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Maize (Zea mays L.) is an important staple food crop in West and Central Africa (WCA). However, its production is constrained by drought. Knowledge and understanding of the genetics of hybrid performance under drought is invaluable in designing breeding strategies for improving maize yield. One hundred and fifty hybrids obtained by crossing 30 inbreds in sets using the North Carolina Design II plus six checks were evaluated under drought and well‐watered conditions for 2 years at three locations in Nigeria. The objectives of the studies were to (i) determine the mode of gene action controlling grain yield and other important agronomic traits of selected early inbred lines, (ii) examine the relationship between per se performance of inbreds and their hybrids and (iii) identify appropriate testers for maize breeding programmes in WCA. General combining ability (GCA) and specific combining ability (SCA) mean squares were significant (P < 0.01) for grain yield and other traits under the research environments. The GCA accounted for 64.5 % and 62.3 % of the total variation for grain yield under drought and well‐watered conditions, indicating that additive gene action largely controlled the inheritance of grain yield of the hybrids. Narrow‐sense heritability was 67 % for grain yield under drought and 49 % under well‐watered conditions. The correlations between traits of early‐maturing parental lines and their hybrids were significant (P < 0.01) under drought, well‐watered and across environments. Mid‐parent and better‐parent heterosis for grain yield were 45.3 % and 18.4 % under drought stress and 111.9 % and 102.6 % under well‐watered conditions. Inbreds TZEI 31, TZEI 17, TZEI 129 and TZEI 157 were identified as the best testers. Drought‐tolerant hybrids with superior performance under stress and non‐stress conditions could be obtained through the accumulation of favourable alleles for drought tolerance in both parental lines. 相似文献
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B. Badu-Apraku M. Oyekunle M. A. B. Fakorede I. Vroh R. O Akinwale M. Aderounmu 《Euphytica》2013,192(3):413-433
Information on the combining ability, heterotic patterns and genetic diversity of maize (Zea mays L.) inbreds is crucial for the success of a hybrid program targeting the stress environments of West Africa (WA). Studies were conducted in 2011 at four locations in Nigeria to (i) determine the combining ability of 20 extra-early yellow inbred lines, (ii) classify the inbred lines into heterotic groups, and (iii) determine the genetic diversity among the lines. General combining ability (GCA) effects were greater than specific combining ability (SCA) effects across test environments suggesting that additive gene action was more important than the nonadditive in the set of inbred lines. The lines were classified into four heterotic groups based on SCA effects, and three groups based on heterotic groups’ specific and GCA, the GCA effects of multiple traits of inbred lines and molecular markers. TZEEI 79, TZEEI 67, and TZEEI 81 were the best inbred testers while TZEEI 95 × TZEEI 79 was the best single-cross tester. TZEEI 88 × TZEEI 66 and TZEEI 96 × TZEEI 73 were identified as ideal hybrids for further testing, promotion for adoption and commercialization in WA. 相似文献
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Lucky O. Omoigui Alpha Y. Kamara Hakeem A. Ajeigbe Richard O. Akinwale Michael P. Timko Muhyideen Oyekunle Lateef L. Bello 《Euphytica》2017,213(11):244
Striga gesnerioides (Willd) Vatke, is a major destructive parasitic weed of cowpea (Vigna unguiculata (L.) Walp.) which causes substantial yield reduction in West and Central Africa. The presence of different virulent races within the parasite population contributes to significant genotype × environment interaction, and complicates breeding for durable resistance to Striga. A 3-year study was conducted at three locations in the dry savanna agro-ecology of Nigeria, where Striga gesnerioides is endemic. The primary objective of the study was to identify cowpea genotypes with high yield under Striga infestation and yield stability across test environments and to access suitability of the test environment. Data collected on grain yield and yield components were subjected to analysis of variance (ANOVA). Means from ANOVA were subjected to the genotype main effect plus genotype × environment (GGE) biplot analysis to examine the multi-environment trial data and rank genotypes according to the environments. Genotypes, environment, and genotypes × environment interaction mean squares were significant for grain yield and yield components, and number of emerged Striga plants. The environment accounted for 35.01%, whereas the genotype × environment interaction accounted for 9.10% of the variation in grain yield. The GGE biplot identified UAM09 1046-6-1 (V7), and UAM09 1046-6-2 (V8), as ideal genotypes suggesting that these genotypes performed relatively well in all study environments and could be regarded as adapted to a wide range of locations. Tilla was the most repeatable and ideal location for selecting widely adapted genotypes for resistance to S. gesnerioides. 相似文献
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Omoshaba E. O. Ojo O. E. Oyekunle M. A. Sonibare A. O. Adebayo A. O. 《Tropical animal health and production》2020,52(5):2599-2608
Tropical Animal Health and Production - Methicillin-resistant Staphylococcus aureus (MRSA), an important widespread cause of severe infection in both humans and animals, is a significant pathogen... 相似文献
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Assessment of maize (Zea mays L.) hybrids for adaptation to diverse environments is crucial for sustainability of maize production and productivity in sub-Saharan Africa. A total of 110 hybrids derived from 10 elite drought-tolerant maize inbreds and 11 checks were evaluated at three locations for 2 years in Nigeria to identify high-yielding and stable hybrids using different stability approaches. Mean squares were significant for genotypes (G), environments (E) and genotype x environment interaction (GEI) for grain yield and most other traits. The test environments contributed 83.7% to the total variation in grain yield, whereas G accounted for 5.0% and GEI 11.3%. The repeatability of traits ranged from 0.22 to 0.66. Grain yield of hybrids ranged from 2.1 t ha?1 for TZEI 17 × TZEI 16 to 4.1 t ha?1 for TZEI 129 × TZEI 16, with mean yield of 3.1 t ha?1. The results of additive main effect and multiplicative interaction (AMMI) analysis and rank summation index were found to be consistent, as both methods identified TZEI 129 × TZEI 16 and (TZEI 17 × TZEI 16) × TZEI 157 as high-yielding and consistent-performing across test environments. The outstanding hybrids should be further tested on-farm to facilitate the registration and commercialization in Nigeria. 相似文献
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A base index involving Striga damage, number of emerged Striga plants and ears per plant is used for selecting for maize (Zea mays L.) grain yield under Striga infestation. There are contradictory reports on the reliability of number of emerged Striga plants for selecting for Striga resistance. The objective of this study was to confirm reliability of the secondary traits for selecting for improved grain yield under Striga infestation. Ten Striga‐resistant extra‐early cultivars were evaluated for 3 years under artificial Striga‐infested and Striga‐free environments in Nigeria. Analysis of variance combined across years and locations showed significant mean squares for genotype, year, location and their interactions for most traits. Sequential path analysis identified ear aspect as the only trait with significant direct effect on yield under artificial Striga infestation, while GGE biplot confirmed ear aspect, ears per plant and Striga damage as the most reliable traits. Ear aspect should be included in the base index for selecting for improved grain yield of extra‐early maize under Striga infestation, while the number of emerged Striga plants should be excluded. 相似文献
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