Efficiency of Managed‐Stress Screening of Elite Maize Hybrids under Drought and Low Nitrogen for Yield under Rainfed Conditions in Southern Africa

By V. S. Weber, A. Melchinger, Cosmos Magorokosho, D. Makumbi, M. Bänziger, G. Atlin. 2012

112 citations recorded by the source corpus.

Maize (Zea mays L.) yields in southern Africa are low, due largely to drought and low-N stress. Selection of stress-tolerant genotypes by CIMMYT is conducted indirectly under managed stress conditions, although the selection effi ciency of this approach is not known. A retrospective analysis of 704 elite hybrid trials conducted from 2001 to 2009 was used to determine the relative ability of optimal, low-N, and managed drought trials to predict performance under the conditions of random abiotic stress and low-N fertility usually faced by African farmers. Well-fertilized trials in the rainy season were categorized as having experienced random abiotic stress if mean yield was <3 t ha -1 and the yield-anthesis date correlation was <0.1; otherwise they were classed as optimal. High genetic correlations were estimated between random abiotic stress and low-N or optimal conditions. Heritability was highest under optimal conditions and lowest under random abiotic stress. Indirect selection under low-N and optimal conditions was more effi cient than direct selection under random abiotic stress or indirect selection under managed drought, especially for early maturing genotypes, but direct selection was most effi cient for predicting performance under low N. Elite maize hybrids tolerant to random abiotic stress can be most effi ciently selected under optimal and/or low-N conditions while low-N tolerant genotypes should be selected directly under low N.

Subfields: Agronomy and Crop Science, Plant Science

View Paper: https://www.semanticscholar.org/paper/a945ad52fbcf741650bdea7050ee14931321a023

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Citations in the corpus

Gains in Maize Genetic Improvement in Eastern and Southern Africa: I. CIMMYT Hybrid Breeding Pipeline (2017, background): “…and managed drought and low-N stress trials in ESA showed that the repeatability (H) of the managed stress trials in this study was lower than that of nonstress trials and that plot residual variance under abiotic stress was high (Weber et al., 2012; Cairns et al., 2013b; Das et al., 2016).”
Predicting the future of plant breeding: complementing empirical evaluation with genetic prediction (2014, background): “…genetic gain for important environmental components of the TPE that contribute to repeatable G E interactions (Fischer et al. 1989; Cooper et al. 1995, 1997, 2014; Campos et al. 2004, 2006; Kirigwi et al. 2004; Trethowan et al. 2005; Bänziger et al. 2006; Weber et al. 2012; Rebetzke et al. 2013).”
Identification of Drought, Heat, and Combined Drought and Heat Tolerant Donors in Maize (2013, background): “A recent combined analysis of the southern Africa regional trials of CIMMYT and partners also found plot residual variance to be much higher under managed stress relative to non-stress trials (Weber et al. 2012b).”