GRADING, PACKING AND STORAGE OF SEEDS

Seed:

“A seed of a commercial tomato cultivar is flattened ovoid, upto 5 mm long, 4 mm wide and 2mm deep, consisting principally of the embryo, endosperm and testa or seedcoat”.

SECTION THROUGH A MATURE TOMATO SEED

TYPES OF SEED WITH REFERENCE TO DESICCATION

ü                  Desiccation Intolerant Seed / Recalcitrants

                High moisture (23 – 61.5 %), Short lived

ü                  Desiccation Tolerant Seed (Orthodox)

                Low moisture, Long lived

PREPARING DESICCATION TOLERANT SEEDS FOR STORAGE

ü                  Preparation for dormancy during ripening            and drying by greatly slowing or ceasing                 most physiological processes

ü                  Conversion of food reserves from sugar to          more stable fats and starches

DRYING AND STORAGE OF DESICCATION TOLERANT SEED

ü  Slow drying in shady spots

ü                  Spread thin layer of seed in airy and dry                location or AC environment

ü                  Relative humidity (20 – 40 %)

ü                  Temperature (28 – 30 C°)

ü                  Duration of drying (2 weeks)

USE OF SILICA GEL FOR FINAL DRYING

ü                  Use equal quantity of silica gel and seed in a       well sealed jar for 7 – 8 days

ü                  Transfer the dried seed quickly into an air            tight storage jar

ü                  Moisture (6 – 8 %)

SEED PACKING

ü                  Manila envelopes

ü                  Cloth bags

ü                  Plastic containers

BEST CONTAINERS

                Airtight sealed glass jar, metal can, foil   envelopes

EQUIPMENT AND MACHINERY

ü  Cleaner / Grader

ü                  Specific Gravity Separator

ü                  Indented Cylinder

CAUSES OF POOR VIABILITY OF TOMATO SEED

ü  Fruit picking at high temperature

ü                  Insufficient fermentation

ü                  Inadequate drying

ü                  High moisture level at storage

ü                  High temperature during storage

ü                  Fermentation in metallic containers

PROBLEMS WITH SEED STORAGE

ü  Mould and mildew

ü                  Temperature and moisture fluctuations

ü                  Insect weevils