Abstract
Smallholder maize farmers in Africa experience pre- and post-harvest production stresses either individually or in combination at different stages of the crop cycle. The maize weevil is among the major post-harvest storage pests. A strategy to address this problem is to develop and promote high yielding maize germplasm with resistance to multiple stresses. A study was conducted to: 1) assess yield and agronomic performance of testcross hybrids developed from early generation lines; and 2) assess the response of the testcross hybrids to infestation with Sitophilus zeamais. Fifty-eight drought-tolerant testcross hybrids were evaluated for agronomic performance and weevil resistance at four environments in Uganda in 2016. Hybrid G39 (L2/T2) had the best grain yield performance; it significantly out-performed the best check by 11.4% in all environments. Hybrid grain from field trials was subjected to Sitophilus zeamais infestation in a choice and no choice test under laboratory conditions. Hybrids G56 (L49/T2) and G58 (L51/T2) had the least weevil damage and were rated as resistant to Sitophilus zeamais. The numbers of damaged kernels, number of exit holes and ear aspect were positively correlated with the grain weight loss. The results suggest possibilities for simultaneous selection for high grain yield and storage insect pest resistance among drought-tolerant genotypes. Use of high-yielding and resistant maize hybrids to storage insect pest should be promoted for increased maize production and managing post-harvest losses due to the maize weevil in smallholder farming communities in Africa.
Highlights
In Sub-Saharan Africa (SSA), maize (Zea mays L.) is the most important staple crop among the five biggest crops that contribute more than 45% of total crop production value (OECD/FAO, 2018)
In the cur rent study, we reported modest broad-sense heritability (0.61–0.64) for days to anthesis (AD), ear aspect (EA) and husk cover (HC), suggesting that actual heritability estimates might be lower (Falconer and Mackay, 1996), which could lead to low genetic gain from selection for these traits in this germplasm
The study used early generation inbred lines under development in maize breeding program of NARO, Uganda and, crossed with common testers, we identified hybrids with higher grain yield and weevil resis tance than best commercial check
Summary
In Sub-Saharan Africa (SSA), maize (Zea mays L.) is the most important staple crop among the five biggest crops that contribute more than 45% of total crop production value (OECD/FAO, 2018). Maize is considered to be an important crop in eastern African, there is still a deficit in production of the staple due to low soil fertility, frequent droughts, and insect pest damage. Smallholder maize farmers in eastern Africa experience pre- and post-harvest production stresses either individually or in combination at different stages of the crop cycle. The maize production deficit is aggravated by overwhelming post-harvest losses. Most important economic quantifiable post-harvest losses occurs in the field (15%), during storage (15%–25%), and during processing (13%–20%) (Abass et al, 2014). Grain weevils (Sitophilus zea mais and S. granarius) and larger grain borers (Prostephanus truncatus) are responsible for the major losses (Abass et al, 2014)
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