Breeding for improved abiotic stress tolerance in maize adapted to southern Africa

Title 
Breeding for improved abiotic stress tolerance in maize adapted to southern Africa 
Publication Type 
Journal Article 
Authors 
Bänziger M, Setimela PS, Hodson D, Vivek B 
Year of Publication 
2006 
Volume 
80 
Journal 
Agricultural Water Management 
Issue 
1-3 
Pagination 
212 - 224 
Date Published 
2/2006 
ISSN 
03783774 
URL 
http://www.sciencedirect.com/science/article/pii/S0378377405002994 ; http://pdn.sciencedirect.com/science?_ob=MiamiImageURL&_cid=271238&_user=835555&_pii=S0378377405002994&_check=y&_origin=article&_zone=toolbar&_coverDate=2006--24&view=c&originContentFami 
Keywords 
Abiotic stress tolerance, Breeding progress, Drough, G × E interaction, Maize 
DOI 
10.1016/j.agwat.2005.07.014 
Abstract 

The difficulty of choosing appropriate selection environments has restricted breeding progress for abiotic stress tolerance in highly variable target environments. Genotype-by-environment interactions in southern African maize growing environments result from factors related to maximum temperature, season rainfall, season length, within-season drought, subsoil pH and socio-economic factors that result in sub-optimal input application. In 1997, CIMMYT initiated a product-oriented breeding program targeted at improving maize for the drought-prone mid-altitudes of southern Africa. Maize varieties were selected in Zimbabwe using simultaneous selection in three types of environments, (i) recommended agronomic management/high rainfall conditions, (ii) low N stress, and (iii) managed drought. Between 2000 and 2002, 41 hybrids from this approach were compared with 42 released and pre-released hybrids produced by private seed companies in 36–65 trials across eastern and southern Africa. Average trial yields ranged from less than 1 t/ha to above 10 t/ha. Hybrids from CIMMYT's stress breeding program showed a consistent advantage over private company check hybrids at all yield levels. Selection differentials were largest between 2 and 5 t/ha and they became less significant at higher yield levels. An Eberhart–Russell stability analysis estimated a 40% yield advantage at the 1-t yield level which decreased to 2.5% at the 10-t yield level. We conclude that including selection under carefully managed high-priority abiotic stresses, including drought, in a breeding program and with adequate weighing can significantly increase maize yields in a highly variable drought-prone environment and particularly at lower yield levels.
 

 
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