AGA112: Chapter 3 (Short Answer)

Define seed germination (1 mark)

Answer explanation

activation of seed’s metabolic (0.5 mark)

and emerge to become a new seedling (0.5 mark)

State three (3) conditions that must be fulfilled to initiate seed germination (3 marks)

Answer explanation

i. seed must be alive and able to germinate (1 m)

ii. seed must be subjected to appropriate environmental condition (1 m)

iii. any primary dormancy present within seed must be overcome (1 m)

Define seed dormancy (1 mark)

Answer explanation

seed will not germinate (0.5 m)

even when environment is suitable for germination (0.5 m)

Identify three (3) types of seed dormancy. (3 marks)

Answer explanation

i. seed coat dormancy (1 m)

ii. embryonic dormancy (1 m)

iii. immature embryo/ rudimentary embryyo (1 m)

Give any two (2) types of seed storage. (2 marks)

Answer explanation

i. open storage (1 m)

ii. storage in sealed container (1 m)

iii. storage with humidity and temperature control

Explain two (2) tests that determine seed viability.  (5 marks)

Answer explanation

i. Germination Test (0.5 m)

- take small portion of seed (1 m)

- moist the seed (1 m)

- place between 2 wet gunny sack

- wait 7-10 days

- check total number of germinated seeds

-use formula: no. of seed germinates/total no. of seeds x 100%

ii. Tetrazolium Test (0.5 m)

- seed soak in TTC solution (1 m)

- biochemical test for viability (1 m)

- living tissue change to insoluble red compound

- non-living tissue remain white

Present the process to transplant the seedlings to the field planting area. (3 marks)

Answer explanation

- seedling tend to have transplant shock when transplanting (1 m)

- plant need to be hardening off (1 m)

- this will reduce transplant shock (1 m)

- supply more water immediately after transplanting

Describe three (3) methods to overcome seed dormancy. (3 marks)

Answer explanation

i. Scarification by physical damaging seed surface (1 m)

ii. Soaking seed in cold water for a period of time (1 m)

iii. Soaking seed in hot water for a period of time (1 m)

iv. Acid scarification by soaking seed in dilute acid solution

Discuss two (2) types of seed treatments. (5 marks)

Answer explanation

i. Seed protectant (0.5 m)

- fungicide is used to protect seed from pathogen from soil (1 m)

- beneficial when germination is delayed due to excessive water in soil (1 m)

ii. Germination enhancement (0.5 m)

- seed sizing eliminates light and cracked seeds (1 m)

- so, higher potential of viability and vigor (1 m)

iii. Coatings for sowing (0.5 m)

- example is polymer film-coated seed (1 m)

- use thin polymer to cover seed (1 m)