Development and Release of Two Mid-Late Maturing Maize Hybrids for the Highland Agro-Ecologies of Uganda

Abstract

The maize yield in the highland areas of Uganda (1500 to 3000 masl), rarely exceeding 2 t ha^-1. The use of unimproved maize genotypes, the prevalence of pests and diseases, and low levels of input use has tremendously contributed to the low grain yields.  Accordingly, we obtained 100 maize inbred lines majorly from CIMMYT in the year 2013. The inbred lines were evaluated for adaptability and those selected were intercrossed to generate 80 single cross hybrids by January 2015. The 80 single cross hybrids were evaluated in preliminary yield trials in three sites namely, Kachwekano, Kalengyere and Buginyanya in 2015a season. The best combiners were crossed with the selected males to obtain 122 three-way cross hybrids. These were evaluated for adaptability in advanced yield trials in 2016a in Kachwekano, Kalengyere and Bukwo, from where the best five hybrids (BH33, BH31, BH27, BH104 and BH38) were selected for National Performance Trials (NPT)  in 2016b and 2017a seasons in Bukwo, Buginyanya, Zombo, Fort portal and Kalengere. Two candidate varieties namely BH31 and BH33 exhibited good agronomic qualities such as earlier maturity, tolerance to MLN and other diseases. The selected hybrids yielded 8.2 t ha^-1 and 7.2 t ha^-1 for BH31 and BH33, respectively. The two varieties are appropriate for cultivation in major highland and transitional maize growing regions in Uganda and were subsequently released as NAROMAIZE 731 and NAROMAIZE 733, respectively. The newly released varieties are expected to reduce the highland maize cropping season from over six months to five months.