Effect of genotype x environment interactions in popcorn maize yield and grain quality

Fourteen commercial popcorn maize hybrids were evaluated in a randomised block design in three locations for two years with the aim of introducing this crop into a region of the Buenos Aires province, Argentina, an area characterized by changing environmental conditions. The traits evaluated were grain yield, expansion volume, kernel width, kernel length, caryopsis roundness index, ear diameter, ear length, kernel density before expansion, expanded kernel density and prolificacy index. The interaction genotype x environment revealed environments favourable towards yield but which were simultaneously unfavourable towards expansion capacity, as well as genotypes stable for one of these variables but unstable for the other. However, some environments and genotypes were simultaneously favourable to both. Only a weak negative correlation was found between grain yield and expansion capacity, suggesting this relationship may not be very strong in these modern hybrids. Rounded grains showed higher expansion capacities, but this characteristic was negatively correlated to yield; roundness is therefore not recommended as a selection criterion. The prolificacy index correlated positively with yield but not with expansion volume, and is therefore a potential selection criterion.