Developing the next generation of diverse and healthier maize cultivars tolerant to climate changes

Abstract

Maize (Zea mays L.) average yields per hectare have significantly increased in the past 80 years. However, the variability of these yields across years has also significantly increased in the past 40 years making newer and genetically narrow-based hybrids, on average, less stable and more susceptible to climate changes. The objective of this research was to develop new sources of short-season inbred lines carrying unique alleles to grow maize hybrids under challenging environments. The North Dakota State University (NDSU) maize germplasm enhancement program has recently developed 10 new and unique exotic short-season populations partially derived from Argentina, Brazil, Chile, Cuba, Mexico, Saint Croix, and the USA. These germplasm sources were created recombining top early-generation NDSU EarlyGEM lines that were extensively tested in hybrid trials for general combining ability of several traits. Results have shown that germplasm carrying unique alleles can break environmental margins for maize production. Unfortunately, maize breeding programs tend to be located in ideal crop production areas instead of exploiting marginal environments for the development of more stable products. The NDSU EarlyGEM program is a successful example of tropical and late-temperate maize germplasm adaptation into short-season environments in order to increase the genetic diversity on farms. However, public sector applied maize breeding programs continue to disappear across the USA and abroad because of changes in research emphasis. Long-term germplasm adaptation and improvement programs carrying unique alleles will be essential in the development of the next generation of healthier cultivars tolerant to climate changes.