Manifestation of heterosis for fruit yield, quality and shelf-life in tomato (Solanum lycopersicum L.) hybrids incorporating rin, nor or alc alleles in main-and late-seasons of north Indian plains

Sixty F₁ hybrids of tomato developed by crossing 15 normally ripening lines with 4 mutant homozygotes were evaluated along with a standard check (TH-1) for 14 traits in two seasons to ascertain the extent of standard heterosis and to identify a few promising cross-combinations. Significant and desirable standard heterosis was observed for all the traits in both main and late-season. Not even a single hybrid exhibited significant and negative standard heterosis in any environment for total yield per plant, marketable yield per plant, average fruit weight and shelflife index. The standard heterosis up to 165.88 and 239.13% for total yield, 174.60 and 302.16% for marketable yield, 102.28 and 195.96% for number of fruits, 101.77 and 78.24% for average fruit weight, -43.33 and-33.67% for firmness index, 50.15 and 105.99% for number of locules, 71.51 and 126.47% for pericarp thickness, 29.69 and 38.97% for alcohol insoluble solids, 30.71 and 40.15% for lycopene, 70.61 and 33.84% for dry matter, 52.63 and 38.78% for total soluble solids, 40.98 and 45.10% for titratable acidity, 17.95 and 8.04% for ascorbic acid, 77.78 and 77.78% for shelf life was observed in main and late-season, respectively. The promising crosscombinations were Castle Rock x nor-RM-1, IPA-3 x nor-RM-1, Nemadoro x nor-RM-1 and UC-82-B x nor-RM-1 in main-season and LT-44 x alc-IIHR-2050, LT-42 x rin-RM-2, Punjab Upma x nor-RM-1, IPA-3 x nor-RM-1 and LT-44 x rin-RM-2 in late-season.