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N. O. Bertholdsson 《Journal of Agronomy and Crop Science》1987,158(4):259-270
The leaf permeability of eighteen field grown oat cultivars was examined with the aid of a viscous-flow porometer. The relationship of leaf permeability to grain yield was determined during two different years. An F4 population and its parents were further studied for frequency distribution of leaf permeability, total plant dry matter, and grain yield. A plus and minus selection based on leaf permeability measurements was also studied.
Leaf permeability proved to be cultivar specific, i.e. a cultivar with low values one year also exhibited low values next year and vice versa (rank correlation r = 0.55, p < 0.05). This in spite of that one year was dry and the other wet. Old cultivars had low leaf permeability while new cultivars and new promising breeding lines had, with one exception, high values. Leaf permeability was positively correlated with grain yield, particularly during the wet year (r = 0.70, p < 0.001). The population had a population mean of 1.09 porometer units compared to 0.95 and 1.18 porometer units for the parents (LSD = 0.08, p < 0.05). Both total dry matter and grain production were positively correlated (p < 0.001) with leaf permeability during grain-filling. The plus and minus selection for leaf permeability within a population showed in the next generation significantly different population means (0.69 and 0.79 porometer units, LSD = 0.08, p < 0.05). Total dry weight and grain yield were six per cent higher (non significant) in the plus selection than in the minus selection. The possibility to use leaf permeability as a selection criterion is discussed. 相似文献
Leaf permeability proved to be cultivar specific, i.e. a cultivar with low values one year also exhibited low values next year and vice versa (rank correlation r = 0.55, p < 0.05). This in spite of that one year was dry and the other wet. Old cultivars had low leaf permeability while new cultivars and new promising breeding lines had, with one exception, high values. Leaf permeability was positively correlated with grain yield, particularly during the wet year (r = 0.70, p < 0.001). The population had a population mean of 1.09 porometer units compared to 0.95 and 1.18 porometer units for the parents (LSD = 0.08, p < 0.05). Both total dry matter and grain production were positively correlated (p < 0.001) with leaf permeability during grain-filling. The plus and minus selection for leaf permeability within a population showed in the next generation significantly different population means (0.69 and 0.79 porometer units, LSD = 0.08, p < 0.05). Total dry weight and grain yield were six per cent higher (non significant) in the plus selection than in the minus selection. The possibility to use leaf permeability as a selection criterion is discussed. 相似文献
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N. O. Bertholdsson 《Journal of Agronomy and Crop Science》1990,164(1):54-67
The assimilation and translocation pattern of radioactive 14-C-assimilates and how it may affect nitrogen fixation was studied in conventional and semi-leafless pot grown field peas ( Pisum sativum L.). Leaf areas, plant development patterns and yield components and their influence on protein content, protein yield and seed yield were studied by using simple regression, multiple regression and factor analyses over a period of two years of field grown material.
It was shown that roots and nodules received most of the carbon assimilate from the lower leaves at the beginning of flowering. Four weeks later most of the assimilates came from the upper leaves. Furthermore, it was discovered that stipules were more important than leaflets in supplying the roots and nodules. Field studies supported the results obtained in pot grown material. They also showed that in order to achieve high seed and protein yield it is more important to have many generative nodes instead of a few with several pods on each. In semi-leafless types, vegetative upper nodes and late flowering are also important factors. An ideotype suited for both high seed yield, high seed protein yield and high protein content is discussed. 相似文献
It was shown that roots and nodules received most of the carbon assimilate from the lower leaves at the beginning of flowering. Four weeks later most of the assimilates came from the upper leaves. Furthermore, it was discovered that stipules were more important than leaflets in supplying the roots and nodules. Field studies supported the results obtained in pot grown material. They also showed that in order to achieve high seed and protein yield it is more important to have many generative nodes instead of a few with several pods on each. In semi-leafless types, vegetative upper nodes and late flowering are also important factors. An ideotype suited for both high seed yield, high seed protein yield and high protein content is discussed. 相似文献
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The aim of the investigation was to find out if certain North American genotypes of winter wheat with exceptionally high grain protein concentrations (GPCs) are characterized by an extraordinary ability to take up and/or distribute nitrogen from the soil to the grains. Two of these genotypes were grown in a field trial in southern Sweden together with three ‘normal’ Swedish genotypes (two modern cultivars and one old landrace). They were compared with respect to accumulation of dry matter and nitrogen in both grains and straw when cultivated at three levels of N-fertilization (0.75 and 150 kg N ha-1)- The results of this trial demonstrated that the yields of above-ground biomass (BY) and grain (GY) were significantly lower for the American genotypes than for the Swedish ones. Also the nitrogen yields in biomass (NBY) and grain (NGY) were significantly lower in the American types but the difference between the two groups was not so pronounced as with respect to dry matter yields. The American types were thus superior to the Swedish ones in relative ability to take up nitrogen but not in absolute terms. The GPCs of the American wheats were very high also under Swedish growth conditions but a regression analysis of the relation between GPC and GY revealed a very strong negative correlation between these parameters (r = -0.95 at 0 N and r= -0.99 at 150 N). The correlation between GPC and HI was highly negative, too, (r = -0.83 at 0 N and r = 0 89 at 150 N). The specific ability to take up nitrogen was determined by estimating the changes in soluble soil nitrogen (NO3+ NH4) in the unfertilized plots during the vegetation period. These measurements indicated that the American types were less effective in retrieving nitrogen from the soil than the Swedish ones. The analysis of the soil in the fertilized plots also demonstrated that the American types were slightly inferior to the others in their ability to recover externally applied nitrogen. The efficiency to utilize absorbed N for production of above-ground and grain biomass was also estimated from the experimental data. The results demonstrated very clearly that the American genotypes exhibited a considerably lower nitrogen utilization efficiency than the Swedish types. Also the efficiency to allocate absorbed nitrogen into the grains (expressed as nitrogen harvest index, NHI) was examined and was found to be nearly identical for all genotypes and almost independent of the level of N fertilization. It is therefore claimed that the results reported in the present communication confirm the conclusions from part I of this investigation, namely that the main reason for the high GPCs in the American genotypes investigated here are their relatively low dry matter production in the grain filling period. This fact does not exclude, however, that other high-protein genotypes may carry genes which in appropriate crosses can combine high-yielding ability with an improved GPC. 相似文献
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N-O BERTHOLDSSON 《Weed Research》2005,45(2):94-102
The objectives of this study were to identify traits in spring barley (Hordeum vulgare) and spring wheat (Triticum aestivum) related to the competitive ability of the crop and to determine their importance. Weed biomass 1–2 weeks prior to ear emergence was used as a measure of genotypic differences in competitiveness against weeds. Crop trait measurements comprised early crop biomass, early shoot height, straw length, heading and maturity. Early crop biomass 1–2 weeks prior to ear emergence was used as an overall trait for the various characters related to early vigour. In addition to these morphological traits, the potential allelopathic activity of the tested cultivars was determined using an agar-based bioassay with Lolium perenne (ryegrass). In both barley and wheat, multiple regression analysis revealed that early crop biomass and potential allelopathic activity were the only parameters that significantly contributed to competitiveness. In barley, early crop biomass explained 24–57% of the observed genotypic variance across 4 years, allelopathic activity explained 7–58% and combined they explained 44–69% of the observed genotypic variance. In wheat, the corresponding figures were lower: 14–21% for early biomass, 0–21% for allelopathic activity and 27–37% when combined. Model predictions suggested that new cultivars with increased early vigour and allelopathic activity offer a potential to further reduce weed interference. 相似文献
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Ten commercial clones of willow and two breeding clones were studied for their ability to compete with weeds during the establishment year at three different sites in southern Sweden. Cuttings were planted according to commercial practice in April, and the two treatments, ‘Weeded’ and ‘Unweeded’, were laid out in a strip‐plot design. Weeds in the ‘Weeded’ treatment were removed mechanically and by hand hoeing. Willow plant shoot weight and plant mortality were measured after the first growing season to evaluate the initial effect of weeds. In addition, weed flora, weed aboveground biomass, soil properties, shoot damage and soil moisture were assessed during the growing season. Plant mortality was <1% in the ‘Weeded’ treatment at the three study sites, while in ‘Unweeded’ it was significantly higher, 2.7%, 24.6% and 37.4%. Weeds reduced willow plant shoot weight by 93.4%, 94.0% and 96.1% at the three sites. Only one site showed clonal differences in shoot growth reduction, as well as in plant mortality. These results show the importance of weed control in willow plantations, as growth of all clones tested were dramatically hampered by weeds during the first growing season, regardless of trial site conditions. Moreover, conditions at certain sites, such as soil properties in combination with weed cover, may cause high plant mortality during the establishment year in this perennial biomass crop. 相似文献
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N-O BERTHOLDSSON 《Weed Research》2010,50(1):49-57
It is becoming apparent that allelopathy plays a significant role in the competitive ability of cereals against weeds; barley, wheat and rice cultivars with high allelopathic activity have been identified. However, direct breeding efforts to improve allelopathy have to date only been reported in rice. In this study, a breeding programme in spring wheat ( Triticum aestivum ) was evaluated to determine the efficiency of selection of allelopathy and the ability of breeding lines to suppress weeds in the field. The material used originated from a cross between a Swedish cultivar with low allelopathic activity and a Tunisian cultivar with high allelopathic activity. Allelopathic activity was measured as growth inhibition of perennial ryegrass ( Lolium perenne ) roots when grown together with the wheat cultivars on agar. For screening of F2 populations, a single plant bioassay was used for the first time. In the F6 and F7 generations, three breeding lines with an average improved allelopathy of 20% and one line with an unimproved allelopathy activity, but with the same phenotype as the high allelopathic lines, were tested together with the low allelopathic Swedish parent. The main result from the field study was a 19% average reduction of weed biomass for the high allelopathic lines, but no significant reduction of the low allelopathic breeding line. Early shoot length and early crop biomass (stages 37–39, Zadoks scale) and straw length of the high allelopathic lines were not significantly different from the Swedish parent. A negative effect was that grain yield was reduced by 9% in the high allelopathic lines. It is suggested that the reduced biomass of weeds in plots planted with the highly allelopathic wheat lines is related to differences in allelopathic activity and not differences in plant growth. 相似文献
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N-O Bertholdsson 《Weed Research》2004,44(2):78-86
Barley (Hordeum vulgare L.) landraces and cultivars from Finland, Sweden, Denmark and the Baltic states, in total 127, were analysed for allelopathic activity against ryegrass (Lolium perenne L.). The germplasm covered most of the gene pool used during 100 years of barley breeding. An agar‐based bioassay developed for screening allelopathic activity was used. In the germplasm from all countries a decreasing trend in allelopathic activity was observed with the introduction of new cultivars from 14% for the Swedish to 31% for the Finnish cultivars. In the Finnish, Swedish and Baltic cultivars an increase in root growth was noticed, and changes in root biomass therefore cannot explain the decrease in allelopathy. In fact, the allelopathic activity per milligram root decreased with 32–85%. In contrast, root growth decreased over time in the Danish collection. In the Finnish cultivars both two‐ and six‐row barley cultivars were tested with similar results. Allelopathic activity of barley probably originated from different landraces, and in most cases from a specific landrace from the Swedish island of Gotland. We suspect that more than 100 years of selection and breeding have resulted in a dilution of the genes from landraces and consequently a declining allelopathic activity. In the Swedish collection, two cultivars did not follow the general trend and in both cultivars, several landraces had been combined. 相似文献
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N.-O Bertholdsson 《European Journal of Agronomy》1998,9(4):213-222
The objective of the present study was to identify important environmental factors and establish a multi-environment testing regime that promotes genotype×environment interactions in grain protein concentration (GPC) of malting barley (Hordeum vulgare L.). A reference material was used, consisting of 19 spring barley cultivars with known environmental×genotype variability from numerous yield trials performed in different regions of Europe. The GPC data from these trials were used to calculate a GPC stability index (PSI) based on means of standardized GPC variances. The study was performed over 3 years with outdoor soil-beds in five treatments; three nitrogen regimes and one pre- and one post-anthesis water-stress period. The material was grown in randomized, 22-cm-spaced, hill plots with 12 plants per plot and four to eight replicates. When needed, the plots were drip-irrigated. At sowing, a stationary rain shelter was placed over one bed to establish pre-anthesis drought stress, and moved at anthesis to another bed for post-anthesis stress. At maturity, the plots were harvested, and GPCs and yields were analysed. The variance of GPC over treatments was positively correlated with PSI. The correlation coefficient varied from 0.29 to 0.85, depending on the year, number of treatments and number of replicates. The water-stress treatments, followed by the high-nitrogen-fertilizer treatment, contributed most to the correlations observed, whereas the low-nitrogen treatment had little effect. Studies of seedling root and shoot length from plants grown in hydroponics for 2 weeks revealed that GPC stable cultivars, with a few exceptions, had longer seminal roots and higher root/shoot length ratios. Possibilities of screening for low and stable GPC by using hill plots subjected to different nitrogen- and drought-stress regimes are discussed. 相似文献