ALBERT

Notes: Summary We investigated the abundance of bacteria and fungi on roots of different barley varieties grown in soil and in a nutrient solution. Measurements were made on the rhizoplane and, for soil-grown plants, also in the rhizosphere soil. Further, the influence of plant age was investigated. Barley variety, had a significant influence both for plants grown in soil and in the nutrient solution, and the effects were most pronounced on the rhizoplane. There were no significant differences among varieties in fungal hyphal lengths on the roots. Bacterial abundance on the rhizoplane was significantly decreased with increasing plant age. Varietal differences were maintained over different plant ages.

Notes: Abstract Fertilizer N balance on malting barley (Hordeum vulgare L. cv. Parwan) subjected to a factorial combination of three irrigation (rainfed, irrigated at 45 mm deficit, or irrigated at 85 mm deficit) and three15N fertilizer treatments (2.8, 4.5 and 9.1 g N m−2) was investigated. The crop was grown on a heavy clay soil in the Goulburn-Murray Irrigation Region of south-eastern Australia. Increasing the N application at sowing from 2.8 to 9.1 g N m−2, increased the accumulation of fertilizer N in barley grain from 0.36 to 2.0 g N m−2. Soil N was the major source of N in the grain and plant. Nitrogen uptake was not affected by the irrigation treatment or the application of N fertilizer. Nitrogen content of the grain was 1.57, 1.53 and 1.66% for crops receiving 2.8, 4.5 and 9.1 g N m−2 of fertilizer N at sowing, respectively. Nitrogen harvest index was unaffected by irrigation and fertilizer N application and averaged 81% (range 78–82%) for all crops. Accumulation of fertilizer N in the plant was higher under rainfed conditions (range 20–31%) compared with the 11 to 27% under irrigated conditions. Residual fertilizer in the soil, including that in roots, ranged from 56 to 35%, and was decreased by irrigation. Total15N recovery in the plant plus soil for the 3 rates of N application ranged from 75 to 85% under rainfed conditions and from 54 to 73% under irrigated conditions. There was no difference in the total recovery between the two irrigation treatments. Fertilizer movement to depth was limited and less than 5% of the15N applied at sowing was recovered below a depth of 0.2 m. The small15N accumulation at this depth and the lack of influence of irrigation on the distribution of residual N suggest that loss of N by leaching is minor on irrigated red-brown earths.

Notes: Summary We propose that research be increased on chemical restoration of fertility to the genetic male steriles of barley. Seed harvested from male-sterile plants restored to fertility can then be planted as the female for hybrid barley production. Male fertility has been resotred in male-sterile or gynoecious plants by chemicals in many species, but a satisfactory method has not been developed in barley. Male-sterile mutants that self and mutant-chemical combinations with fertility persisting into the second generation should be avoided.

Notes: Summary The effects of N fertilizer, irrigation and location on genotypic and environmental variances of barley and wheat varieties were studied in a series of trials. Genotypic variance for crude protein content, as well as for grain yield, tended to be higher under high N fertilizer rate (80 kg N/ha). The effect of N fertilizer rate on environmental variance varied with variety and location. Increase in crude protein content resulted in decrease in environmental variance for only a few of the varieties tested. The effect of quantity of irrigation water on genotypic and environmental variance for crude protein content was small.

Notes: 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.

Notes: Summary The growth and yield of seven wheat and two barley cultivars or lines, previously found to show different degrees of boron tolerance under field conditions, were compared in a pot experiment at a range of soil boron treatments. Soil treatments ranged up to 150 mg/kg applied B. Extractable B in soils ranged up to 103 mg/kg. At the highest B treatment seedling emergence was delayed, but the percentage emergence was not reduced. The degree of boron toxicity symptom expression varied between the wheat cultivars and lines, with the two most tolerant, Halberd and (Wq*KP)*WmH)/6/12, displaying the least symptoms. The concentration of boron applied to the soil which produced a significant depression of growth and yield varied between cultivars. For example, the yield of (Wq*KP)*WmH)/6/12 was not affected at the 100 mg/kg applied boron treatment, while the grain yield for (Wl*MMC)/W1/10 was significantly reduced at the 25 mg/kg treatment. There was a linear increase in boron concentration in tillers at the boot-stage with increasing concentration of boron in the soil. The most boron tolerant genotypes had the lowest tissue boron concentrations in each of the treatments. Halberd and (Wq*KP)*WmH)/6/12 had approximately half the boron concentrations of the more sensitive genotypes at the 25 and 50 mg/kg treatments. Differential tolerance of boron within the tissue was also observed. Both Stirling and (Wl*MMC)/W1/10 had significantly reduced total dry matter and grain yields at the 25 mg/kg treatment, while the concentrations of boron in boot stage tillers at this treatment were 118 and 100 mg/kg, respectively. On the other hand, Halberd and (Wq*KP)*WmH)/6/12 had tissue boron concentrations of 144 and 131 mg/kg, respectively, at the 50 mg/kg treatment but yield was unaffected. The relative responses in the pot experiment, for wheat, were in close agreement with field results. Halberd and (Wq*KP)*WmH)/6/12 had the highest grain yields, with the lowest concentrations of boron in the grain when grown under high boron conditions in the field. In pots these two genotypes proved to be the most tolerant of boron. For barley the advantage in grain yield in the field, expressed by WI-2584 compared with Stirling, was not repeated in pots. WI-2584 was, however, more tolerant than Stirling on the basis of total dry matter production. The results show that useful variation in boron tolerance exists among wheat, and that breeding should be able to provide cultivars tolerant to high levels of boron.

Notes: Summary Eight spring barley cultivars, respresenting the known range in partial or slow rusting resistance to leaf rust, Puccinia hordei, were investigated for their effects on the components of partial resistance; infection frequency, latent period, infectious period and spore production per uredosorus per day. Considerable variation was observed among the cultivars for each of the components. The cultivar effects on the components tend to be associated. Cultivar L94 for instance, shows the highest infection frequency, the shortest latent period and a long infectious period. Julia and Vada both have a low infection frequency, a long latent period and a low spore production per sorus per day. This association, though, is only a partial one. The total spore production per unit leaf area (the combined result of the four components) appeared highly correlated with the partial resistance in the field (r=0.85). Only a relatively small portion of the variation in partial resistance cannot be explained by the four components studied. Several other aspects, which might affect the rate of epidemic development, are discussed. Latent period, measuring the onset of the new spore production, estimated partial resistance as well as total spore production did (r=−0.85). In order to evaluate the partial resistance of barley genotypes in the greenhouse the latent period is preferred above total spore production as it is measured more easily, more accurately and sooner after inoculation.

Notes: Summary The use of ethrel for hand crossing in recurrent selection programs with barley is advocated.

Notes: 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, 101/2, 101/2, 13 and 151/2 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.

Notes: Summary Two spring barley composites, one based on eight West-European two-rowed cultivars (A) and one, the predominantly six-rowed composite XXI, based on several thousands of barley cultivars (B), formed the starting point of a recurrent selection procedure. The aim was to study whether recurrent selection in early generations is an effective procedure to improve barley populations for agronomic characteristics, especially grain yield. After two cycles of recurrent selection in the two populations A and B separately, and consisting of single plant selection followed by line selection, one cycle of recurrent selection was applied to the population produced by intercrossing the selected A and selected B lines. The selection for grain yield in the F2 single plant stages and the F3 line stages was carried out by selecting the plants or lines with the largest mean head weight provided that they did not tiller too poorly. Also some selection was applied against extremes in heading date and against tall plants. After two cycles of recurrent selection the grain yield, tested over two years and two locations, had increased with 16.5% in population A and with 27.0% in population B. Both the single plant selection and the line selection had contributed significantly to this response. The population created by crossing the selected A with the selected B lines showed a significant reduction in yield compared to the mean yield of the A and B lines constituting this population. Single plant selection, followed by line selection did raise the yield level 5.7% above that of the mean of these A and B lines. Several lines produced from this intercross combined an excellent grain yield with outstanding resistance to barley leaf rust and powdery mildew. However, these lines like the entire intercross population suffered from susceptibility to lodging, a characteristic derived from population B. In five experimental situations mixtures of genotypes were compared with the mean of the monocultures of the constituting genotypes. The mixture yielded always more, the average mixture effect being 4.5%.

Notes: Summary Lines derived from three cross populations of spring barley were used to investigate whether grain yield can be improved by selection for earliness and number of ears/m2. Time of booting was considered to be indicative for earliness. Selection for early versus late booting was successful in all three populations. Selection for high and low numbers of ears/m2 was successful in only two populations. However, the effects of selection for these traits on grain yield were insignificant.

Notes: Summary Several experiments have been performed in order to induce cell proliferation and plant differentiation from pollen grains by anther culture in barley. Some modifications of the culture media, pretreatments and transfer of the anthers increased notably the frequency of cell division, but the low proportion of normal green plantlets differentiating from microspores and calluses remains the major obstacle preventing the practical use of anther culture in barley breeding.

Notes: Summary Single plants of 12 barley (Hordeum vulgare L. and H. distichum L.) cultivars were randomized to form simulated segregating (mixed) rows. There were 16 mixed rows 15 cm apart, each row containing 24 plants 5 cm apart. In addition, every third row was a control row of one of the cultivars, Bonanza. Each plant was harvested separately. The cultivars differed significantly for all seven characters measured. These seven characters fell into 3 performance groups. Group I characters, seeds/head, 1000 kernel weight, days to ripe and height, showed a higher variance in the mixed rows than in the control rows, had high average heritabilities, and were consistent in performance from one row to another when measured by correlation amongst the cultivars. In Group II, yield/plant and seeds/plant, variance, heritabilities and performance consistency were all low or non-significant. Group III, heads/plant, fell between Groups I and II. These results suggested that single plants with the desired genotype could be successfully selected for characters in Group I only. The frequency with which the most desirable genotype would actually have been chosen with 12.5% selection intensity generally confirmed the above conclusions but indicated that the degree of differences among genotypes was also important in selecting the most desirable genotypes.

Notes: Summary Four cultures of Puccinia hordei isolated from the alternate Ornithogalum hosts in Israel were virulent on seedlings of barley cultivars carrying resistance genes Pa, Pa2, Pa2 + Pa5, Pa2 + Pa6, Pa3, Pa4, and Pa7. Cultures with such a spectrum of virulence have never been reported. The cultures remained stable through 20 successive inoculation and isolation cycles. One of the cultures, T-40SS, retained its specific virulence after selfing on the alternate host. The evolution of virulent races of obligate parasites in the centers of origin of their hosts is discussed.

Notes: Summary Two spring barley composites, one based on eight West-European two-rowed cultivars (A) and the other, the predominantly six-rowed composite XXI, based on several thousands of barley cultivars (B), formed the starting point of a recurrent selection procedure. The aim was to study how effective a repeated process of mild selection against susceptibility followed by recombination of the remaining material was in accumulating partial resistance in four host-pathogen situations. i) Only partial resistance is present and the pathogen population is defined (a given race). ii) Partial and major gene resistance both occur and the pathogen population is defined. iii) Only partial resistance is present and the pathogen population is not defined; a mixture of races that varies over the years. iv) Partial and major gene resistance are both present and the pathogen population is not defined. The variation in partial resistance to barley leaf rust was large in both populations. Population A carried no effective major resistance genes, population B possibly a few at low frequency. The variation in partial resistance to powdery mildew was moderate in A and possibly large in B. As far as effective major resistance genes is concerned A did not carry any, although some recombinations of defeated genes might have been partially effective, while B seemed to carry many. During the selection procedure the populations were always exposed to race 1-2-1 of barley leaf rust and to the mixture of powdery mildew races that was naturally present. The selection procedure consisted of three cycles of recurrent selection. In the initial heterogeneous populations (S0) single plant selection was applied followed by line selection the next year. In both populations 12 lines were selected that were intercrossed in all directions within the two populations. Again single plant (S3) and line selection were exercised and 12 lines selected. The 12 A-lines were intercrossed in all directions with the 12 B-lines and the recombined population again exposed to single plant (S6) and line selection (S7). The selection in this population was done within two-rowed entries (A*) and within six-rowed entries (B*). The selection pressure was mild. In each selection stage about 30% plants or lines most affected by barley leaf rust and some 30% plants or lines most affected by powdery mildew were removed. Among the remaining plants or lines (ca. 45%) a selection for other useful agronomic characteristics was applied. The response to selection was measured in four evaluation trials. Both single plant and line selection contributed to the progress in resistance in both populations to both pathogens. The gain in partial resistance to barley leaf rust was the same in the two populations. The average amount of sporulating leaf tissue in the S7 was about twenty times less than that in the S0. The best S7 lines showed a sixty fold decrease compared with the S0. Corrected for the levelling effect of interplot interference, very strong with barley leaf rust, these gains become 300-and 900-fold respectively. This is comparable with a gain from a very susceptible cultivar to one which is resistant enough to prevent any significant damage in Western-Europe, even in barley leaf rust conducive years. The gain in resistance to powdery mildew from S0 to S7 was far less, being only fourfold and, after correcting for the interplot interference effects in the order of ten- to thirtyfold. The A population contributed more to this gain than the B population, despite its smaller genetic variation. This was caused by the very small response to selection in the B-population in the first two cycles of recurrent selection. The data clearly indicate that recurrent mild selection against susceptibility is a powerful method to accumulate partial resistance. This occurred most efficiently when no confounding major, race-specific resistance genes were present and when a defined pathogen population was used. Little progress was obtained when the host population contained major race-specific resistance genes and was exposed to a racial mixture.

Notes: 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.

Notes: Abstract Achievements and limitations regarding three aspects of cytogenetic research in barley and common wheat are illustrated and discussed. Unambiguous chromosome identification has become possible through the application of chromosome banding techniques, mainly C-banding, N-banding and Ag-banding. Gene localisation studies have yielded a vast amount of information regarding the genetic architecture of barley and wheat. Many genes have been allocated to specific chromosomes, and linkage studies have been carried out with some of these genes. There is growing evidence for a considerable discrepancy between distances on the genetic linkage maps and the physical maps of barley and wheat chromosomes. Although barley can be hybridised with most species of the genus Hordeum and with several species of related genera, interspecific gene transfer is very rare and barley breeding can presently make use of the gene pool of only one wild species, viz. H. vulgare ssp. spontaneum. For wheat breeding, the gene pools of species of the genus Triticum and species of related genera are accessible. Several methods have been developed to achieve gene transfer. Genome interactions in interspecific hybrids result in spatial separation of the parental genomes, in nucleolar competition, and sometimes in chromosome elimination and the formation of haploids.

Notes: Summary The genetic relationships between three known genes for resistance to Puccinia hordei in barley, Pa 3, Pa5 and Pa 7, were re-examined because of conflicting reports in the literature. PA 3 was found to be independent of Pa 5 and Pa 7, but the latter two are linked with an estimated recombination value of 7.6±1.4%. Trisomic analysis confirmed Pa 7 to be on chromosome 3, but Pa 3 could not be associated with chromosomes 3 to 7 and, therefore, is inferred to be either on chromosome 1 or 2