scholarly journals Genetic Variances and Heritabilities of Traits of an Early Yellow Maize Population after Cycles of Improvement for Striga Resistance and Drought Tolerance

Crop Science ◽  
2018 ◽  
Vol 58 (6) ◽  
pp. 2261-2273 ◽  
Author(s):  
B. Badu-Apraku ◽  
B. E. Ifie ◽  
A. O. Talabi ◽  
E. Obeng-Bio ◽  
R. Asiedu
Keyword(s):  
Drought Tolerance ◽  
Genetic Variances ◽  
Maize Population ◽  
Striga Resistance

Changes in genetic variances and heritabilities in an early white maize population following S1 selection for grain yield, Striga resistance and drought tolerance

2016 ◽  
Vol 155 (4) ◽  
pp. 629-642 ◽  
Author(s):  
B. BADU-APRAKU ◽  
M. OYEKUNLE ◽  
A. O. TALABI ◽  
B. ANNOR ◽  
I. C. AKAOGU
Keyword(s):  
Drought Tolerance ◽  
Grain Yield ◽  
Recurrent Selection ◽  
Central Africa ◽  
Maize Production ◽  
Genetic Variances ◽  
Maize Population ◽  
Ear Height ◽  
Selection For ◽  
Advanced Cycles

SUMMARYDrought is a major constraint to maize production in West and Central Africa (WCA). Assessment of genetic gain from S1 recurrent selection under drought is crucial for the development of drought tolerance breeding strategies. In an early white population, 60 S1 families each derived from the base population and three cycles of selection were evaluated under drought and well-watered conditions at two locations in Nigeria for 2 years to determine genetic variability, gains from selection and predict response to selection for grain yield and other traits. Genetic variances generally decreased for yield and other traits in advanced cycles under drought and well-watered conditions except yield and ear height under well-watered conditions. Similarly, heritabilities for yield and other traits decreased in advanced cycles under drought but increased in advanced cycles under well-watered conditions. Realized gain for yield was 0·291 t/ha, corresponding to 30·5% per cycle under drought and 0·352 kg/ha with a corresponding gain of 16·7% per cycle under well-watered conditions. Predicted gain based on C3 was 0·282 and 0·583 t/ha under drought and well-watered conditions. Low genetic variances, heritabilities and predicted gain for yield and other traits suggested a need to introgress drought tolerance genes into the population.

Effects of drought screening methodology on genetic variances and covariances in Pool 16 DT maize population

2004 ◽  
Vol 142 (4) ◽  
pp. 445-452 ◽  
Author(s):  
B. BADU-APRAKU ◽  
M. A. B. FAKOREDE ◽  
A. MENKIR ◽  
A. Y. KAMARA ◽  
A. ADAM
Keyword(s):  
Genetic Variances ◽  
Maize Population ◽  
Effects Of Drought ◽  
Drought Screening

Genetic gains in grain yield under nitrogen stress following three decades of breeding for drought tolerance and Striga resistance in early maturing maize

2015 ◽  
Vol 154 (4) ◽  
pp. 647-661 ◽  
Author(s):  
B. BADU-APRAKU ◽  
M. A. B. FAKOREDE ◽  
M. OYEKUNLE ◽  
R. O. AKINWALE
Keyword(s):  
Drought Tolerance ◽  
Grain Yield ◽  
Central Africa ◽  
Striga Hermonthica ◽  
Maize Cultivars ◽  
Maize Populations ◽  
Striga Resistance ◽  
Early Maturing ◽  
West And Central Africa ◽  
N Rates

SUMMARYBreeding for resistance to Striga hermonthica Del. (Benth) and tolerance to drought has been a major strategy to improve maize (Zea mays L.) production and productivity in West and Central Africa during the last three decades. The three decades consisted of three breeding periods or eras based on the germplasm and methodologies used; that is, 1988–2000, 2001–06 and 2007–11. A total of 50 early maturing cultivars, combining Striga resistance with drought tolerance were developed, including 15, 16 and 19 cultivars for the three periods, respectively. Although the cultivars were not selected intentionally for low-nitrogen (N) tolerance, it was hypothesized that tolerance to low-N had been significantly improved while selecting for drought tolerance and Striga resistance. This hypothesis was tested by evaluating the 50 cultivars in 2010 and 2011 in Nigeria at Mokwa and Ile-Ife under both low-N (30 kg N/ha) and high-N (90 kg N/ha) levels. Under low-N conditions, grain yield improved from 2280 kg/ha during the first period to 2610 kg/ha during the third period, an increase of 165 kg/ha per period with r2 of 0·99. Under high-N, yield increased from 3200 to 3650 kg/ha, an increase of 225 kg/ha and r2 of 0·93. Relative gain per period was 30 kg/ha for the two N rates with r2 values of 0·99 and 0·94 respectively. Grain yield performance of the 50 cultivars under low-N conditions adequately predicted their performance under high-N. Selection for Striga resistance and drought tolerance in early maturing maize populations enhanced low-N tolerance in the maize cultivars derived from the populations. The improvement was higher in later than earlier breeding periods.

scholarly journals Identification of QTLs Controlling Resistance/Tolerance to Striga hermonthica in an Extra-Early Maturing Yellow Maize Population

Agronomy ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1168 ◽  
Author(s):  
Baffour Badu-Apraku ◽  
Samuel Adewale ◽  
Agre Paterne ◽  
Melaku Gedil ◽  
Robert Asiedu
Keyword(s):  
Candidate Genes ◽  
Marker Assisted Selection ◽  
Defense Mechanisms ◽  
Sub Saharan Africa ◽  
Striga Hermonthica ◽  
Maize Production ◽  
Maize Population ◽  
Striga Resistance ◽  
Sub Saharan ◽  
Indicator Traits

Striga hermonthica parasitism is a major constraint to maize production in sub-Saharan Africa with yield losses reaching 100% under severe infestation. The application of marker-assisted selection is highly promising for accelerating breeding for Striga resistance/tolerance in maize but requires the identification of quantitative trait loci (QTLs) linked to Striga resistance/tolerance traits. In the present study, 194 F2:3 families of TZEEI 79 × TZdEEI 11 were screened at two Striga-endemic locations in Nigeria, to identify QTLs associated with S. hermonthica resistance/tolerance and underlying putative candidate genes. A genetic map was constructed using 1139 filtered DArTseq markers distributed across the 10 maize chromosomes, covering 2016 cM, with mean genetic distance of 1.70 cM. Twelve minor and major QTLs were identified for four Striga resistance/tolerance adaptive traits, explaining 19.4%, 34.9%, 14.2% and 3.2% of observed phenotypic variation for grain yield, ears per plant, Striga damage and emerged Striga plants, respectively. The QTLs were found to be linked to candidate genes which may be associated with plant defense mechanisms in S. hermonthica infested environments. The results of this study provide insights into the genetic architecture of S. hermonthica resistance/tolerance indicator traits which could be employed for marker-assisted selection to accelerate efficient transfer host plant resistance genes to susceptible genotypes.

scholarly journals Number of recombinations and genetic properties of a maize population undergoing recurrent selection

2009 ◽  
Vol 66 (1) ◽  
pp. 52-58 ◽  
Author(s):  
Francisco Pinheiro Lima Neto ◽  
Cláudio Lopes de Souza Júnior
Keyword(s):  
Genetic Variability ◽  
Grain Yield ◽  
Recurrent Selection ◽  
Genetic Correlations ◽  
Selection Cycle ◽  
Genetic Variances ◽  
Maize Population ◽  
Two Generations ◽  
Gametic Phase Disequilibrium ◽  
Gametic Phase

In maize recurrent selection programs, selected genotypes were recombined once to generate genetic variability for the next selection cycle. Selection generates negative gametic phase disequilibrium which reduces genetic variances, and this disequilibrium is not significantly reduced with only one generation of recombination. The objective of this research was to assess the effects of one additional generation of recombination on phenotypic and genotypic parameters in a maize population undergoing recurrent selection. Selected progenies of the EPB-4 population were subjected to one and two generations of recombination, and from each generation half- and full-sib progenies were developed and evaluated at three environments for grain yield, plant and ear heights, prolificacy, and ear placement. There were no significant changes between each progeny type with one and two generations of recombination for the means, ranges, phenotypic distribution of the traits, genetic variances, heritability coefficients, and genetic correlations for the traits assessed. The results suggest that an additional generation of recombination will not increase the effectiveness of maize recurrent selection programs.

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