scholarly journals Combining Ability of Extra-Early Maize Inbreds Derived from a Cross between Maize and Zea diploperennis and Hybrid Performance under Contrasting Environments

Agronomy ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1069
Author(s):  
Isaac K. Amegbor ◽  
Baffour Badu-Apraku ◽  
Gloria B. Adu ◽  
Joseph Adjebeng-Danquah ◽  
Johnson Toyinbo
Keyword(s):  
Grain Yield ◽  
Combining Ability ◽  
Sub Saharan Africa ◽  
Hybrid Breeding ◽  
Optimal Conditions ◽  
Breeding Programs ◽  
Rainfed Conditions ◽  
Genetic Mechanisms ◽  
Maize Inbreds ◽  
Sub Saharan

Knowledge of the genetic mechanisms conditioning drought tolerance in maize is crucial to the success of hybrid breeding programs aimed at developing high-yielding cultivars under drought. The objectives of this study were to determine the combining ability of extra-early inbreds, compute the heritability of measured traits, assess the performance of inbreds in hybrid combinations and investigate the associations among traits under drought and optimal conditions. A total of 252 hybrids generated by crossing 63 inbreds to four testers, along with four commercial hybrid checks, were evaluated for 2 years under drought and rainfed conditions. General combining ability (GCA) and specific combining ability (SCA) for the traits were significant. A total of 57.1% and 53.4% of the genotypic sum of squares were attributable to GCA effects for grain yield under managed drought and rainfed conditions, respectively. Hybrids TZdEEI 91 × TZEEI 21 and TZdEEI 55 × TZEEI 13 out-yielded the best checks under drought and optimal conditions by 49.13% and 39.05%, respectively. The most promising hybrids with consistently high grain yield under drought and rainfed conditions, were TZdEEI 54 × TZEEI 13, TZdEEI 91 × TZEEI 21 and TZdEEI 55 × TZEEI 21 and should be further evaluated for possible commercial production in sub-Saharan Africa.

scholarly journals Genetic Gains from Selection for Drought Tolerance during Three Breeding Periods in Extra-Early Maturing Maize Hybrids under Drought and Rainfed Environments

Agronomy ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 831
Author(s):  
Baffour Badu-Apraku ◽  
Oluwafemi Obisesan ◽  
Adeoti Abiodun ◽  
Ebenezer Obeng-Bio
Keyword(s):  
Grain Yield ◽  
Linear Regression Analysis ◽  
Sub Saharan Africa ◽  
International Institute ◽  
Breeding Programs ◽  
Genetic Gains ◽  
Rainfed Conditions ◽  
Early Maturing ◽  
Selection For ◽  
Sub Saharan

Genetic gain studies in a breeding program are very important for measuring the efficiency of the program over a specific period. It also provides breeders with an understanding of the outcomes of the huge investments committed to the breeding programs. This study sought to (i) estimate the gains in grain yield under drought and rainfed conditions and (ii) identify high-yielding and stable hybrids developed in the last two decades under drought and rainfed conditions. Sixty extra-early maturing hybrids developed by the International Institute of Tropical Agriculture (IITA), Ibadan, during three breeding periods: (2008–2010, 2011–2013, and 2014–2016) were assessed under managed drought and rainfed conditions across 14 environments in Nigeria to estimate the genetic gains in grain yield using linear regression analysis. Considerably high genetic gains (4.1%) per year for grain yield was obtained for the extra-early maturing hybrids under drought environments. Six of the top ten hybrids identified were from period 3, an indication of the high genetic gains from selection in period 3. Additionally, two of the top six period 3 hybrids (TZEEI 29 × TZEEI 13) × TZEEI 64 and TZdEEI 64 × TZEEI 54 were found to be the best yielding and most stable across the 14 test environments and were highly recommended for extensive evaluations to warrant their commercialization in sub-Saharan Africa (SSA).

scholarly journals Combining Ability of Early-Maturing Yellow Maize Inbreds under Combined Drought and Heat Stress and Well-Watered Environments

Agronomy ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1585
Author(s):  
Laouali M. Nasser ◽  
Baffour Badu-Apraku ◽  
Vernon E. Gracen ◽  
Hortense N. A. Mafouasson
Keyword(s):  
Heat Stress ◽  
Grain Yield ◽  
Combining Ability ◽  
Selection Index ◽  
Climatic Conditions ◽  
Sub Saharan Africa ◽  
Yield Potential ◽  
Early Maturing ◽  
Maize Inbreds ◽  
Drought And Heat Stress

Grain-yield potential of maize (Zea mays L.) is limited by the harsh climatic conditions during dry seasons in the savanna of sub-Saharan Africa (SSA). One hundred and five hybrids derived from diallel crosses involving 15 early-maturing yellow maize inbreds were screened under combined drought and heat stress (CDHS) and well-watered (WW) conditions at four locations representative of the dry savannas of Niger, 2012–2014. The objective of the study was to examine the general combining ability (GCA) effects of the inbred lines and specific combining ability (SCA) of the crosses under CDHS and WW environments, assess yield and stability of the derived hybrids under contrasting environments and investigate inter-relationships among traits of the hybrids under contrasting environments. GCA and SCA effects for grain yield and other measured traits were significant, with preponderance of GCA effects over SCA effects under both the CDHS and WW environments. Inbred ENT 13 possessed positive and significant GCA effects for grain yield under both CDHS and WW environments indicating that the inbred could be used for developing outstanding hybrids with good levels of tolerance to CDHS. This also implied that the inbred line could serve as invaluable genetic resource for introgression of favorable alleles into tropical early-maturing maize populations for accelerated genetic gains from selection for improved grain yield. Hybrids ENT 13 × TZEI 167 and TZEI 157 × ENT 13 were the most stable and among the highest yielding hybrids across research environments. These outstanding hybrids could be tested extensively for commercialization in SSA to improve food security. Plant and ear aspects and days to 50% silking could be combined with grain yield in a selection index for improvement of yield under CDHS without yield penalties under WW environments.

scholarly journals Genetic Gains in Pearl Millet in India: Insights Into Historic Breeding Strategies and Future Perspective

2021 ◽  
Vol 12 ◽  
Author(s):  
Om Parkash Yadav ◽  
S. K. Gupta ◽  
Mahalingam Govindaraj ◽  
Rajan Sharma ◽  
Rajeev K. Varshney ◽  
...  
Keyword(s):  
Pearl Millet ◽  
Pennisetum Glaucum ◽  
Sub Saharan Africa ◽  
Hybrid Breeding ◽  
Future Perspective ◽  
Yield Increase ◽  
Genetic Gains ◽  
Parental Lines ◽  
Sub Saharan ◽  
Periodic Replacement

Pearl millet (Pennisetum glaucum R. Br.) is an important staple and nutritious food crop in the semiarid and arid ecologies of South Asia (SA) and Sub-Saharan Africa (SSA). In view of climate change, depleting water resources, and widespread malnutrition, there is a need to accelerate the rate of genetic gains in pearl millet productivity. This review discusses past strategies and future approaches to accelerate genetic gains to meet future demand. Pearl millet breeding in India has historically evolved very comprehensively from open-pollinated varieties development to hybrid breeding. Availability of stable cytoplasmic male sterility system with adequate restorers and strategic use of genetic resources from India and SSA laid the strong foundation of hybrid breeding. Genetic and cytoplasmic diversification of hybrid parental lines, periodic replacement of hybrids, and breeding disease-resistant and stress-tolerant cultivars have been areas of very high priority. As a result, an annual yield increase of 4% has been realized in the last three decades. There is considerable scope to further accelerate the efforts on hybrid breeding for drought-prone areas in SA and SSA. Heterotic grouping of hybrid parental lines is essential to sustain long-term genetic gains. Time is now ripe for mainstreaming of the nutritional traits improvement in pearl millet breeding programs. New opportunities are emerging to improve the efficiency and precision of breeding. Development and application of high-throughput genomic tools, speed breeding, and precision phenotyping protocols need to be intensified to exploit a huge wealth of native genetic variation available in pearl millet to accelerate the genetic gains.

scholarly journals Testcross performance and combining ability of early maturing maize inbreds under multiple-stress environments

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Benjamin Annor ◽  
Baffour Badu-Apraku ◽  
Daniel Nyadanu ◽  
Richard Akromah ◽  
Morakinyo A. B. Fakorede
Keyword(s):  
Grain Yield ◽  
Combining Ability ◽  
Central Africa ◽  
Optimal Conditions ◽  
Gene Effects ◽  
Maize Production ◽  
Multiple Stress ◽  
Early Maturing ◽  
Additive Gene ◽  
West And Central Africa

Abstract Availability of multiple-stress tolerant maize is critical for improvement in maize production in West and Central Africa (WCA). A study was carried out to (i) assess a set of inbred lines for combining ability under stressed and optimal conditions, (ii) determine the performance of the testcrosses under different conditions, and (iii) identify outstanding hybrids across the conditions. Two hundred and five testcrosses were planted with five hybrid checks under Striga-infested, low soil nitrogen, drought and optimal conditions between 2015 and 2016 in Nigeria. The grain yield inheritance under optimal condition was largely regulated by additive gene effect whereas non-additive gene effects largely regulated grain yield under the three stresses. Four of the inbreds had significant positive general combining ability effects each under low N and drought, and three under Striga infestation for grain yield. The inbreds could be vital sources of beneficial alleles for development and improvement of tropical yellow maize hybrids and populations. Hybrids TZEI 443 x ENT 13 and TZEI 462 x TZEI 10 were high yielding and stable; they out-performed the three early maturing released hybrids in WCA. The new hybrids should be extensively assessed and released in the sub-region to improve food security.

COMBINING ABILITY ANALYSIS OF DROUGHT TOLERANCE IN WHEAT OVER DIFFERENT WATER REGIMES

2001 ◽  
Vol 48 (4) ◽  
pp. 353-361 ◽  
Author(s):  
E. Farshadfar ◽  
M. Farshadfar ◽  
J. Sutka
Keyword(s):  
Chlorophyll Fluorescence ◽  
Drought Tolerance ◽  
Grain Yield ◽  
Combining Ability ◽  
Relative Water Content ◽  
Harvest Index ◽  
Environment Interaction ◽  
Combining Ability Analysis ◽  
Rainfed Conditions ◽  
Relative Water

To study the properties of some drought tolerance criteria and  agronomic characters in wheat, an eight-parental diallel cross, excluding reciprocals, was grown in a randomized complete block design with three replications under two different water regimes (irrigated and rainfed) for two years in the College of Agriculture at Razi University, Kermanshah, Iran. High broad-sense heritability estimates were observed for harvest index, grain yield, and earliness. Additive gene action was found to be predominant for grain yield, harvest index, relative water content and chlorophyll fluorescence. The results of combining ability analysis revealed that Plainsman was the best general combiner and Plainsman × Kobomugi was the best specific combination for improving drought tolerance. The pooled analysis of variance for combining ability over rainfed conditions reflected that the GCA × environment interaction was not significant for harvest index and chlorophyll fluorescence, and the SCA × environment interaction was  non-significant for relative water content and relative water loss, indicating that genes controlling osmoregulation and the other physiological traits mentioned are not affected in these varieties by different rainfed conditions and hence show static stability.

scholarly journals Evaluating Performance of Sesame (Sesamum indicumL.) Genotypes in Different Growing Seasons in Northern Ethiopia

2019 ◽  
Vol 2019 ◽  
pp. 1-7 ◽  
Author(s):  
Fiseha Baraki ◽  
Muez Berhe
Keyword(s):  
Grain Yield ◽  
Seed Weight ◽  
Agronomic Traits ◽  
Block Design ◽  
Sub Saharan Africa ◽  
Northern Ethiopia ◽  
Growing Seasons ◽  
Randomized Complete Block Design ◽  
Sub Saharan ◽  
Thousand Seed Weight

Ethiopia is one of the famous and major producers of sesame in sub-Saharan Africa, and Ethiopian sesame is among the highest quality in the world. The experiment was conducted in Northern Ethiopia for three growing seasons (2013–2015) under a rain fed condition with the objective of identifying high-yielding genotypes and their agronomic traits. The experiment consisted of twelve genotypes laid down in randomized complete block design with three replications. The genotype, year, and genotype × year interaction components showed statistically highly significant variation (p<0.001) for most of the agronomic traits which clearly confirms the presence of genotype × year interaction in this study. The highest combined mean grain yield (906.3 kg/ha) was obtained from Hirhir followed by Serkamo white (756.5 kg/ha), and from the three growing seasons, the highest grain yield (1161.5 kg/ha) was recorded from Hirhir grown in the second growing season (2014). The growing seasons were different from one another in allowing the genotypes to have a different performance, and all of the agronomic traits, except thousand seed weight, were statistically different across the three growing seasons. In the ordination of the genotypes and agronomic traits, PCA1, which accounted for 38.3% of the variation, was positively associated with grain yield, branches per plant, length of the pod-bearing zone, plant height, number of pods per plant, number of seeds per pod, and thousand seed weight. On the contrary, PCA2, which accounted for 19.7% of the variation, was positively associated with days to 50% flowering and days to 50% maturity.

scholarly journals Analysis of Combining Ability in Rice Varieties for Quantitative Traits

2019 ◽  
Vol 11 (3) ◽  
pp. 436-439
Author(s):  
Ghaffar KIANI
Keyword(s):  
Grain Yield ◽  
Combining Ability ◽  
Agronomic Traits ◽  
Block Design ◽  
Rice Varieties ◽  
Gene Effects ◽  
Breeding Programs ◽  
Grain Length ◽  
Additive Gene Effects ◽  
Additive Gene

Rice is staple food in Iran. Despite of high quality of local rice, their grain yield is low. In hybridization breeding programs, selection of suitable parents is an essential role for developing new combinations with broadens genetic diversity. Combining ability of local rice varieties namely ‘Hashemi’, ‘Sang Jo’ and ‘Tarom Deylamani’ and ‘Nemat’ was evaluated in a partial diallele analysis for agronomic traits in a randomized complete block design at Sari Agricultural Sciences and Natural Resources University. General combining ability (GCA) and specific combining ability (SCA) variances showed predominated role of additive gene effects in the inheritance of grain length. Both additive and non-additive components of genetic variances were important in the inheritance of traits like grain yield, plant height, panicle length, total grains per panicle, grain length and grain length to width. However, non-additive gene effects were seen for tiller number. Results showed that ‘Nemat’ was the best general combiner for most of characters followed by ‘Tarom Deylamani’. The cross of ‘Hashemi’ × ‘Tarom Deylamani’ was suggested to exploitation of heterosis breeding for increasing yield and its components in rice breeding programs. 

scholarly journals Evaluating the performance of some Primitive Wheat Triticum dicoccum Genotypes

Food Biology ◽  
1970 ◽  
pp. 23-27
Author(s):  
Maysoun M. Saleh ◽  
Dyab S. Moussa ◽  
Nader I. Alkaraki ◽  
Abbas Lateef Abdurahman
Keyword(s):  
Grain Yield ◽  
Yield Components ◽  
Growing Season ◽  
Grain Weight ◽  
Individual Plant ◽  
Thousand Grain Weight ◽  
Breeding Programs ◽  
Triticum Dicoccum ◽  
Rainfed Conditions ◽  
Superior Genotypes

Seven wheat genotypes (Triticum dicoccum) and the local check sham5 variety were planted during  growing season 2010/2011under rainfed conditions using RCBD with three replications. Yield components (number of total and fertile tillers, number and weight of grains per spike, weight of thousand grain and individual plant grain yield) were studied in two sites in order to define the differences between the studied genotypes in both sites and to provide the superior genotypes for breeding programs. Results showed that the genotype PW70 was significantly superior in (grain yield, number and weight of grain per spike) comparing to check. While, the genotypes (PW96, PW119, PW123) were significantly superior in thousand grain weight comparing to check, as well as the genotype (PW81, PW127) were significantly superior in total and fertile tillers number comparing to check. Most traits were significantly superior in Al-Ghab site.

scholarly journals Efficiencies of Heterotic Grouping Methods for Classifying Early Maturing Maize Inbred Lines

Agronomy ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1198
Author(s):  
Oyeboade Adebiyi Oyetunde ◽  
Baffour Badu-Apraku ◽  
Omolayo Johnson Ariyo ◽  
Christopher Olusanya Alake
Keyword(s):  
Grain Yield ◽  
Genetic Distance ◽  
Combining Ability ◽  
Diallel Cross ◽  
Hybrid Breeding ◽  
Multiple Traits ◽  
Heterotic Groups ◽  
Maize Hybrids ◽  
Heterotic Grouping ◽  
Additive Gene

The success of a hybrid breeding program is dependent on available heterotic patterns for exploitation of grain-yield heterosis. The efficiency of the assignment of germplasm lines into heterotic groups is a prerequisite for obtaining useful heterotic patterns among germplasm lines. A total of 256 maize hybrids, comprising 244 top crosses, six diallel cross hybrids, and six checks, were grown under Striga infestation, drought, and optimal conditions, from 2015 to 2017. The study determined the combining abilities of the parental inbreds, classified the inbreds into heterotic groups, and compared the efficiencies of the following four grouping methods for classifying the inbreds: specific combining ability (SCA) effect of grain yield; general combining ability (GCA) effects of multiple traits (HGCAMT); SCA and GCA (HSGCA) for yield; and single nucleotide polymorphism-based genetic distance (SNP-based genetic distance (GD)). Significant GCA and/or SCA mean squares were revealed for most measured traits in all test environments. Sums of squares (SS) due to GCA were higher than SCA SS for measured traits in all test environments. The HSGCA, SCA, and SNP-based GD methods identified four heterotic groups, whereas the HGCAMT identified three groups, in all environments. The additive gene effect was preponderant in the inheritance of most measured traits. The efficiencies of the grouping methods varied with the test environments. The HSGCA and SCA methods were the most efficient for grouping in all test conditions. For practical breeding purposes, the HGCAMT and HSGCA methods were recommended under Striga infestation and drought, respectively. The heterotic patterns, which were revealed in this study, were effective for planning hybridization schemes for developing high-yielding, Striga-tolerant/resistant, and drought-tolerant maize hybrids for stressful environments.

scholarly journals Combining Ability and Gene Action of Tropical Maize (Zea mays L.) Inbred Lines under Low and High Nitrogen Conditions

2017 ◽  
Vol 9 (4) ◽  
pp. 222 ◽  
Author(s):  
Mafouasson Apala Hortense Noëlle ◽  
Kenga Richard ◽  
Gracen Vernon ◽  
Yeboah Agyei Martin ◽  
Mahamane Nasser Laouali ◽  
...  
Keyword(s):  
Grain Yield ◽  
Soil Nitrogen ◽  
Combining Ability ◽  
Gene Action ◽  
Inbred Lines ◽  
Hybrid Breeding ◽  
Gene Effect ◽  
Single Cross ◽  
Additive Gene ◽  
Nitrogen Conditions

This study was conducted to determine combining ability and gene action in elite maize inbred lines under low and high soil nitrogen conditions for hybrid breeding. Forty two tropical inbred lines (three testers and 39 lines) were crossed using line × tester mating design. The resulting 117 F1 hybrids, along with 4 hybrids used as checks, were evaluated using an 11 × 11 lattice design with two replications for grain yield and yield related traits during the 2012 and 2013 cropping seasons at two sites (Mbalmayo and Nkolbisson). Results revealed predominant additive gene effect under high soil nitrogen (N) conditions. Non-additive gene effect influenced grain yield under low soil and thus could be exploited for hybrid development. Under high N conditions inbred lines CLYN246, J16-1, CLWN201, TL-11-A-1642-5, CLQRCWQ26 and 1368 were good general combiners. Lines CML 343, ATP S6 20-Y-1, CLWN201, 1368, ATP S9 30 Y-1 and CLQRCWQ26 were good general combiners for grain yield under low N. They could be used to develop low N tolerant varieties. Different single cross hybrid combinations were identified for high grain yields under both low and high N conditions. The selected lines and single cross hybrids are a useful source of valuable genetic material for future maize hybrid breeding or direct production under low N.

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