CIMMYT unveils three fall armyworm-tolerant maize varieties for Eastern and Southern Africa
23-12-2020 07:41:17 | by: Bob Koigi | hits: 6527 | Tags:

The International Maize and Wheat Improvement Center (CIMMYT) has announced the successful development of three CIMMYT-derived fall armyworm-tolerant elite maize hybrids for eastern and southern Africa.

Fall armyworm (Spodoptera frugiperda) emerged as a serious threat to maize production in Africa in 2016 before spreading to Asia in 2018. Host plant resistance is an important component of integrated pest management (IPM).

By leveraging tropical insect-resistant maize germplasm developed in Mexico, coupled with elite stress-resilient maize germplasm developed in sub-Saharan Africa, CIMMYT worked intensively over the past three years to identify and validate sources of native genetic resistance to fall armyworm in Africa. This included screening over 3,500 hybrids in 2018 and 2019.

Based on the results of on-station screenhouse trials for fall armyworm tolerance (under artificial infestation) conducted at Kiboko during 2017-2019, CIMMYT researchers evaluated in 2020 a set of eight test hybrids (four early-maturing and four intermediate-maturing) ) against four widely used commercial hybrids (two early- and two intermediate-maturing) as checks. The trials conducted were:

“No choice” trial under fall armyworm artificial infestation in screenhouses in Kiboko, Kenya: Each entry was planted in 40 rows in a separate screenhouse compartment (“no-choice”), and each plant infested with seven fall armyworm neonates 14 days after planting. Foliar damage was assessed 7, 14 and 21 days after infestation. Ear damage and percent ear damage were also recorded, in addition to grain yield and other agronomic parameters.

On-station trials in eastern Africa: The trials, including the eight test entries and four commercial checks, were conducted at six locations in Kenya during the maize cropping season in 2020. Entries were evaluated for their performance under managed drought stress, managed low nitrogen stress, and under artificial inoculation for Turcicum leaf blight (TLB) and Gray leaf spot (GLS) diseases. The three-way cross CIMMYT test hybrids and their parents were also characterized on-station for their seed producibility, including maximum flowering time difference between parents, and single-cross female parent seed yield.

The eight test entries with fall armyworm tolerance were also included in the regional on-station trials (comprising a total of 58 entries) evaluated at 28 locations in Kenya and Tanzania. The purpose of these regional trials was to collect data on agronomic performance.

On-farm trials in Kenya: The eight test hybrids and four commercial checks were evaluated under farmers’ management conditions (without any insecticide spray) at 16 on-farm sites in Kenya. Each entry was planted in 20-row plots, and data was recorded on natural fall armyworm infestation.

Foliar damage was assessed 7, 14, 21, 28 and 35 days after germination together with insect incidence. Ear damage and percent ear damage were also recorded, besides grain yield and other agronomic parameters.