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Relative importance of general combining ability and specific combining ability among tropical maize (Zea mays L.) inbreds under contrasting nitrogen environments

Author: Worku, M.
Author: Bänziger, M.
Author: Friesen, D.
Author: Schulte auf'm Erley
Author: Horst, W.J.
Author: Vivek, B.
Year: 2008
Abstract: Low-N stress is among the major abiotic stresses causing yield reductions in maize grown in the mid-altitude tropical environments of Africa. This study estimates the relative importance of general combining ability (GCA) and specific combining ability (SCA) in CIMMYT's tropical mid-altitude inbred lines under contrasting N environments. Six hundred and thirty five lines (S2-S7) were evaluated in different crossing designs (Diallels, North Carolina Design II and Line x Tester crosses). Results of experiments conducted under low and high N at the same site in adjacent fields with the same soil type within the same year and season from 1999-2003 were compared. The contribution of GCA to total genetic variation was higher than SCA for anthesis date, ear height and plant height under both high and low N levels. However, contribution of GCA was higher for grain yield only under high-N conditions. The average relative contribution of SCA, indicative of non-additive gene effects, to total genetic variation for grain yield under low-N accounted for 51% (average across all trials) but only for 36% under high-N. Pair-wise t-test for diallels and Design IIs showed significant difference (P<0.05) between the proportion of SCA sum of squares for grain yield under high and low N conditions. This implies that breeding strategies that increase grain yield under optimal (high N) conditions will not address the needs of a resource poor farmer producing maize under low N conditions, especially in sub-Saharan Africa. Targeted strategies that increase yield under low N conditions are thus required.
Format: PDF
Language: English
Publisher: Consiglio per la Ricerca e la sperimentazione in Agricoltura, Unità di Ricerca per la Valorizzazione qualitativa dei cereali
Copyright: CIMMYT manages Intellectual Assets as International Public Goods. The user is free to download, print, store and share this work. In case you want to translate or create any other derivative work and share or distribute such translation/derivative work, please contact indicating the work you want to use and the kind of use you intend; CIMMYT will contact you with the suitable license for that purpose.
Type: Article
Region: Global
Pages: 279-288
Issue: 03-abr
Volume: 53
Keywords: Diallel Cross
Keywords: GCA
Keywords: General Combining Ability
Keywords: Nitrogen Environments
Keywords: Nstress
Keywords: SCA
Keywords: Specific Combining Ability
Keywords: diallel
Keywords: GCA
Keywords: general combining ability
Keywords: Inbred lines
Keywords: Maize
Keywords: Nitrogen
Keywords: Environments
Keywords: specific combining ability
Keywords: zea mays L.
Publisher URI:
Country of Focus: AFRICA
Agrovoc: MAIZE
Agrovoc: ZEA MAYS
Journal: Maydica

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  • Maize
    Maize breeding, phytopathology, entomology, physiology, quality, and biotech

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