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Kebebew Assefa Seyfu Ketema Hailu Tefera Henry T. Nguyen Abraham Blum Mulu Ayele Guihua Bai Belay Simane Tiruneh Kefyalew 《Euphytica》1999,106(1):87-97
Three hundred twenty germplasm lines of the major Ethiopian cereal, tef, [ Eragrostis tef (Zucc.) Trotter], were evaluated
for 20 morphological, phenological and agronomic characters in two-replicated randomized complete blocks at Debre Zeit and
Melkassa Agricultural Research Centers in Ethiopia during the 1995 main season. The objectives were to assess the diversity
of the lines, and to estimate the broad sense heritability (H) and genetic advance (GA) of the various characters. The mean
squares of genotypes were highly significant (p ≤ 0.001) for all the traits. The phenotypic and genotypic coefficients of
variation ranged in that order from about 6–40% and 3–23% for days to maturity and grain yield/plant, and days to maturity
and number of spikelets/main shoot panicle, respectively. The cluster analysis grouped the genotypes into 14 major complexes
consisting of one to 183 lines. Of the 19 principal components involved in explaining the entire variation among the genotypes
the first five which had eigenvalues of more than one explained about 73.8%. The first principal component which accounted
for about 34% of the total variance was due chiefly to plant height, culm and panicle length, diameters of the two basal culm
internodes, main shoot panicle mass and grain yield, number of main shoot panicle branches and spikelets, and days to panicle
emergence and maturity. Estimates of H varied from about 22% for length of the lowest main shoot stem internode to 74% for
number of main shoot panicle branches. Values of GA (expected from selection of the superior 5% of the lines and expressed
relative to the means) ranged from about 3% for days to maturity to 36% for number of spikelets/main shoot panicle. Overall,
the study indicated the existence of trait diversity in tef germplasm and this can be exploited in the genetic improvement
of the crop through hybridization and selection.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
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Temesgen?AdnewEmail author Seyfu?Ketema Hailu?Tefera H.?Sridhara 《Genetic Resources and Crop Evolution》2005,52(7):891-902
One hundred and forty-four heterogeneous tef germplasm accessions collected from 10 major tef growing areas in Ethiopia were
evaluated for 18 quantitative traits in a simple lattice design, at Holetta and Ginchi, in 2001 main growing season to study
the genetic diversity in tef. The combined analysis of variance revealed the presence of significant variation among germplasm
accessions for all traits studied. Cluster analysis revealed the overlapping of the germplasm accessions from different origin
and the accessions were grouped into eight distinct clusters of 1–78. Generalized distance square confirmed the presence of
significant genetic distance between clusters. In principal component (Prin) analysis, the first four principal components
with latent root values above one accounted for about 80.6% of the variability existing among the germplasm accessions. Prin1
constituted about 55% of the variability mainly from almost equal contribution of 10 quantitative traits, indicating that
most of the traits are equally important in tef diversity. In this study, the regions and altitudes of origin were not found
to have a substantial effect on the genetic diversity in tef germplasm. Diversity within the regions was found to be significant
and, hence, an opportunity for exploitation in tef improvement. 相似文献
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The study was conducted to evaluate surge irrigation against continuous irrigation in terms of irrigation and water use efficiencies
to produce onion. It was carried out at Mekelle Agricultural Research Center, Ethiopia on 70 m long and 0.6 m center–center
spacing furrows of 0.26% average slope on a clay soil. The treatments consisted of factorial combination of two discharges
(Q
1 = 1 l/s and Q
2 = 2 l/s) and three-cycle ratios (CR1 = 1/3, CR2 = 1/2, and C = 1 for continuous irrigation). Surge flow treatments advanced faster than the respective continuous flow treatments with
surge flow treatment SF21 being the fastest. The best value of application efficiency (60%) was achieved for SF11 and the least (46%) for CF2. The maximum (87%) and minimum (68%) values of distribution uniformity were obtained for cycle ratios CR1 and C, respectively. Storage efficiency was highest (89%) for CF2 and lowest (78%) for SF12. Onion yield was significantly affected (p < 0.05) by the interaction effect, the highest (14,400 kg/ha) and the lowest (13,363 kg/ha) yields were obtained for SF11 and SF21, respectively. The maximum irrigation water use efficiency (2.27 kg/m3) was observed for SF11 and the minimum (1.68 kg/m3) for CF2. Surge irrigation was found to be a promising irrigation practice for onion production in the study area as it saves water,
reduces irrigation period, and increases the crop yield. 相似文献
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Field evaluation of surface irrigation systems play a fundamental role to determine the efficiency of the system as it is
being used and to identify management practices and system configurations that can be implemented to improve the irrigation
efficiency. This study evaluated the performance of an ‘improved’ traditional small-scale irrigation practice at Adada, a
representative small-scale irrigation practice in Dire Dawa Administrative Council, Eastern Ethiopia. In order to determine
numerical values of performance measures, certain parameters were measured/observed before, during and after an irrigation
event while farmers are performing their normal irrigation practice. These parameters include: irrigated crop, irrigation
method, stream size, cutoff time, soil moisture deficiency, and field size, shape and spacing. The results showed that the
irrigation water applied to a farmer's plot during an irrigation event/turn was generally higher than the required depth to
be applied per event. Since the irrigation method used was end-dyked, the major cause of water loss was due to deep percolation.
The deep percolation loss was 32% in sorghum, 57% in maize, and 70% in tomato and potato fields. The type of irrigation system
used, the ridged irrigation practice and the poor irrigation scheduling in the study sites were the main problems identified
in the management and operations of the schemes. The following corrective measures are recommended to improve the system:
(1) farmers should regulate the depth of irrigation water they apply according to the type of crop and its growth stage, change
the field irrigation system and/or configuration especially for shallow rooted row crops, to furrow system, (2) guidance and
support to farmers in developing and introduction of appropriate irrigation scheduling, and (3) future development interventions
towards improvement of traditional irrigation practices should also focus in improving the on farm irrigation systems in addition
to improving physical infrastructure of the scheme. 相似文献
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A study was undertaken to evaluate the performance of sand-traps at Wonji-Shoa Sugar Estate, Ethiopia. Inflow and outflow samples from the sand-traps and deposited sediment samples from the sand-traps, main canal, and reservoirs were taken. The samples were analyzed for sediment concentration and particle size distribution. During the study period, the sand-traps were performing satisfactorily in removing a good portion of suspended sediment (as high as 63% in case of sand-trap A and 54% in case of sand-trap B) in the week after flushing and they were performing poor (as low as −40% in case of sand-trap A and 6% in case of sand-trap B) when the sand-trap was running without flushing for about two months. Sediment particle size analyses of the samples indicated that the sand-traps retained almost all the sand fractions (90–95%) greater than 0.15 mm. Fifty to sixty percent of the sediment particles passing the sand-traps into the main canal was smaller than 0.002 mm. Sieve analyses of the bed materials taken from the sand-traps showed that particles up to medium gravel size (6.3–13.2mm) were entering the sand-traps and almost all were trapped. This result shows that performance of the sand-traps under the existing sediment load of Awash River was found to be satisfactory. However, it was observed that performance level of the sand-traps was very much dependent on the flushing interval of deposited sediment. 相似文献
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Improved water management through precise crop water requirement determination is needed to improve the efficiency of water
use in agricultural production. As a result, appropriate irrigation scheduling which can lead to water saving, improvements
in the yield and income can be designed. In this study, three non-weighing lysimeters having dimensions of 2 m × 1 m × 2 m
were used to determine water requirement (ETc) and crop coefficient (Kc) of onion (Bombay Red cultivar). Reference crop evapotranspiration (ETo) was determined using weather data recorded at the site. The measured ETc values were 51.3 mm, 140.5 mm, 144.8 mm, and 53.9 mm during the initial, development, mid-season and late season growth stages
respectively. Crop coefficient (Kc) values, calculated as ratio of ETc to ETo, were 0.47, 0.99, and 0.46 during the initial and mid-season stages and end of late season. Furthermore, third-order polynomials
were fitted well to predict the crop coefficient values as functions of growing degree-days (GDD). 相似文献
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