Survey of Mycorrhizal Colonization in Native, Open-Pollinated, and Introduced Hybrid Maize in Villages of Chiquimula, Guatemala

ABSTRACT

Replacing native plant types with introduced cultivars may have unexpected cropping system consequences. Native species and introduced cultivars may vary in their ability to form mycorrhizal symbioses with soil fungi and consequently affect phosphorus (P) nutrition. Low-input cropping systems often depend on mycorrhiza for adequate nutrition and growth, while high-input systems minimize the benefit of and need for colonization. Studies in wheat (Triticum aestivum L.) suggest that improving cultivars reduced the ability to form mycorrhiza. This study was conducted at six sites in the province of Chiquimula, Guatemala, to determine the difference in mycorrhizal infection rates between two maize (Zea mays L.) cultivars—‘Cushpeño,’ a native, open-pollinated variety, and ‘HB-83,’ an introduced, improved hybrid. The ‘HB-83’ was colonized at a significantly lower percentage (67%) than was ‘Cushpeño’ (72%; α = 0.0137). A strong negative correlation (r = −0.953) existed between Mehlich-3 extractable soil P and differences in mycorrhizal colonization rates between the two genotypes. The full impact of lower colonization rates of the introduced hybrid on sustainability of the village agricultural system needs further investigation.

Keywords:

• Maize cultivars
• mycorrhizal colonization
• P nutrition
• soil test P
• subsistence farming
• Zea mays

ACKNOWLEDGMENTS

The authors express gratitude to the Ezra Taft Benson Agriculture and Food Institute and its Guatemalan office for logistical and financial support. They also wish to thank the Centro Universitario del Oriente (CUNORI) for the use of soil and plant analysis facilities and technical help. Special appreciation is expressed to the Sant family for funding.