Analysis of softening in air- and ethylene-treated rin, nor and wild-type tomato fruit

Rin; ripening-inhibitor and nor; non-ripening are previously identified spontaneous mutations that affect the primary regulation of tomato fruit ripening. Mutations at these loci result in fruit that are either partially or completely inhibited in their ability to ripen. Internal and whole fruit firmness of air- and ethylene-treated wild-type fruit declined by 59–87%. Firmness of whole rin and nor fruit decreased slightly after 9 days of air-treatment and internal fruit firmness did not change. Ethylene-treated rin and nor whole fruit softened over 9 days, but substantially less than wild type. At harvest and after air or ethylene treatment, firmness was greater in nor than in rin fruit. Surprisingly, slices from ethylene-treated rin and nor fruit softened much more than whole fruit, and softening of slices was similar for fruit of rin and nor.