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1.
Summary Four six-rowed uniculm lines of spring barley were grown in two yield trials at different sowing densities. One trial was grown on light sandy soil in 1990. The second trial was grown on clay soil in 1991 and included the two-rowed, tillering cultivar Golf. In the trial on sandy soil, the grain yield of the uniculm lines approached that of Golf grown in an adjacent trial, but in 1991 when the growing conditions were more favourable, Golf yielded significantly more than the uniculm lines. Uniculm lines apparently perform relatively better under marginal growing conditions than in high yielding environments.The uniculm lines do not conform to the ideotype proposed for wheat by Donald (1968) but the results show that a drastic change in plant type need not to imply a large drop in grain yield. 相似文献
2.
Genetic analysis of powdery-mildew (Erysiphe graminis f.sp. hordei) resistance derived from wild barley (Hordeum vulgare ssp. spontaneum) 总被引：1，自引：0，他引：1
The inheritance of resistance to powdery mildew was investigated in 20 accessions of Hordeum spontaneum and in 20 F4 lines derived from crosses between the variety ‘Aramir’ and 13 accessions of H. spontaneum. Two resistance genes were detected in 17 accessions, and three resistance genes in one accession. In two accessions, only one resistance gene was present. The 20 breeding lines showed a large variation in infection type and infection level. The genetic relationship between the resistance genes detected was investigated in the seven most resistant F4 lines. These F4 lines were divided into three groups which carried different resistance genes. In two lines, the detected resistance gene was shown to be race-specific. 相似文献
3.
Summary Genotypic differences for growth stage dependent expression of partial resistance to barley powdery mildew have been identified on the basis of two components of resistance in the glasshouse and the pattern of epidemic development in the field.Differences for infection frequency and proportion of sporulating colonies were highly significant between the 16 genotypes investigated at four stages of plant development in the glasshouse. Both resistance components were significantly correlated mutually (r=0.73 to 0.86) and with the infection level on leaves developed at comparable growth stages in the field (r=0.52 to 0.73). The infection level of seedlings in the glasshouse was significantly correlated with the infection level of the leaves of the first until the third node in the field (r=0.70 to 0.73). Adult plant resistance was predominantly expressed at the uppermost leaf. A clear genotype × growth stage interaction was apparent for infection level; some genotypes showed partial resistance predominantly at the seedling stage and others predominantly at the adult plant stage.Abbreviations IF
Infection Frequency, number of colonies per cm2 leaf area, glasshouse experiment
- IL
Infection Level, number of colonies per cm2 leaf area, field experiment
- PSC
Proportion Sporulating Colonies from total number of colonies, glasshouse experiment 相似文献
4.
Feberwee A Dijkstra JR von Banniseht-Wysmuller TE Gielkens AL Wagenaar JA 《Veterinary microbiology》2005,111(1-2):125-131
Mycoplasma gallisepticum (MG) and M. synoviae (MS) are the cause of considerable economic losses in the poultry industry. Molecular differentiation of avian Mycoplasma strains may be helpful in tracing infections and in the evaluation of implemented intervention strategies. Amplified Fragment Length Polymorphism (AFLP) has shown to be a powerful typing technique but the application for poultry Mycoplasma strains is very limited. The aim of this study was to evaluate the reproducibility and discriminatory power of AFLP HindIII/HhaI and AFLP BglII/Mfel for the inter- and intraspecies differentiation of avian mycoplasmas and to compare these test characteristics with digitalized Random Amplified Polymorphic DNA (RAPD) analysis. The reproducibility of RAPD, AFLP HindIII/HhaI and AFLP BglII/Mfel was 50-100, 97-98 and 86-99%, respectively. RAPD and both AFLP enzyme combinations were able to differentiate between five avian Mycoplasma species. For AFLP, five MG and four MS clusters could be identified. The phylogenetic tree for both enzyme combinations was comparable. For RAPD, four MG clusters could be identified. For MS, however, due to the poor reproducibility of the RAPD technique, no clear genogroups could be identified. On basis of the results of this study it can be concluded that AFLP is a powerful technique for the genotyping of avian mycoplasmas and that, although AFLP HindIII/HhaI generated patterns with less fragments, the final results showed homologous results. 相似文献
5.
Casparus J. BRINK Anneke POSTMA Etienne SLABBERT Ferdinand POSTMA A. Muthama MUASYA Karin JACOBS 《土壤圈》2020,30(6):778-790
Aspalathus linearis is a commercially important plant species endemic to the Cape Floristic Region of South Africa and is used to produce a herbal tea known as rooibos tea. Symbiotic interactions between A. linearis and soil bacteria play an important role in the survival of Aspalathus plants in the highly nutrient-poor, acidic fynbos soil. The aim of this study was to characterize and compare rhizosphere and bulk soil bacterial communities associated with natural and commercially grown A. linearis, as well as the effect of seasonal changes on these communities. Bacterial communities were characterized using high throughput amplicon sequencing, and their correlations with soil chemical properties were investigated. The N-fixing bacterial community was characterized using terminal restriction fragment length polymorphism and real time quantitative polymerase chain reaction. Actinobacteria, Proteobacteria, and Acidobacteria were the most dominant bacterial phyla detected in this study. Highly similar bacterial communities were associated with natural and commercially grown plants. Significant differences in the bacterial community were observed between rhizosphere and bulk soils collected in the dry season, while no significant differences were detected in the wet season. This study provides insights into bacterial community structure and potential factors shaping bacterial community structure with commercially important A. linearis. 相似文献
6.
A. G. Balkema-Boomstra 《Euphytica》1992,65(2):99-106
Summary The objective of this study was to evaluate traits which can facilitate and improve selection for grain yield of spring barley. Five experiments were conducted in different environments to measure grain yield and yield related traits of breeding lines and exotic varieties. Differences for rate of canopy expansion were significant and offer the opportunity to select for a high weed suppressing potential but there was no relation to grain yield. Dry matter yield/m2 at anthesis and its water-soluble-carbohydrate content were not correlated with grain yield/m2 and number of grains/m2. Variation in biomass among breeding lines with a similar development and plant height was small. Biomass standardized for plant height was stable across environments and showed a good correlation with number of grains and grain yield. The contribution of pre-anthesis assimilation to grain yield was only important under low yielding experimental conditions, but the differences among the genotypes for this trait were inconsistent. It may be difficult to select genotypes with a high potential contribution of pre-anthesis assimilation to grain yield. 相似文献
7.
Sri Rejeki Adolphe O. Debrot Anneke M. van den Brink Restiana W. Ariyati Lestari Lakshmi Widowati 《Aquaculture Research》2021,52(1):373-380
The effectiveness of green mussel (Perna viridis) cultivation was compared between longline culture and the traditional bamboo stake method using different mussel densities in a rural area on the north coast of Java, Indonesia. The study took place in a rural area about 2 km north‐east from the city of Semarang where unsustainable shrimp and fish pond culture in the past has led to massive mangrove loss, spiralling environmental degradation and socio‐economic disintegration. Mangrove‐friendly alternatives for a sustainable socio‐economic recovery of local livelihoods are urgently being sought. Longlines were more successful than the stake method in spat collection. Longlines also showed a small but significantly higher relative weight gain and specific growth rate for mussels than bamboo stakes. Mussels in lower densities showed higher survival and grew to larger individual sizes, but initial seeding density had no significant effect on relative weight gain or specific growth rate per stocking. Slightly lower set‐up costs and time investment and somewhat higher yields for longlines give an almost twofold higher income per time unit of own time invested by the farmer for longline culture over the traditional stake culture method. The profitability of mussel culture using the stake method is below the average hourly wage for skilled labour, but above that when using the longline method. We conclude that green mussel culture using the longline system is feasible as an alternative to less sustainable forms of livelihood for the local communities in mangrove areas. 相似文献
8.
The inheritance of the powdery mildew resistance of eleven primitive barley varieties was investigated. crosses with varieties with identified resistance genes revealed that at least three different genes are present in a group of six genotypes from Greece (Hor736, Hor847, Hor878, Hor1159, Hor1379 and Hor1873) and one from Turkey (Hor1188). One dominant gene is common to these seve genotypes and in the Greek accessions a second gene is present. The expression of this second gene was respectively dominant in the crosses with Hor736 and Hor1159, recessive in the crosses with Hor878 and Hor1873, and depended on the employed powdery mildew isolate in the crosses with Hor847 and Hor1379. The detected genes differ from the resistance genes of the crossing partners, viz. Ml-al2, Ml-(Ab), Ml-(CP) and Ml-(1402). The accessions from China (Hor824 and Hor4021) each possess two resistance genes which differ from Ml-a12, Ml-(La) and Ml-(CP). The major gene is common to both accessions and is either identical, allelic or closely linked to a gene in the variety Nigrate. The Columbian accession Hor1894 possesses one resistance gene linked to a resistance gene in Nigrate but this gene differs from the Ml-a locus. The variety Palestine (Hor3997) possesses two resistance genes of which one is allelic or closely linked to Ml-(at). 相似文献
9.
The effect of powdery mildew on the photosynthesis and grain yield of partially resistant spring barley was investigated. The effect of powdery mildew on the CO2 exchange rate (CER) of inoculated and non-inoculated leaves was measured in several glasshouse experiments. Grain yield reduction by powdery mildew was determined in three field experiments. The CER of the inoculated leaves was reduced by infection but that of the non-inoculated leaves was not significantly different from that of the corresponding leaves of the control plants. The reduction in CER of the different genotypes was closely related to the percentage leaf area infected with powdery mildew. The correlation between degree of mildew infection and grain yield reduction varied between r = 0.84 (significant at P = 0.01) and r = 0.41 (not significant). Differences in greenness of the crop were correlated better with grain yield reduction (r = 0.66, P = 0.01) than powdery-mildew infection itself. Low percentages of powdery-mildew infection did not lead to significant reduction in grain yield. Partial resistance to powdery mildew could thus be a valuable attribute of future barley varieties. 相似文献
10.
Resistance to western flower thrips in greenhouse cucumber: effect of leaf position and plant age on thrips reproduction 总被引：1，自引：0，他引：1
Willem Jan de Kogel Anneke Balkema-Boomstra Marieke van der Hoek Sierd Zijlstra Chris Mollema 《Euphytica》1997,94(1):63-67
Three greenhouse cucumber (Cucumis sativus L.) accessions, previously selected for low levels of damage after infestation
with Frankliniella occidentalis (Pergande), were tested for resistance against F. occidentalis in a no-choice greenhouse experiment
at the mature plant stage. The three accessions showed a strong reduction in thrips damage compared to the susceptible control.
The effects of leaf position and plant age of the four cucumber accessions on the reproduction of F. occidentalis were determined
in a leaf disc assay. Leaf position had a significant effect on thrips reproduction, whereas plant age, within the test range,
had not. In general, reproduction was higher on young leaves. Reproduction as measured on leaf discs from certain leaf positions
was strongly correlated with resistance of mature plants in the greenhouse, and can therefore be used as a quick test to screen
cucumber accessions for resistance against thrips.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献