Genetic gains from selection for high grain yield and Striga resistance in early maturing maize cultivars of three breeding periods under Striga-infested and Striga-free environments

Title 
Genetic gains from selection for high grain yield and Striga resistance in early maturing maize cultivars of three breeding periods under Striga-infested and Striga-free environments 
Publication Type 
Journal Article 
Authors 
Badu-Apraku B, Yallou CG, Oyekunle M 
Year of Publication 
2013 
Volume 
147 
Journal 
Field Crops Research 
Pagination 
54 - 67 
Date Published 
6/2013 
ISSN 
03784290 
Keywords 
Breeding periods, Genetic gain, Maize, Striga hermonthica, Striga resistance/tolerance 
URL 
http://www.sciencedirect.com/science/article/pii/S0378429013001159 
DOI 
10.1016/j.fcr.2013.03.022 
Abstract 

Maize is the most important staple cereal crop in sub-Saharan Africa (SSA) and has great potential to rectify the food insecurity in the sub-region. A study was conducted at four locations two each in Nigeria and Benin in 2010 and 2011 to determine the rate of genetic improvement in the grain yield of 50 maize cultivars developed during three breeding periods, 1988–2000 (period 1), 2001–2006 (period 2) and 2007–2010 (period 2) under Striga-infested and Striga-free conditions. Under Striga infestation, mean grain yield ranged from 2537 kg ha−1 for the period 1 cultivars to 3122 kg ha−1 for period 3 cultivars with a corresponding annual genetic gain of 1.93%. When Striga-free, grain yield ranged from 3646 kg ha−1 for the period 1 cultivars to 4227 kg ha−1 for the period 2 cultivars with an annual genetic gain of 1.0%. The average annual rate of increase in grain yield was 41 kg ha−1 when Striga-infested and 34 kg ha−1 when Striga-free. The annual genetic gain in grain yield was 0.86% for period 1 cultivars, 2.07% for period 2 cultivars, and 2.11% for period 3 cultivars under Striga infestation. The increase in grain yield under Striga infestation was associated with significant decrease in Striga damage and the number of emerged Striga plants at 8 and 10 weeks after planting (WAP), an improvement in ear aspect, lodging resistance, plant height, and increase in the number of ears per plant (EPP) from the period 1 to the period 3 cultivars. For the emerged Striga plants, the annual genetic gains of −0.63% for 8 WAP and −0.57% for 10 WAP were obtained from the period 1 to the period 2 cultivars. The increase in genetic gains was 0.70% for EPP and −0.65% for ear aspect. The increase in grain yield from period 1 to period 3 cultivars when Striga-free was associated with increased days to anthesis, increased plant and ear heights, improvement in ear aspect, and husk cover and increased EPP. Cultivars 28, 14, 29, and 26 were the most outstanding across Striga-infested environments. Substantial progress has been made in breeding for high yielding, Striga resistant/tolerant cultivars during the past three decades.

Highlights
  • Under Striga infestation, mean grain yield ranged from 2537 to 3122 kg ha−1 with a corresponding annual genetic gain of 1.93%.
  • When Striga-free, grain yield ranged from 3646 to 4227 kg ha−1 with an annual genetic gain of 1.0%.
  • Annual genetic gain in grain yield ranged from 0.86% for period 1 to 2.11% for period 3 cultivars under Striga infestation.
  • For the emerged Striga plants, the annual genetic gain was −0.63% for 8 WAP and −0.57% for 10 WAP for the breeding periods.
  • Cultivars 28, 14, 29, and 26 were the highest yielding and most stable across Striga-infested environments.
 
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