Early-Stage Phenotypic Variation and NaCl Tolerance in Native Mexican Maize Accessions

Area of Science:

• Plant Science
• Agronomy
• Genetics

Background:

• Salinity poses a significant challenge to maize (Zea mays L.) establishment.
• Early-stage salinity tolerance in native Mexican maize accessions is not well understood.

Purpose of the Study:

• To evaluate the in vitro response of 130 native Mexican maize accessions to saline stress.
• To identify maize germplasm with enhanced early-stage salinity tolerance.

Main Methods:

• Germination assays under control and saline (150 mM NaCl) conditions.
• Measurement of early seedling traits: germination, coleoptile/mesocotyl/radicle length, seminal root number, and biomass.
• Multivariate analyses (PCA, hierarchical clustering) to classify phenotypic responses.

Main Results:

• Salinity significantly impacted germination and seedling growth, with notable variation among accessions.
• Accessions CIMMYT 433 and CIMMYT 658 demonstrated superior traits for salinity tolerance.
• Four distinct response groups were identified, highlighting differential tolerance levels.

Conclusions:

• Native Mexican maize possesses considerable genetic variation for early-stage salinity tolerance.
• Multivariate analysis effectively categorizes maize accessions based on salinity response.
• Identified accessions are valuable resources for maize breeding programs focused on salinity tolerance.