Rediscovering ‘Mexican June’: a nearly extinct landrace maize (Zea mays L.) variety

Abstract

‘Mexican June’ was a popular white, open-pollinated maize variety grown in the southwestern and southern USA. It was well adapted to both semi-arid and humid, hot environments and it was utilized for forage and grain. Its production waned with the maize hybrid revolution of the 1930s and 1940s—even though it was proven to outperform the new hybrids in hot, dry climates of the Southwest. The rising popularity of locally grown heirloom crops has increased interest in landrace varieties. There is also increasing focus on desert-adapted crop genetic resources as the need for more climate resilient crops is recognized. We tested the yield performance of six accessions of ‘Mexican June’ in comparison with organic certified commercial hybrids in southern New Mexico. We also documented several plant and ear traits to distinguish variation across the accessions. Several accessions yielded at or near commercial hybrid levels, attesting to the adaptation of ‘Mexican June’ to hot, semi-arid environments. This finding demonstrates that ‘Mexican June’ may prove useful in non-GMO production systems, and as a genetic resource for the improvement of abiotic stress tolerance in new, more resilient varieties. Variation in plant, ear, and kernel traits between accessions of ‘Mexican June’ was consistent with the hypothesis that there is not a single variety of ‘Mexican June’, but multiple varieties that form a complex.