Scientists call for new Striga-resistant and drought-tolerant genes in bi-parental maize populations
Scientists say that genomic selection is effective for yield improvement in bi-parental maize populations infested by Striga and drought. This conclusion was made in a study titled “Yield gains and associated changes in an early yellow bi-parental maize population following genomic selection for Striga resistance and drought tolerance.”
The study was carried out after a new bi-parental maize population, TZEI 17 x TZEI 11 with combined tolerance to drought and resistance to Striga, was developed by IITA.
Maize (Zea mays L.) is an important cereal crop in sub-Saharan Africa, and one of IITA’s mandate crops. It plays a crucial food and nutrition role and serves as feed and industrial crop in the subregion.
However, its production is limited by factors such as drought (a regular occurrence in most agroecologies of sub-Saharan Africa due to irregular rainfall patterns and climate change in the subregion) and the Striga hermonthica parasite, which threatens the livelihood of over 300 million people in the region.
Yield loss due to drought stress could be as high as 90%, while Striga accounts for an estimated loss of staple food crop valued at $7 billion yearly.
To determine yield gains and associated changes in early maturing yellow bi-parental maize populations, 200 test crosses were evaluated under drought, artificial Striga-infested, and optimal environments.
The results of the study show that yield gains of 498 kg/ha/cycle (16.9%/cycle) and 522 kg/ha/cycle (12.6%/cycle) were obtained under Striga-infested and optimal environments, respectively.
Some changes in early maturing yellow bi-parental maize populations are increased plant and ear heights, improved root lodging, and Striga resistance.
The study concludes with a call for new sources of genes for Striga resistance and drought tolerance because of low genetic variability of most traits in the population.
The article was published in Volume 19 of BMC Plant Biology Open access journal. Find the full article here: https://bmcplantbiol.biomedcentral.com/articles/10.1186/s12870-019-1740-z