were used to establish suspension cultures. More than 100 plants, with variable seed set, have been regenerated from six embryogenic cell suspension cultures. Protoplasts isolated from three suspension cultures divided and when the resultant embryogenic proto-calluses were transferred to regeneration medium both green and albino shoots were produced. The green shoots were transferred to growth regulator-free medium and plantlets that developed strong root systems were potted in soil and grown to maturity in the glasshouse. Root tip analysis of plants regenerated from cell suspension cultures revealed the expected 2N = 14 complement of chromosomes. However, chromosomal analysis of protoplast-derived plants showed numerical variation among a proportion of the regenerants.

Effect of varied N rates and N timings on yield, N uptake and fertilizer N use efficiency of a six-row and a two-row winter barley

The effects of N rates and N timings on yield formation, N uptake at five growth stages and fertilizer N use efficiency of six-row and two-row winter barley were evaluated in field trials conducted from 1990/91 to 1992/93 at the TU Munich's research station Roggenstein. On average over 3 years the six-row cultivar yielded most at a total rate of 110 kg ha −1 N including an early application of 40 kg ha −1 N up to EC 30 (Zadoks scale). The two-row cultivar achieved maximum yield at a total rate of 140 kg ha −1 N including early applications of 70 kg ha −1 N up to EC 30. The highest yielding N-treatments of six-row barley regularly took up less nitrogen at EC 32 (95 kg ha −1 N on average) than the non-optimally fertilized treatments, whereas full exploitation of the yield potential of two-row barley was associated with higher rates of N-uptake at EC 32 (113 kg ha −1 N on average). Lodging did not occur in the trials conducted in 1991 and 1992 and no difference was detected between the two cultivars in fertilizer N use efficiency. With six-row barley the N treatment giving maximum yield also led to an optimum fertilizer N use efficiency. Full exploitation of the two-row barley yield potential was associated with suboptimal fertilizer N use efficiencies.

Registration of ‘Giza 127‘ Two‐Rowed Barley

Crop ScienceVolume 36, Issue 6 cropsci1996.0011183X003600060053x p. 1714-1714 Registration of Cultivars Registration of ‘Giza 127‘ Two-Rowed Barley A. A. El-Sayed, A. A. El-SayedSearch for more papers by this authorM. M. Noaman, Corresponding Author M. M. Noaman n/a@.dne Corresponding author.Search for more papers by this authorA. M. Sherbini, A. M. SherbiniSearch for more papers by this authorF. A. Asaad, F. A. AsaadSearch for more papers by this authorA. S. El-Gamal, A. S. El-GamalSearch for more papers by this authorA. O. El-Bawab, A. O. El-BawabSearch for more papers by this authorM. Megahed, M. MegahedSearch for more papers by this authorM. Abdel-Hameed, M. Abdel-HameedSearch for more papers by this authorE. E. Dessouki, E. E. DessoukiSearch for more papers by this author A. A. El-Sayed, A. A. El-SayedSearch for more papers by this authorM. M. Noaman, Corresponding Author M. M. Noaman n/a@.dne Corresponding author.Search for more papers by this authorA. M. Sherbini, A. M. SherbiniSearch for more papers by this authorF. A. Asaad, F. A. AsaadSearch for more papers by this authorA. S. El-Gamal, A. S. El-GamalSearch for more papers by this authorA. O. El-Bawab, A. O. El-BawabSearch for more papers by this authorM. Megahed, M. MegahedSearch for more papers by this authorM. Abdel-Hameed, M. Abdel-HameedSearch for more papers by this authorE. E. Dessouki, E. E. DessoukiSearch for more papers by this author First published: 01 November 1996 https://doi.org/10.2135/cropsci1996.0011183X003600060053xAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume36, Issue6November–December 1996Pages 1714-1714 RelatedInformation

Registration of ‘Giza 128‘ Two‐Rowed Barley

Crop ScienceVolume 36, Issue 6 cropsci1996.0011183X003600060054x p. 1715-1715 Registration of Cultivars Registration of ‘Giza 128‘ Two-Rowed Barley A. A. El-Sayed, A. A. El-SayedSearch for more papers by this authorM. M. Noaman, Corresponding Author M. M. Noaman n/a@.dne Corresponding author.Search for more papers by this authorF. A. Asaad, F. A. AsaadSearch for more papers by this authorA. M. El-Sherbini, A. M. El-SherbiniSearch for more papers by this authorA. O. El-Bawab, A. O. El-BawabSearch for more papers by this authorA. S. El-Gamal, A. S. El-GamalSearch for more papers by this authorM. Abdel-Hameed, M. Abdel-HameedSearch for more papers by this authorM. Megahed, M. MegahedSearch for more papers by this authorE. E. Dessouki, E. E. DessoukiSearch for more papers by this author A. A. El-Sayed, A. A. El-SayedSearch for more papers by this authorM. M. Noaman, Corresponding Author M. M. Noaman n/a@.dne Corresponding author.Search for more papers by this authorF. A. Asaad, F. A. AsaadSearch for more papers by this authorA. M. El-Sherbini, A. M. El-SherbiniSearch for more papers by this authorA. O. El-Bawab, A. O. El-BawabSearch for more papers by this authorA. S. El-Gamal, A. S. El-GamalSearch for more papers by this authorM. Abdel-Hameed, M. Abdel-HameedSearch for more papers by this authorM. Megahed, M. MegahedSearch for more papers by this authorE. E. Dessouki, E. E. DessoukiSearch for more papers by this author First published: 01 November 1996 https://doi.org/10.2135/cropsci1996.0011183X003600060054xAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume36, Issue6November–December 1996Pages 1715-1715 RelatedInformation

Regression analysis of yield stability is strongly affected by companion test varieties and locations — examples from a study of Nordic barley lines

The suitability of regression analysis for studying the phenotypic stability of grain yield was investigated using a collection of 220 Nordic barley lines. Linear regression explained 26-52% of the genotype x environment (GE) interactions in different groupings of the material. The regression coefficient, b i , measures the yield response of the i-th genotype to improved environmental conditions. Deviations from regression, S di (2) , have been used to estimate Tai's stability parameter, λ i , which is a measure of the phenotypic yield stability in the agronomic sense. Repeatability of b i , λ i , and grain yield was studied by means of correlations between estimates obtained in each experimental year. Yield had the highest repeatability, with correlations between years ranging from 0.57 to 0.85. In this study, regression coefficients and λ i -values were not repeatable, i.e. genotypes reacted differentially to the yearly climatic variations. Six-rowed (6r) barleys had higher responsiveness, but lower mean yields, than two-rowed (2r) barleys. This is partly due to the history of selection of 6r-barleys, which mainly originate from regions with low potential yield levels, i.e. Finland and Norway. In general, responsiveness and stability were not correlated with yield. The highest-yielding lines had b i ≈1. The response pattern of the different types of barleys used in this study show that responsiveness can be changed by recombination.

Regions of the Genome that Affect Agronomic Performance in Two‐Row Barley

Quantitative trait locus (QTL) main effects and QTL by environment (QTL × E) interactions for seven agronomic traits (grain yield, days to heading, days to maturity, plant height, lodging severity, kernel weight, and test weight) were investigated in a two‐row barley (Hordeum vulgare L.) cross, Harrington/TR306. A 127‐point base map was constructed from markers (mostly RFLP) scored in 146 random double‐haploid (DH) lines from the Harrington/TR306 cross. Field experiments involving the two parents and 145 random DH lines were grown in 1992 and/or 1993 at 17 locations in North America. Analysis of QTL was based on simple and composite interval mapping. Primary QTL were declared at positions where both methods gave evidence for QTL. The number of primary QTL ranged from three to six per trait, collectively explaining 34 to 52% of the genetic variance. None of these primary QTL showed major effects, but many showed effects that were consistent across environments. The addition of secondary QTL gave models that explained 39 to 80% of the genetic variance. The QTL were dispersed throughout the barley genome and some were detected in regions where QTL have been found in previous studies. Eight chromosome regions contained pleiotropic loci and/or linked clusters of loci that affected multiple traits. One region on chromosome 7 affected all traits except days to heading. This study was an intensive effort to evaluate QTL in a narrow‐base population grown in a large set of environments. The results reveal the types and distributions of QTL effects manipulated by plant breeders and provide opportunities for future testing of marker‐assisted selection.

The 5S rRNA gene units in ancestral two-rowed barley (Hordeum spontaneum C. Koch) and bulbous barley (H. bulbosum L.): sequence analysis and phylogenetic relationships with the 5S rDNA units of cultivated barley (H. vulgare L.).

5S rRNA genes from several accessions of Hordeum spontaneum and Hordeum bulbosum, wild relatives of cultivated barley, Hordeum vulgare, have been amplified by the polymerase chain reaction, cloned, and sequenced. Evaluation of aligned sequences along with principal coordinate analysis demonstrates that the two classes of 5S rDNA sequences found in cultivated barley, and subclasses (groups) of these sequences, can also be found in its closest wild relatives. The two classes of units, formerly categorized as containing short or long 5S rDNA repeats, are distinguishable by the presence or absence of a TAG repeating unit. Sequence comparisons of individual clones (units) isolated from different species have allowed us to confirm that orthology exists for several groups. This demonstration of orthologous groups suggests that the 5S rDNA sequence may be useful for further phylogenetic analysis in the genus Hordeum and possibly in the Triticeae.

Simple sequence repeat primers used in polymerase chain reaction amplifications to study genetic diversity in barley

In combination with oligonucleotides of arbitrary sequence, 5' anchored oligonucleotides based on simple sequence repeats were used in polymerase chain reaction amplifications to produce barley DNA fingerprints. The aim of this work was (i) to develop a simple nonradioactive experimental procedure to reveal polymorphism in regions containing SSRs, (ii) to determine the genetic nature of polymorphisms, and (iii) to investigate the efficacy of polymorphisms contained in such fingerprints in disclosing genetic relationships between 14 European barley cultivars with known pedigrees. Different 10-mer oligonucleotides containing a dinucleotide motif were used as single primers and also in pairs with 10-mer oligonucleotides of arbitrary sequence. Further, the arbitrary oligonucleotides were used as single primers to produce RAPDs. Thirteen combinations of primers containing either GT(CA)4 or GC(CA)4 were selected on the basis of number and intensity of scorable bands in silver-stained 7% polyacrylamide gels. Of the fragments scored, 58.4% were polymorphic. Inheritance of these random amplified microsatellite polymorphic fragments (RAMP) was studied in doubled-haploid lines from the F1 of 'Steptoe' x 'Morex'. Fifty percent of the primers generated codominant markers. Genetic similarities between cultivars were estimated from RAMP and RAPD data. Principal coordinate analysis performed on RAMP data revealed a clear separation of winter six-rowed, winter two-rowed, and spring two-rowed barley. The dendograms generated faithfully reflected the genealogies of the barley cultivars. RAPD failed to show clearly the germplasm sources of the experimental cultivars.

Cultivar Difference on Dry Matter Production and Grain Production in Two-rowed Barley of Warm Regions in Japan.

Cultivar difference on dry matter production and grain production in two-rowed barley (Hordeum distichum L. emend, LAMARK) of warm regions in Japan were investigated from 1987 to 1989. Fifteen Japanese cultivars and nineteen foreign cultivars in 1987/1988, and four Japanese cultivars and eleven foreign cultivars in 1988/1989 were grown under field conditions. The full heading stage of Japanese cultivars except New Golden and Kanto Nijyo 19 in 1987/1988 was in the early of April, but the foreign cultivars except WI-2727 was in the late of April. The top dry weight of Japanese cultivars was 615-1001 g m-2, and that of the foreign cultivars was 744∼1088 g m-2. The top dry weight of late maturing cultivars in the full heading stage was higher than that of early and middle maturing cultivars. The LAI of Japanese cultivars was 3∼4, and Nishinochikara was 4.97, higher than the early maturing cultivars. The maturing stage of Japanese cultivars except New Golden, Daisen Gold and Kanto Nijyo 19 was in the middle of May. The grain weight were 408∼544 g m-2. The harvest index (HI) of breeding cultivars in Japan in recent years was 41∼42 and that of Hakei 86-107 was 46.1.

Varietal Differences and Family Analysis of the Percentage of Hull-cracked Grains in Two-rowed Barley.

二条オオムギ48品種を岡山県倉敷市と群馬県新田町の2ヶ所で2ヶ年にわたって栽培し，側面裂反粒率の品種間差異を解析した.また，側面裂反粒率の高い吉系16と新田系22の祖先品種を供試して家系分析によって側面裂反粒率の遺伝性を解析した.側面裂反粒率は4条件の平均値で1%以下から67%まで広範な品種間差異を示し，分散分析の結果，品種と栽培地域の主効果ならびに品種と地域の交互作用が有意で，年次間差異も有意であった，側面裂反粒率が有意に高い倉敷では千粒重も明らかに大きかった.家系分析の結果，側面裂反粒の発生はいくつかの遺伝子が集積して表現される複合形質であることが明らかにされた.

Quantitative trait loci for grain yield and yield components in a cross between a six-rowed and a two-rowed barley

The positions of quantitative trait loci (QTL) for yield and yield components were estimated using a 85-point linkage map and phenotype data from a F1-derived doubled haploid (DH) population of barley. Yield and its components were recorded in two growing seasons. Highly significant QTL effects were found for all traits at several sites in the genome. A major portion of the QTL was found on chromosome 2. The effect of the alleles in locus v on thousand grain weight and kernels per ear explained 70–80% of the genetic variation in the traits. QTL × year interaction was found for grain yield. Several different QTL were found within the two-rowed DH lines compared to those found in the six-rowed DH lines. Epistasis between locus v and several loci for yield and yield components indicates that genes are expressed differently in the two ear types. This may explain the difficulties of selecting high yielding lines from crosses between two-rowed and six-rowed barley.