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1.
Recombinant inbred lines (RILs) of the tef cross Kaye Murri × Fesho were evaluated for nine quantitative traits at three locations
in the central highlands of Ethiopia during the 1998/99 main season in order to estimate the genetic coefficient of variation
(GCV), heritability and genetic advance expected from selection. Highly significant differences were obtained among the RILs
for all traits studied. Grain yield, panicle weight and yield per panicle showed a relatively high GCV (12–16%). A comparatively
high heritability was obtained from days to heading (31%) followed by panicle length (25%) and grain yield (23%). Moderate
amounts of heritability values were obtained for panicle weight and yield per panicle. High genetic advance as percent of
the mean were obtained from grain yield (16%), yield per panicle (12%) and panicle weight (10%) at5% selection intensity,
which indicated the possibility of improving these traits. Several RILs were identified that have exceeded the better yielding
parent at all locations. Grain yield showed a strong positive association (r = 0.26–0.70) with shoot biomass, lodging index,
panicle length, plant height, panicle weight and yield per panicle. Overall, the present results showed a) the availability
of genetic variance for some useful traits in the RILs for exploitation through selection, b) the existence of significant
genotype × location interaction that indicated the need to test inbred populations in more environments, and c)the availability
of superior inbred lines for further breeding work.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
2.
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
3.
4.
Variable corn emergence results in decreased yields. This study was conducted to determine corn (Zea mays L.) by-plant yield reduction arising from delayed emergence. Treatments included delayed planting of 0, 2, 5, 8, and 12 days at two nitrogen (N) rates. Corn was planted by hand to maintain 17.8 cm plant-to-plant competition. Fifteen plants within a row were divided into five 3-plant sequences (middle plant delayed and 2-adjacent non-delayed plants). Under irrigation, grain yields decreased when the middle plant was delayed 2, 5, 8, and 12 days, by 3, 10, 19, and 25%, respectively. At the rainfed site, grain yields decreased when the middle plant was delayed 2, 5, 8, and 12 days, by 14, 25, 23, and 11%, respectively. Over all sites and years, for each day delay in emergence (one out of every 3 plants), corn grain yields decreased 0.225 to 1.379 Mg ha?1 day?1. 相似文献
5.
Jagadeesh Mosali Kefyalew Desta Roger K. Teal Kyle W. Freeman Kent L. Martin Jason W. Lawles 《Journal of plant nutrition》2013,36(12):2147-2163
ABSTRACT One would expect foliar applied phosphorus (P) to have higher use efficiencies than when applied to the soil, but limited information is available concerning this. Experiments were conducted in 2002, 2003, and 2004 to determine the effect of foliar applications of P on winter wheat grain yields, P uptake, and use efficiency. Twelve treatments containing varying foliar P rates (0, 1, 2, and 4 kg ha? 1 in 2002 and 2003 and additional 8, 12, 16, and 20 kg ha? 1 in 2004) with and without pre-plant rates of 30 kg ha? 1 were evaluated. Foliar applications of P at Feekes 7 generally increased grain yields and P uptake versus no foliar P. Use efficiency was higher when P was applied at Feekes 10.54. Results from this study suggested that low rates of foliar applied P might correct mid-season P deficiency in winter wheat, and that might result in higher P use efficiencies. 相似文献
6.
K. W. Freeman Kefyalew Girma R. K. Teal D. B. Arnall B. Tubana S. Holtz 《Journal of plant nutrition》2013,36(12):2021-2036
ABSTRACT Crop management strategies that improve Nitrogen Use Efficiency (NUE) increase profits while reducing the detrimental effects on the environment associated with fertilizer nitrogen (N) loss. Effective N management should include several critical factors that are very interrelated. A study was conducted at the Panhandle Research and Extension Center, Goodwell, OK to evaluate the effects of multiple nitrogen management practices including N rate, source, time of application, methods of fertilizer and residue incorporation over a long period of time on grain yield, N uptake and NUE in irrigated corn. Fourteen treatments were evaluated in a randomized complete block design with three replicates. Results of data analyzed on the individual year and averages of all years showed that grain yield and N uptake were improved with N rates and N management practices compared to checks. Both N recovery and efficiency of use were high for the 118 kg N ha? 1 rate. 相似文献
7.
Kefyalew Girma Starr Holtz Brenda Tubaña John Solie William Raun 《Journal of plant nutrition》2013,36(2):165-182
Midseason fertilizer nitrogen (N) rates based on predicted yields can be projected if the quantity of N accumulated in winter wheat (Triticum aestivum L.) and corn (Zea mays L.) is known especially early in the growing season. This study was conducted in 2006 and 2007 to establish the amount of N accumulated in corn and winter wheat over the entire growing season. Plots representing three N fertilization rates 0, 45, and 90 kg ha?1 at Stillwater and 0, 67, and 112 kg ha?1 at Lahoma were selected from two long-term wheat experiments located at research stations in Stillwater and Lahoma, Oklahoma. For corn, three N fertilization rates 0, 112 and 224 kg ha?1 at Lake Carl Blackwell and 0, 56 and 112 kg ha?1 at Perkins were selected from N studies, located at research stations near Lake Carl Blackwell and Perkins, Oklahoma. Sequential aboveground biomass samples were collected from 1 m2 area of wheat and 1.5 m long row (0.76 cm spacing) for corn throughout their respective growing seasons. In general, this work showed that more than 45% of the maximum total N accumulated could be found in corn plants by growth stage V8 (8th leaf collar fully unfolded). For winter wheat, more than 61% of the maximum total N accumulated at later stages of growth could be accounted for by Feekes growth stage 5 (F5, leaf strongly erected). Our findings are consistent with those of others showing that yield potential can be predicted at mid-season since such a large percentage of the total N accumulated was accounted for early on in the growing cycle of either wheat or corn. 相似文献
8.
Kefyalew Girma J. Mosali K. W. Freeman W. R. Raun K. L. Martin W. E. Thomason 《Journal of plant nutrition》2013,36(9):1541-1553
ABSTRACT Recently, environmental quality issues related to sulfur (S) have made it necessary to reduce its release into the atmosphere in wet or dry forms, which in turn might influence the S requirement of crops. It is anticipated that by 2020, S deposition will decrease by up to 30% in eastern portions of Oklahoma and by 15% throughout the remainder of the state. This change calls for frequent monitoring and evaluation of S nutrition in wheat and other crops. Experiments were conducted at Hennessey and Perkins research stations for a period of seven years starting in the fall of 1996, with the objective of assessing the effect of different levels of elemental and sulfate-S fertilizers on the grain and forage yields of winter wheat in Oklahoma. The experimental design was a randomized complete block with three replications. Four S rates, 0, 56, 112, and 224 kg S ha? 1, were applied to the plots from 1996 to 2002 as CaSO4. Another two rates, 56 and 112 kg S ha? 1, were included in the trials beginning in 1998 using 92% elemental S. Gypsum, as a source of S for winter wheat, resulted in a greater yield than did elemental S in cases where S fertilizer sources were deemed significant. In six of 14 trials from 1996 to 2002, applied S as CaSO4 significantly increased wheat-grain yields. Observing significant grain and forage yield increases due to applied S was important, but the response was sporadic and unpredictable from one year to the next. 相似文献
9.
Daryl B. Arnall Brenda S. Tubaña Starr L. Holtz Kefyalew Girma W. R. Raun 《Journal of plant nutrition》2013,36(3):502-515
Although nitrogen use efficiency (NUE) of small grains is well documented at 33% worldwide, there has been little research relating NUE to yield factors. This study examined the relationship between NUE and the response index at harvest (RIHARVEST) of winter wheat (Triticum aestivum L.). Yield data from a long-term fertility study established at Lahoma, Oklahoma in 1971 was used to explore the relationship. In this report, six nitrogen (N) rates at non-limiting levels of P and K were evaluated. Regression analysis showed a positive relationship between NUE and RIHARVEST for all years across all N rates (r2 = 0.37). But this relationship was improved (r2 = 0.45) when both RINDVI and RIHARVEST were included in the model. The linear relationship between NUE and RIHARVEST was significantly improved, when yield data and corresponding NUE were separated according to the annually applied fixed N rate. As the N rate increased the resulting slope of the relationship between NUE and RI was reduced. These analyses also demonstrate that temporal variability in NUE exists and that NUE can be predicted. 相似文献
10.
Apurba K. Sutradhar Eric C. Miller Daryl B. Arnall Bruce L. Dunn Kefyalew Girma William R. Raun 《Journal of plant nutrition》2017,40(17):2382-2391
Information is limited on using winter legumes as a source of nitrogen (N) intercropped with switchgrass in the southern Great Plains of the United States. The objectives of this study were to evaluate N contribution of several winter legumes to switchgrass, and to determine the influence of winter legumes on biofuel quality and soil fertility status. Field experiments were conducted at two locations in Oklahoma in which six winter legumes and four rates of N fertilizer were studied over a 3-year period. Winter legumes did not increase switchgrass forage yield, cellulose, lignin, and hemicellulose concentrations at any location. Soil organic matter (OM), nitrate-N (NO3-N), soil test phosphorus (P), soil test potassium (K), and soil pH remained unchanged. In contrast, applying inorganic N only increased switchgrass yield. This study demonstrated that southern Great Plains may not be conducive to utilizing legumes as the primary N source for switchgrass. 相似文献