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1.
Herbage yield trials are necessary to test if candidate varieties are well suited for organic conditions. In order to elucidate
a particular suitability for organic conditions, we run such trials in parallel under both organic and conventional conditions.
Here, we report on second and third year results of the sowings 2004 and 2005. These trials are part of a targeted breeding
programme for organic conditions. Irregular colonisation of pure grass plots with adventitious plants, in particular white
clover, was recognized as a major constraint to the quality of the results obtained under organic conditions. The coefficients
of variance in dry matter yield almost doubled when compared to conventional trials, and significant differences in annual
yield among varieties were rare. However, when herbage yield was corrected for the estimated fraction of adventitious plant
colonization at each cut, the number of instances with statistically significant differences for annual yield among varieties
increased more than fourfold. Dry matter yields under organic and conventional conditions were significantly and positively
correlated. However, analysis of variance showed a significant culture type by variety interaction for annual dry matter yield
in 12 out of 24 trials. When diploid and tetraploid varieties of the same Lolium species were tested in one common trial, only tetraploid varieties were identified as being particularly well suited for organic
conditions, while in these trials, the great majority of apparently poorly suited varieties were diploid. This suggests that
breeding tetraploid Lolium varieties is promising when aiming at a favourable response to organic agriculture. 相似文献
2.
Summary Effects of moving mean covariance adjustments on error control, genetic variance component estimates and selection were examined in nine trails in peanut breeding nurseries. Neighbourhood sizes of two to fourteen adjacent plots were used in two types of moving mean covariates: one based on adjacent plot yields and a second based on adjacent plot residuals after removal of replicate and treatment effects. Both covariate types reduced error variance, in one trial by up to 57%, although the covariate type giving the most error reduction varied among trials. Generally most error variance reduction occurred when six to eight adjacent plots were used.In some trials genetic variance component estimates following covariance adjustment were higher than those from unadjusted analyses and in other trials they were lower. As the neighbourhood size included in the moving mean increased from two to fourteen plots the genetic variance component estimate changed considerably in some trials. However, large rank changes did not appear to be associated with these genetic variance component changes as neighbourhood size had little influence on the selection of progenies. Also, genetic effects included in the yield covariate had little influence on selection of elite lines as essentially the same lines were chosen or rejected when residual covariates lacking these genetic effects wre used. 相似文献
3.
Summary Ten inbred lines from the open-pollinated maize variety Jarvis were selected from 51 randomly collected lines to represent a wide range of susceptibility to one isolate each of Bipolaris maydis or Colletotrichum graminicola. Ten isolates of each pathogen were selected for a range of virulence on a maize line with average resistance. Resistance and virulence ratings were based on lengths of lesions that developed on leaves of greenhouse-grown seedlings inoculated with 5 l droplets of suspensions of known spore concentrations. For each disease the ten maize lines were inoculated in all possible combinations with the ten pathogen isolates. The experiment was run six times with each pathogen. Analysis of variance for individual trials indicated a significant interaction between maize lines and B. maydis isolates in all six trials and between maize lines and C. graminicola isolates in four of six trials. For both diseases. the combined analysis over all six trials revealed no significant interaction. Apparently the expression of specificity in these host-pathogen interactions is variable. 相似文献
4.
Effects of the logarithmic and site mean transformations on the relative yields from a variety trial
D. G. Pederson 《Euphytica》1986,35(1):169-174
Summary Two transformations commonly used in the analysis of multilocation variety trials are the logarithmic transformation and the site mean transformation, in which each observation at a site is divided by the site mean yield prior to analysis. Expressions are derived for differences between the yields of varieties after each of these transformations, in terms of the original yields. Similar expressions are also determined for the regression mean method of estimation, which is based on linear regressions of variety means on site means. It is shown that the two transformations produce almost identical analyses of variance, and that relative yields are very similar on the three scales of measurement provided that the harmonic mean of site means is used as the predictor value in the regression method. 相似文献
5.
A. A. Rosielle 《Euphytica》1980,29(1):129-133
Summary Efficiencies of lattice designs, check plot designs, and moving means were compared in seven environments for control of error in wheat breeding trials. Lattice analyses of lattice designs and check plot covariance analyses of check plot designs gave similar CV's and intra-site heritabilities and were superior to direct RCBD analyses of these designs. Moving mean covariance analyses were generally only slightly less efficient than lattice analyses or check plot covariance analyses. Differences between designs and methods of analysis, which were evident on an intra-site basis, were not evident from combined analyses indicating that genotype x environment interaction is much more important than intra-site error in limiting progress from selection. Moving mean covariance analyses with 2 replicates per location and as many locations as feasible is suggested as a useful strategy for early generation wheat breeding trials. 相似文献
6.
R. A. Whitehead 《Euphytica》1968,17(1):81-101
Summary Selection and breeding is likely to provide the only answer to Lethal Yellowing disease of coconuts. The present review outlines the short term and long term programmes started in Jamaica and gives details of the exploitation of local varieties and the assembly of genotypes for further work.In the short term programme the botanical and economic characteristics of Malayan Dwarf coconuts have been studied, seed quality has been improved and a gradual change over from the disease susceptible Jamaica Tall variety to the Malayan Dwarf is now taking place. Over a three year period proportionately fewer San Blas than Jamaica Tall palms have died in disease affected areas where both are growing together, and it is considered that the San Blas variety merits further detailed study.The long term programme is mainly concerned with attempts to improve the Malayan Dwarf by hybridisation and to establish whether or not these and other hybrids are resistant to Lethal Yellowing. In addition, a wide range of genotypes from the major producing areas in the world has been introduced and established in field trials, in an attempt to find further sources of disease resistance.Though useful results have already been obtained, in field tests relying on natural spread of the disease, progress would be more rapid if the disease could be transmitted at will.Joint Coconut Research Scheme, Yandina, British Solomon Islands Protectorate 相似文献
7.
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.This work has been carried out under Research Contract No. 1037/GS with the International Atomic Energy Agency. 相似文献
8.
Genotypic, environmental and genotype by environmental variability of 30 different crops was evaluated by estimating variance components from trial series in 16 years. Yield data from official German variety trials for cultivation and use (VCU) were analysed over the period from 1991 to 2006. The natural dominant part was pure environmental variation. Genotype, genotype by environment and plot error are smaller and of the same magnitude. Interaction of genotypes with locations is larger than with years. Compared with variance component estimates of crops from a study involving 16 crops from former West German VCU trials between 1975 and 1986 overall variability of yielding performance was lower in the recent study for all components except for location. Precision of variety comparisons over locations and years is higher in recent VCU trial systems when assuming equal dimensioning of testing resources. Lower values for genotype by environmental variances, especially for the genotype by year component lead to lower standard errors for variety comparisons. 相似文献
9.
Summary The possibility of combining anew the genomes of wild and cultivated progenitors of triploid S. x juzepczukii and pentaploid S. x curtilobum by following the known evolutionary pathway of these species was investigated.The resynthesis of S. x juzepczukii was easy, and a wide range of synthetic forms was bred. Among these were forms with higher frost resistance (-5°C) than has been found in natural S. x juzepczukii. The total tuber glycoalkaloid content of several synthetic hybrids was lower than or as low as that of natural clones. Most synthetic hybrids were more vigorous than natural S. x juzepczukii and produced about the same types of tubers as are found in the natural range of variation. The best diploid parents were found in the species S. goniocalyx.The attempt to resynthesize pentaploid S. x curtilobum has not been successful but tetraploid plants were obtained in the process. An explanation for the occurrence of tetraploids resulting from triploid x tetraploid and/or diploid crosses is offered.The newly bred tetraploids contain at least one genome from S. acaule (possibly two) and hybridize easily with ssp. andigena. They thus provide a means for the transfer of S. acaule germ plasm into the tetraploid cultivated gene pool which would profit from the frost resistance of S. acaule. 相似文献
10.
Thirteen varieties of Brazilian barley selected for malting qualities were analysed by RAPD (Random Amplified Polymorphic DNA). Amplification with 18 random primers generated 221 reproducible bands, of which 206 bands were polymorphic (93%):of this number, 137 fragments (62%) detected diversity among varieties and 56 bands (25.34%) allowed the distinction of varieties or groups of them. Variation was detected in all Brazilian varieties studied. Within-variety similarities estimated by Jaccard Similarity Coefficient ranged from 0.28 to 0.94, with averages ranging from 0.57 to 0.83, and an overall average of 0.72. Nevertheless, in the cluster analysis representatives of the same variety always fell into the same group and only later joined the other varieties. The average intervarietal similarities estimated by Jaccard Similarity Coefficient ranged from 0.45 to 0.62, with an overall average of 0.52. Many bands or combinations of bands which were responsible for the differentiation of all varieties were detected. Nevertheless, the majority of these bands cannot be considered as diagnostic markers because a great number of them did not occur in many representatives of the variety or had low intensity or even because they were not easily identified in the total pattern of bands. 相似文献
11.
12.
Summary Wide hybridizations between M. arvensis and Brassica amphidiploid species (B. napus and B. juncea) were carried out in order to incorporate desirable traits of M. arvensis into Brassica crops. Crossing barriers between them were present without the use of in vitro techniques. F1 hybrids have been produced through ovary culture, when M. arvensis were used as a female parent. Higher hybrid embryo productivity (3.07 embryos per pollination) was obtained in the cross of M. arvensis x B. napus than in that of M. arvensis x B. juncea (0.79 embryos). The hybridity was confirmed by morphology, cytology, isozyme and Southern analyses. The first backcrossing progenies and open pollinated ones were produced. 相似文献
13.
Summary Forty-two crosses and their reciprocals in maize (Zea mays L.) involving inbred lines highly diverse for protein content were evaluated in four environments. Data were recorded on crude protein content of grain, protein yield, grain yield, 1000 kernel weight, dry matter content of ear at harves,, days to 50% slking, plant height, ear height, and early vigor. No significant variation due to reciprocal differences was observed for protein content and early vigor. For all other traits the variance component due to reciprocal x environment interactions was significant while the variance component due to reciprocal differences was significant only for kernel weight, dry matter content of ear, plant height, and ear height. The variance components due to nuclear differences and their interactions with environments were always highly significant and larger than the components due to reciprocal differences and reciprocal x environment interactions. The instability and low magnitude of reciprocal differences indicated that it might be difficult to exploit them commercially. However, seeing the presence of reciprocal differences for most of the traits studied, the evaluation of breeding materials for these differences seems to be important.The research work was supported by the Deutsche Forschungsgemeinschaft, Sonderforschungsbereich 142. 相似文献
14.
C. M. Tavella 《Euphytica》1978,27(2):577-580
Summary Septoria leaf blotch readings, date of heading and plant height appeared strongly correlated in six variety trials with 25 varieties each. Three trials were conducted in 1972 and three in 1976. The taller and later the cultivars, the lower its Septoria leaf blotch score tended to be. The yields also were less strongly reduced in taller and later cultivars, as calculated from another experiment. 相似文献
15.
基于协方差阵结构优选的作物品种区域试验分析 总被引:1,自引:1,他引:0
论述了线性混合模型方差协方差结构与作物品种区域试验分析模型的对应关系,以我国2005-2006年东北华北玉米8组区域试验资料为例,按照线性混合模型分析原理及模型拟合信息量准则与似然比测验,对区域试验品种方差协方差的结构特性及不同方差协方差结构模型在品种效应估计与评价的差异状况进行了探讨。结果表明,在分析的所有试验中,环境间品种效应方差协方差均不符合方差分析模型假设的同质性结构,而是呈现为各种异质性结构;产量效应测验差异显著的品种对数目在方差分析模型与最佳方差协方差结构线性混合模型间的一致率平均为86%,品种产量效应排序在两种模型间也存在明显不同,品种产量效应估计的平均误差在最佳方差协方差结构线性混合模型小于在方差分析模型。 相似文献
16.
Summary The relative performance of synthetic varieties in faba beans (Vicia faba L.) as compared with line varieties is the result of the joint effect of several factors. Factors investigated in the present study were (1) effects of heterogeneity and (2) heterozygosity on agronomic performance, (3) genetic variance for the degree of cross-fertilization among inbred lines and (4) genetic variance among homozygous and heterozygous genotypes for yield. The evaluation was based on multilocational trials in Germany with 36 inbred lines and derived entries with contrasting population structure (levels of heterozygosity and heterogeneity). When inbred lines and F1-hybrids are included in the same mixture of genotypes, the resulting heterogeneity had a positive effect on yield. Relative mid-parent heterosis for yield was between 33% and 51%. The average degree of cross-fertilization was 53.5%, and its genetic standard deviation was 8.3%. The estimates for genetic standard deviation for yield among inbred lines were between 3.4 q/ha and 5.3 q/ha. The highest yielding synthetic variety is expected to outyield markedly the highest yielding line. 相似文献
17.
Summary 18 Hybrid Tea-rose varieties were crossed and selfed in an incomplete diallel. In F1 seedlings the relative contents of the flavonoids: pelargonidin, cyanidin, kaempferol and quercetin, were determined by means of paper chromatography. Inheritance of each pigment was mainly controlled by additive gene action. Combining ability analyses of variance of these pigments showed highly significant differences between GCA's of the varieties. The pigment content of parent varieties can be a useful basis for breeding. 相似文献
18.
Fernando López Anido Vanina Cravero Pablo Asprelli Teresa Firpo Stella Maris García Enrique Cointry 《Euphytica》2004,135(3):355-360
Heterotic response for total yield among five cultivar-groups of summer squash, Cocozelle, Vegetable Marrow, Zucchini, Crookneck
and Straightneck, was studied in two sets of diallel crosses evaluated in two harvest seasons. Each diallel cross included
two representatives of each the five cultivar-groups. Griffing and diallel GGE biplot (genotype main effect and interaction)
analyses were carried out. The relative importance of the specific combining ability variance on total variance was greater
than that reported earlier for intragroup crosses. Highly significant heterosis was manifested only in combinations of Crooknecks
or Straightnecks crossed to Cocozelles, Vegetable Marrows or Zucchinis. GGE biplots showed a consistent arrangement where
testers of ssp. texana interacted with cultivars of ssp. pepo and vice versa. We propose that the heterotic pattern of texana-pepo crosses could be potentially used to achieve increased yields in hybrids by introgressing one group into another in a manner
that would maintain fruit attributes of the cultivar-group.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
19.
Summary A population of 2xms sugar beets was crossed with 4x Beta lomatogona F. et M. The 3x F1-plants were male sterile and were backcrossed with 2x and 4x sugar beets and multiplied without pollination as well. After the 1st backcross mainly 3x apomict types arose again and, among others, a small number of successful 4x backcrosses. After pollination by 4x sugar beets this 4x F1 B1 produced. besides predominatly apomictically multiplied 4x plants, also about 7% haploid 2x hybrids. The latter probably possess 1 genome from B. vulgaris and 1 genome from B. lomatogona. In the meiosis of the PMC's a certain amount of homeology between a number of chromosomes of both species could be established. The amphihaploid hybrids can be used as breeding parents for the creation of types in which introgession can occur. During hybridization in addition to 2x and 4x B. vulgaris types a number of 2x-, 3x-, 5x- and 6x-hybrids arose. This is presumably caused by the presence of gametes with the somatic number of chromosomes and the occurrence sometimes of haploid apomictic multiplication.The presence of large numbers of bolters in the F1 and F1 B1 suggests that the bolting tendency of both species is based on different genes. 相似文献
20.
Akshay K. Pradhan Yaspal S. Sodhi Arundhati Mukhopadhyay Deepak Pental 《Euphytica》1993,69(3):219-229
Summary Divergence of 25 accessions of Brassica juncea of Indian, CIS (Commonwealth of Independent States, former USSR) and synthetic origin was studied by D2 analysis. On the basis of divergence, ten accessions were selected and crossed in a diallel fashion without reciprocals to study the combining ability and heterosis. None of the accessions was found to be a good general combiner for all the nine quantitative characters that were studied. Significant heterosis over better parent for single plant yield was recorded in CIS x Indian and synthetic x CIS crosses (5 each) followed by Indian x synthetic types (3). The analysis of component characters showed that the mean performance of the majority of hybrids was intermediate for five out of six yield attributing traits, thus exhibiting dominance or partial dominance effect. To estimate the contribution of such yield attributing traits towards heterosis for yield, a comparison was made among three parameters viz. heterosis over mid parent (MP), better parent (BP) and better yielding parent (BYP) of the concerned hybrid. It was observed that estimation of heterosis from BYP was a more accurate method to determine the contribution of component characters towards yield heterosis than the analysis based on MP and BP. From the component character analysis, it was concluded that characters like number of primary and secondary branches, number of siliqua per plant and siliqua density contributed significantly towards heterosis in yield. Plot level yield trials of two selected hybrids (Skorospieka II x RH30 and Donskaja IV x Varuna) over two growing seasons revealed 29.4 to 91.8% heterosis over BYP. 相似文献