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41.
C. Fortes Ferreira M. Gonzaga Pereira A. da Silva dos Santos R. Rodrigues R.E. Bressan-Smith A. PioViana R. Figueiredo Daher 《Euphytica》2003,134(1):43-46
Among the main causes of poor yield in common beans are fungal, viral and bacterial diseases. Common bacterial blight, caused
by Xanthomonas axonopodis pv. phaseoli (Xap), is one of the major bacterial diseases leading to significant losses in Brazil. Chemical control is ineffective, therefore,
the use of resistant varieties becomes an interesting alternative. The objective of the present work was to evaluate disease
resistance under natural infection of the pathogen in 109 recombinant inbred lines (F7) of P. vulgaris originated from the cross HAB-52 (susceptible — snapbean) × BAC-6 (resistant — common bean) in two different environments,
as well as to calculate genetic parameters to assist in the selection of promising materials to be used in the CBB resistance
breeding program. The data of the genetic parameters were
compared to those calculated for the F3 generation originated from the same cross. The heritability results for DI (disease index) and VI (variation index) in F3 were 26.85% and 0.26, respectively, whereas in F7 they were 91.77% and 1.36, respectively. These results demonstrate a potential to be explored for this advanced population,
that in the future, along with other pathogen variability studies and tests in other environments, may provide more information
regarding a more precise evaluation of promising genotypes to be used in common bean breeding programs aiming to obtain CBB
resistant varieties.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
42.
The objective of this study was to investigate the origin of chromosome segments of maize (Zea mays L.) inbred B86 from its parental inbreds B52 and Oh43 using RFLPS. B86 was selected to combine resistance to the first and second brood of the European corn borer with the favorable agronomic performance of Oh43. RFLP analyses of the three inbreds were performed with three restriction enzymes (EcoRI, EcoRV, HindIII) and 178 DNA probes covering all ten maize chromosomes. For two DNA probes in combination with one enzyme, B86 showed a new RFLP pattern not present in the two parents. Based on results from 119 polymorphic DNA probes, the proportion of the B86 genome contributed by B52 (51.3 %) and Oh43 (48.7 %) was almost equal. 相似文献
43.
Summary The early growth of 96 genotypes of tomato was studied at 320 ppm CO2 and at 750 ppm CO2 in separate climate rooms. Plants were harvested at 40 and 55 days after sowing. Fresh and dry weights were determined. Large differences between genotypes were found for average plant fresh and dry weights and for relative growth rates. The average overall growth enhancement by CO2 enrichment was 2.3. Two genotypes showed significant genotype x CO2 interaction. The consequences of these results for tomato breeding are discussed. 相似文献
44.
Crosses were made between four spring barley (Hordeum vulgare L.) cultivars and five F1, hybrids with one genotype of Hordeum bulbosum L. in two locations to investigate further previous low crossabilities which had been found in the barley cultivar ‘Apex’ with H. bulbosum. Data at all the main steps of the H. bulbosum technique were recorded and statistically analyzed. Significant differences between barley genotypes were demonstrated for all characters. It was confirmed that ‘Apex’ has poor crossability with H. bulbosum. Out of the three F1 hybrids having ‘Apex’ as one parent, two exhibited low crossability similarly to ‘Apex’ but one showed significantly higher seed setting than ‘Apex’. The effect of the location was only significant on seed setting, while genotype X location interactions were significant on seed setting, seed quality and rate of haploid plants in relation 10 florets pollinated. Another problem which has influenced the success rate of the H. bulbosum method was found in the cultivar ‘Havilla’. Although seed setting and seed quality were high for this cultivar, embryo differentiation was low. However, this latter problem was found to influence less the overall success rate than poor crossability. Mahalanobis's distances were calculated and the dendrite of the shortest distances between barley genotypes was plotted. 相似文献
45.
基于生理发育时间的棉花生育期模拟模型 总被引:35,自引:2,他引:35
棉花生育期模拟是研究棉花生长与环境因子关系的重要内容。通过分析春播中(中早)熟常规棉、中(中早)熟转基因抗虫棉和夏播早熟短季棉三种类型16个品种(系)的生育期与环境因素的动态关系,建立了以棉花生理发育时间(PDT)为基础的棉花生育期模拟模型。模型考虑了热效应、光周期效应、品种早熟性及地膜覆盖地积温对气积温的补偿效应。利用不同年份、生态区、基因型品种、栽培措施的试验资料对模型进行了检验,结果表明不同品种生育期模拟值与观测值的符合度较好,各生育进程的RMSE在1.4~4.9d。模型既有较强的机理性,又有较好的适用性。 相似文献
46.
Frew Mekbib 《Euphytica》2003,130(2):147-153
An experiment was undertaken to determine the stability of seed yield in 21 common bean genotypes representing three growth
habits. Seven genotypes in each growth habit (determinate bush, indeterminate bush and indeterminate prostrate) were evaluated
in replicated trials at three locations for three years under rain fed conditions in Ethiopia. A combined analysis of variance,
stability statistics and rank correlations among stability statistics and yield-stability statistic were determined. The genotypes
differed significantly for seed yield and genotype × environment (year by location) interaction (GE). The different stability
statistics namely Type1, Type 2 and Type 3 measured the different aspects of stability. This was substantiated by rank correlation
coefficient. There were strong rank correlations among Si
2d, Wi
2,σi
2 and Si
2, where as there was weak correlation between biand Ri
2, Si
2d, Wi
2, σi
2 and Si
2. R2 was significantly and negatively correlated with Wi
2, σi
2 and Si
2. σi
2 is significantly correlated with Wi
2.Yield is significantly correlated with bi and Ri
2.None of the statistics per se was useful for selecting high yielding and stable genotypes except the YS(yield-stability statistic). Most of the high yielding
genotypes were relatively stable. Of the 21 genotypes, only 11genotypes were selected for their high yielding and stable performance.
Genotypes with growth habit III and I (in determinate prostrate and determinate bush) were generally more stable than in determinate
bush.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
47.
Anne Elings 《Euphytica》1993,70(1-2):85-96
Syrian durum wheat landraces from diverse collection sites were evaluated for agronomic performance under arid conditions over two seasons at four locations, at two levels of nutrient availability.Grain yield differed considerably among locations. Within locations, significant population and fertilizer effects were demonstrated. In most cases, maximum yield was achieved by landraces, which demonstrates the breeding value of local germplasm. In a particular environment, the population effect was nonsignificant for total dry matter production, but significant for straw and grain yield. Nitrogen application was ineffective if moisture availability was the dominant growth limiting factor.Correlations between plant characteristics at evaluation and collection site characteristics were limited, and therefore, their utilization in germplasm evaluation appear limited. The negative relation between grain yield and soil nitrogen content at the collection site may be caused by the comparative disadvantage that germplasm from regions with favourable growing conditions has under low-yielding conditions.Particular environmental conditions at the collection site were no indicator for the response to changed growing conditions. Relatively high grain yields under good and adverse growing conditions excluded each other in all but two cases. Also, it was difficult to relate grain yield to regions of collection, as the response of individual landraces from a certain region to changing growing conditions differed strongly. Differentiation on the basis of landrace groups appears more promising. The Hauran landrace group provided the largest number of populations with relatively high grain yields over diverse environments. 相似文献
48.
Adaptation of seven complete and twelve substituted triticales to specific soil types has been studied, based on a series of twenty trials carried out in 1989 and 1990 across Spain. The nature of the GE interaction for grain yield was revealed by means of the additive main effects multiplicative interaction (AMMI) model and using the soil pH at the different sites as linear covariate. The percentage of the variability explained by the first principal component axis of the AMMI model was 72 and 65 % for the two years, suggesting a specific pattern of adaptation. Soil pH was the single most important environmental factor to explain the adaptation of complete and substituted types. Complete triticales outyielded substituted genotypes in the majority of sites. Triticale adaptation to acid and alkaline soils seems to be largely controlled by the single wheat/rye chromosome 2D(2R) substitution, for which both types differ. Complete triticales seem better adapted to the acid soils, whereas substituted types are, in general, more suited to alkaline soils. 相似文献
49.
Summary The paper addresses the general question of identifying the optimum environment for selection in plant breeding programs for low input agricultural systems. After defining low-yielding and high-yielding environments based on the average grain yield of large numbers of barley genotypes in different cropping seasons, we examined: 1) the phenotypic relationships between the highest yielding genotypes in low- and high-yielding environments, and 2) the genetic correlation coefficients between grain yield in low- and high-yielding environments. The results indicate that the alleles controlling high grain yield in low-yielding conditions are at least partially different from those controlling high grain yield in high-yielding conditions. Therefore, selection in high-yielding environments is expected to produce a negative response or no response in low-yielding environments. This may explain why crop varieties bred under high-yielding conditions failed to have an impact in low-yielding agricultural systems. The results may be extrapolated to systems where environmental concern suggests a reduction of inputs by raising the question of whether crop breeding programs based on selection under high inputs are likely to generate the right type of germplasm for an environmentally friendly agriculture. 相似文献
50.
Two populations of common bean, Phaseolus vulgaris L., were used to make three independent location-specific selections at Palmira, Quilichao, and Popayán, Colombia. Also, three across-location selections were made by alternating generations between Palmira and Popayan, between Quilichao and Popayán, and among Palmira, Quilichao, and Popayán. The seven highest yielding lines selected from each environment and population along with 14 parents and two checks were evaluated for seed yield, seed weight, maturity, and reaction to an-thracnose, angular leaf spot, and common bacterial blight. Mean squares due to evaluation and selection environments, selected lines, and their interactions were significant for all traits. Mean yields of selected lines were higher than the mean of parents in both populations. Among location-specific selections, lines yielded higher at their respective selection site. Moreover, selections made at Popayán were higher yielding than those made at Quilichao or Palmira when tested across locations and years. Use of Popayán, a relatively wetter and cooler site, either alone or in combination with other locations resulted in higher yield, higher seed weight, and higher resistance to anthracnose. On the average, location-specific selections were lower yielding than the across-location selections. Among across-location selections, those selected between Palmira and Popayán were the highest yielding in both populations. Selections at Palmira and across all three locations resulted in greater stability. 相似文献