Grappling with a rice shortage after extreme weather ravaged last year's crop, Japan is hoping new heat-resistant varieties of its staple food can help stave off future supply shocks.

Last summer's high temperatures and dry conditions led to lower rice yields in key growing regions and damaged the quality of grains, contributing to the lowest inventories seen in 25 years, according to official data.

Along with higher demand — partly attributed to record inbound tourism this year — supermarkets across the country have struggled to keep rice shelves stocked in recent months and some have imposed quotas on how much customers can buy.