Gains in Maize Genetic Improvement in Eastern and Southern Africa: II. CIMMYT Open-Pollinated Variety Breeding Pipeline

By B. Masuka, Cosmos Magorokosho, M. Olsen, G. Atlin, M. Bänziger, K. Pixley, B. Vivek, M. Labuschagne, Rumbidzai Matemba-Mutasa, Juan Burgueño and 9 more. 2017

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Open-pollinated varieties (OPVs) still represent a significant proportion of the maize (Zea mays L.) seed system in many countries of sub- Saharan Africa. The International Maize and Wheat Improvement Centre (CIMMYT) has been breeding improved maize varieties for the stress-prone environments experienced by most smallholder farmers in eastern and southern Africa for over 30 yr. Hybrid breeding is now the major focus of the CIMMYT breeding pipeline. However, OPVs are generated within the hybrid pipeline. This is the first study to document genetic gain for maize grain yield under both optimal and stress (random and managed drought, low nitrogen [N], and maize streak virus [MSV]) conditions within the CIMMYT eastern and southern African OPV breeding pipeline. Genetic gain was estimated using the slope of the regression on the year of OPV release in regional trials over a 12-yr period (1999–2011). Open-pollinated varieties were separated into two maturity groups, early (<70 d to anthesis) and intermediate-late (>70 d to anthesis). Genetic gain in the early maturity group under optimal conditions, random drought, low N, and MSV was 109.9, 29.2, 84.8, and 192.9 kg ha−1 yr−1. In the intermediate-late maturity group, genetic gain under optimal conditions, random drought, low N, and MSV was 79.1, 42.3, 53.0 and 108.7 kg ha−1 yr−1. No significant yield gains were made under managed drought stress for both maturity groups. Our results show continued improvement in OPVs for both yield potential and stress tolerance.

Subfields: Agronomy and Crop Science, Genetics, Plant Science

View Paper: https://www.semanticscholar.org/paper/d6234c41d18dc2a1b7f899c0ac55296b10edcf2b

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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): “A companion paper looks at genetic gain in OPVs in ESA over the same period (Masuka et al., 2016).”
Translating High-Throughput Phenotyping into Genetic Gain (2018, background): “As the public sector breeding moves toward informal networks such as the proposed ‘European Consortium for Open Field Experimentation’ [8] and the Eastern and Southern African Maize Breeding Network [20,46], the need to improve and standardize environmental collection is further reinforced.”
Climate risk management and rural poverty reduction (2018, background): “Newer drought-tolerant maize cultivars consistently outperform commercial varieties under drought conditions in field trials (Masuka et al., 2017a, b; Setimela et al., 2017a, b).”