Enhancing adaptation of tropical maize to temperate environments using genomic selection

Area of Science:

• Plant breeding
• Genetics
• Agricultural science

Background:

• Tropical maize offers valuable genetic diversity for temperate climate-adapted cultivars.
• Tropical maize exhibits maladaptive traits in temperate zones, including delayed flowering and low yield, due to photoperiod and temperature sensitivities.

Purpose of the Study:

• To evaluate the efficacy of genomic selection in an off-season nursery to accelerate the adaptation of tropical maize for temperate environments.
• To determine if genomic selection can improve genetic gains for flowering time more efficiently than traditional phenotypic selection.

Main Methods:

• Genomic prediction models were trained using flowering time data from tropical maize populations grown at two northern U.S. latitudes.
• Phenotypic selection and model training were conducted within target environments and lineages.
• Genomic prediction of intermated progenies was performed in an off-season nursery, with model performance evaluated on subsequent summer-grown progenies.

Main Results:

• Prediction abilities for flowering time ranged from 0.30 to 0.40 across populations and environments.
• Model accuracy was consistent across variations in marker effect distributions and spatial field effects.
• Genomic selection in a single off-season generation increased genetic gains for flowering time by over 50% compared to summer selection alone.

Conclusions:

• Genomic selection in an off-season nursery significantly accelerates the adaptation of tropical maize to temperate climates.
• This approach can reduce the time needed to achieve desired flowering times by one-third to one-half.
• Genomic selection is a powerful tool for enhancing genetic gains and shortening breeding cycles in climate adaptation efforts.