Carbon Isotope Discrimination and Productivity in Field-Grown Barley Genotypes

Five barley genotypes of different origins were used to examine the relationships between carbon isotope discrimination (Δ) and grain yield, yield components, dry aerial biomass and harvest index under rainfed and irrigated Mediterranean conditions. High positive correlations were found between Δ and grain yield and harvest index under both water conditions, suggesting that Δ may represent efficiency of dry matter partitioning to the grain. This hypothesis was also supported by the positive correlation found between Δ and thousand-grain weight when all the data were considered. The two drought-tolerant genotypes LM2887 and Tadmor presented the smallest difference between the two treatments for traits related to productivity as well as the highest Δ values. These results highlight the potential of Δ as a selection criterion in barley breeding in Mediterranean regions. They also encourage the study of the genetics of Δ and the identification of molecular markers linked to its variation in available progenies derived from crosses between the genotypes used in the present paper.     

Discovery,characterization and exploitation of Mlo powdery mildew resistance in barley

Summary Mlo resistance to barley powdery mildew is a relatively new kind of resistance. It was originally described in a powdery mildew resistant barley mutant in 1942 and has been mutagen-induced repeatedly since then. About 1970 it was also recognized in barley landraces collected in Ethiopia in the 1930s. It is unique in that 1) Mlo resistance does not conform to the gene-for-gene system; 2)mlo genes originating from different mutational events map as non-complementing recessive alleles in one locus; 3) all alleles confer the same phenotype, though with small quantitative differences; 4) it is effective against all isolates of the pathogen; and 5) the resistance is caused by rapid formation of large cell wall appositions at the encounter sites preventing penetration by the fungus. Powdery mildew isolates with elevated Mlo aggressiveness have been produced on barley in the laboratory, but have not been found in nature. Mlo resistance is considered very durable. The exploitation of Mlo resistance has been hampered by pleiotropic effects of themlo genes, vix. necrotic leaf spotting and reduced grain yield, but they have been overcome by recent breeding work. During the 1980s Mlo-resistant spring barley varieties have become cultivated extensively in several European countries, in 1990 on about 700,000 ha.     

The effect of anther orientation on microspore-derived plant production in barley (Hordeum vulgare L.)

Summary The effect of anther orientation on culture response has been examined in a range of barley cultivars of agronomic importance. Anther orientation did not significantly affect the percentage of anthers responding. However, orientation of the anthers in the up position with one lobe in contact with the medium significantly increased the number of green plants produced when compared to anthers cultured in the flat position. Green plantlet production was observed directly from embryoids i.e. without an intermediate callus phase. Cytological examination of the regenerants indicated that the majority of the plantlets possessed the normal barley karyotype. The implications of these results for Barley breeding are discussed.     

Variation in vegetative parameters related to the nitrogen economy of wild barley,Hordeum spontaneum,in Israel

Summary Hordeum spontaneum, the wild progenitor of cultivated barley, has previously been examined in various studies as a germplasm resource in breeding for grain protein content and related nutritional traits.The nitrogen content and dry weight of leaf and stem (stem plus sheath) at anthesis, and the final grain size and grain protein content were measured in 33 H. spontaneum and two H. vulgare genotypes. H. spontaneum was generally higher in nitrogen content of leaves and stems, but lower in dry weight at anthesis. Consistent with previous reports, the H. spontaneum genotypes were considerably higher in grain protein than the cultivars. There was wide variation between and within populations of H. spontaneum suggesting that for breeding purposes lines combining high vegetative nitrogen content, dry weight and grain protein content can be selected.Incumbent of the Seagram Chair for Plant Science     

The use of reversed-phase high performance liquid chromatography as an aid to the identification of European barley cultivars

Summary A reversed-phase high performance liquid chromatography (RP-HPLC) system was used to separate the storage proteins (hordeins) extracted from European barley cultivars. From a total of 38 barleys tested, 26 types of hordein patterns could be distinguished after RP-HPLC. This appears to be a marked improvement in resolution over that achieved in a similar survey of European barley cultivars using SDS polyacrylamide electrophoresis (32 hordein patterns resolved by SDS PAGE from a total of 160 spring and winter barleys tested).Different hordein patterns were resolved by RP-HPLC within each of two groups of barley previously classified by SDS PAGE as indistinguishable within groups (three distinct patterns identified in a total of five cultivars tested from group 1A and five patterns observed among eight cultivars from group 3B). Thus RP-HPLC achieves a higher resolution than undirectional electrophoresis and promises to be a valuable aid in the identification of European barley cultivars.     

The evaluation of superior Hordeum bulbosum L. genotypes for use in a doubled haploid barley breeding programme

Summary Eight Hordeum bulbosum selections were produced from a cross between Cb 2920/4 and Cb 2929/1, two genotypes widely used in doubled haploid breeding programmes. The selections were hybridized with barley to evaluate their ability to produce high proportions of well-differentiated haploid embryos compared with Cb 2929/1 as control. We report here an initial small-scale investigation followed by a larger-scale test in two different environments to assess seed setting, haploid embryo differentiation rates and VB hybrid formation. These VB embryos contain both parental sets of chromosomes and occur more frequently in the glasshouse during the winter. Two of the eight selections were identified as combining the desirable characteristics of both parents, namely high seed setting on cv. Vada which is partially incompatible with H. bulbosum, large numbers of well-differentiated haploid embryos and a low incidence of VB hybrids. The selections are available for release to interested research workers and plant breedersAbbreviations DH doubled haploid - VB a hybrid from H. vulgare x H. bulbosum which contains both parental sets of chromosomes     

Chlorophyll fluorescence transient as a genetic marker of productivity in barley

Summary The photosynthetic characteristics of the penultimate leaf in barley genotypes (reciprocal F1 combinations and varieties) were studied at the flowering stage in order to analyze the relationship between these traits and the biological yield and the economic yield. The biological yield was correlated with the leaf area whereas the economic yield was more dependent on the green area duration of the leaf or the combination of the two factors, leaf area and green area duration. The net photosynthesis per unit leaf area, determined at anthesis, was not a factor of productivity. On the other hand, the chlorophyll fluorescence (P), which was negatively correlated with the leaf area (+0.5) and with the combination of leaf area and green area duration (+0.5), was found to be a good marker of the economic yield. In view of its high heritability, it may provide an effective selection criterion.     

Interplot interference and the assessment of barley cultivars for partial resistance to leaf rust,Puccinia hordei

Summary The barley cultivars Akka, highly susceptible, and Vada, partially resistant to barley leaf rust, Puccinia hordei, were evaluated for the amount of leaf rust in five experimental field plot situations over three successive years. The field plot situations were: A) plots well isolated from each other by distance and non-leaf rust contributing host plants; B) adjacent plots of 4×41/2 m (18 rows); C) adjacent plots of 4×11/2 m (6 rows); D) adjacent plots of 4×1/4 m (1 row); E) adjacent plots of only one plant (cultivar mixtures).The sporulating leaf area of each plot was measured from samples of 20 tillers taken at random from each plot. In each year the difference in sporulating area between Akka and Vada was large to very large in the absence of interplot interference in the isolated plots, ranging from 150 to 2100 times. In the adjacent plots the partial resistance of Vada was greatly underestimated, 5 to 16 times in the situation B, 14 to 30 times in C, and 75 to 130 times in D and E.Testing lines or cultivars in adjacent plots is the standard procedure in use in breeding programs and in tests of cultivars for their agricultural value. To avoid such under estimation the following procedure is suggested. A few cultivars representing the known range of partial resistance and whose level of partial resistance is well known are evaluated together with the lines and cultivars whose partial resistance has to be assessed. This is demonstrated with a number of cultivars of which resistance values are know from the recommended variety lists for England and Wales. Cultivars have been assessed in Wageningen over four years together with the check cultivars Akka, Sultan, Julia and Vada representing the range of partial resistance with values (on a 1 to 10 scale) of 1, 3–4, 7 and 8 respectively, based on isolated plots experiments.     

Further evidence of polygenic inheritance of partial resistance in barley to leaf rust,Puccinia hordei

Summary The latent period (LP) is a crucial component of partial resistance. Five cultivars, L94, Sultan (Su), Volla (Vl), Julia (Ju) and Vada (Va), representing the known range in partial resistance and LP were crossed in a diallel, and the F₁, F₂ and F₃ tested. The LP effectuated by the five cultivars is about 9, 10^1/2, 10^1/2, 13 and 15^1/2 days, respectively. The crosses Su×L94, Vl×L94 and Ju×L94 had an F₂ positively skewed. Their F₂ means were similar or only slightly larger than the F₁ means. The F₂ frequency distributions in the crosses Vl×Su, Ju×Su and Ju×Vl were normal or nearly so with F₁ and F₂ means similar to each other and to the mid-parent value. The crosses involving Va as a parent again showed a positive skewness but with F₂ means considerably larger than the F₁ moans.Most F₂'s ranged from the low parent to the high parent values without transgression. In the crosses Va×L94 (reported earlier) and Ju×L94 the parental values were not recovered among 216 and 154 F₂ plants, respectively. The cross Ju×Va showed transgression beyond the low parent, Ju.From these data it is concluded, assuming no linkage, that seven loci are involved. The + alleles (governing a longer LP) are thought to be distributed over the parents as follows: % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGceaqabeaacaqGmb% GaaeyoaiaabsdacaqGGaGaaeiiaiaabccacaqGGaGaaeiiaiaabcca% caqGGaGaaeiiaiaab2cacaqGTaGaaeiiaiaabccacaqGGaGaaeiiai% aabccacaqGGaGaaeiiaiaabccacaqGTaGaaeylaiaabccacaqGGaGa% aeiiaiaabccacaqGGaGaaeiiaiaabccacaqGGaGaaeylaiaab2caca% qGGaGaaeiiaiaabccacaqGGaGaaeiiaiaabccacaqGGaGaaeiiaiaa% b2cacaqGTaGaaeiiaiaabccacaqGGaGaaeiiaiaabccacaqGGaGaae% iiaiaabccacaqGTaGaaeylaiaabccacaqGGaGaaeiiaiaabccacaqG% GaGaaeiiaiaabccacaqGGaGaaeylaiaab2cacaqGGaGaaeiiaiaabc% cacaqGGaGaaeiiaiaabccacaqGGaGaaeiiaiaabccacaqGTaGaaeyl% aiaabccaaeaacaqGtbGaaeyDaiaabccacaqGGaGaaeiiaiaabccaca% qGGaGaaeiiaiaabccacaqGGaGaaeiiaiaabccacaqGRaGaae4kaiaa% bccacaqGGaGaaeiiaiaabccacaqGGaGaaeiiaiaabccacaqGRaGaae% 4kaiaabccacaqGGaGaaeiiaiaabccacaqGGaGaaeiiaiaabUcacaqG% RaGaaeiiaiaabccacaqGGaGaaeiiaiaabccacaqGGaGaaeiiaiaab2% cacaqGTaGaaeiiaiaabccacaqGGaGaaeiiaiaabccacaqGGaGaaeii% aiaabccacaqGTaGaaeylaiaabccacaqGGaGaaeiiaiaabccacaqGGa% GaaeiiaiaabccacaqGGaGaaeylaiaab2cacaqGGaGaaeiiaiaabcca% caqGGaGaaeiiaiaabccacaqGGaGaaeiiaiaabccacaqGTaGaaeylaa% qaaiaabAfacaqGSbGaaeiiaiaabccacaqGGaGaaeiiaiaabccacaqG% GaGaaeiiaiaabccacaqGGaGaaeiiaiaabUcacaqGRaGaaeiiaiaabc% cacaqGGaGaaeiiaiaabccacaqGGaGaaeiiaiaabUcacaqGRaGaaeii% aiaabccacaqGGaGaaeiiaiaabccacaqGGaGaaeylaiaab2cacaqGGa% GaaeiiaiaabccacaqGGaGaaeiiaiaabccacaqGGaGaaeiiaiaabUca% caqGRaGaaeiiaiaabccacaqGGaGaaeiiaiaabccacaqGGaGaaeiiai% aab2cacaqGTaGaaeiiaiaabccacaqGGaGaaeiiaiaabccacaqGGaGa% aeiiaiaabccacaqGTaGaaeylaiaabccacaqGGaGaaeiiaiaabccaca% qGGaGaaeiiaiaabccacaqGGaGaaeiiaiaab2cacaqGTaaabaGaaeOs% aiaabwhacaqGGaGaaeiiaiaabccacaqGGaGaaeiiaiaabccacaqGGa% GaaeiiaiaabccacaqGGaGaae4kaiaabUcacaqGGaGaaeiiaiaabcca% caqGGaGaaeiiaiaabccacaqGGaGaae4kaiaabUcacaqGGaGaaeiiai% aabccacaqGGaGaaeiiaiaabccacaqGRaGaae4kaiaabccacaqGGaGa% aeiiaiaabccacaqGGaGaaeiiaiaabccacaqGRaGaae4kaiaabccaca% qGGaGaaeiiaiaabccacaqGGaGaaeiiaiaabccacaqGRaGaae4kaiaa% bccacaqGGaGaaeiiaiaabccacaqGGaGaaeiiaiaab2cacaqGTaGaae% iiaiaabccacaqGGaGaaeiiaiaabccacaqGGaGaaeiiaiaabccacaqG% GaGaaeylaiaab2caaeaacaqGwbGaaeyyaiaabccacaqGGaGaaeiiai% aabccacaqGGaGaaeiiaiaabccacaqGGaGaaeiiaiaabUcacaqGRaGa% aeiiaiaabccacaqGGaGaaeiiaiaabccacaqGGaGaaeiiaiaabUcaca% qGRaGaaeiiaiaabccacaqGGaGaaeiiaiaabccacaqGGaGaae4kaiaa% bUcacaqGGaGaaeiiaiaabccacaqGGaGaaeiiaiaabccacaqGGaGaae% 4kaiaabUcacaqGGaGaaeiiaiaabccacaqGGaGaaeiiaiaabccacaqG% GaGaaeylaiaab2cacaqGGaGaaeiiaiaabccacaqGGaGaaeiiaiaabc% cacaqGGaGaae4kaiaabUcacaqGGaGaaeiiaiaabccacaqGGaGaaeii% aiaabccacaqGGaGaaeiiaiaabUcacaqGRaaaaaa!1BBA!\[\begin{gathered} {\text{L94 - - - - - - - - - - - - - - }} \hfill \\ {\text{Su + + + + + + - - - - - - - - }} \hfill \\ {\text{Vl + + + + - - + + - - - - - - }} \hfill \\ {\text{Ju + + + + + + + + + + - - - - }} \hfill \\ {\text{Va + + + + + + + + - - + + + + }} \hfill \\ \end{gathered} \]The genes are supposed to act additively (intermediate inheritance) with the exception of one locus (the 6th or 7th locus) which shows dominance for the shorter LP (for the-alleles). The effect of this locus on LP seems considerably larger than that of the other loci. There are indications of physiological barriers, which means that LP's shorter than the one of L94 or much longer than that of Va are not possible.The effect of + genes in genotypes governing LP's close to these barriers (with very few or very many + alleles respectively) is smaller than in genotypes governing intermediate LP's.     

大麦对盐碱性防护林地改良效果分析

通过盐碱性防护林地播种大麦的试验,结果表明:夏季高温干旱"返盐碱"期间,防护林地播种大麦,其土表(0～20cm)层可溶性盐分和pH值分别比未实施播种大麦的平均降低0.9 g·kg-1和0.4;有机质、水解氮、有效磷和速效钾的平均含量分别比未实施播种大麦的增加5.4 g·kg-1、106.6 mg·kg-1、15.1 m...