ICAR AICE-JRF/SRF Forest Tree Seed Technology: practice questions

ICAR AICE-JRF/SRF (PhD) — Subject 59 Forestry · India · National Testing Agency for ICAR

Original practice questions written to the published syllabus · not past papers

10worked here, free

19written to this exam in this subject

10syllabus units

What this subject covers

Collecting, processing, storing, testing and certifying tree seed so that nurseries get the right seed of known quality and origin.

In the exams: ICAR AICE-JRF 59 Unit 2 (seed collection, dormancy, testing, ISTA rules, certification); IFoS Forestry Paper I Section B; ICAR AIEEA-PG Group 09 (tree seed technology)

Seed development, maturity indices and seed years
Seed collection methods and timing
Seed extraction, cleaning and processing
Orthodox, intermediate and recalcitrant seed and their storage
Seed dormancy types and pre-treatments
Seed testing: purity, moisture, viability (tetrazolium), germination
ISTA rules and seed testing standards
Seed certification and the OECD Forest Seed and Plant Scheme
Seed zones, seed sources and documentation of origin
Seed pests and seed health

What ICAR AICE-JRF/SRF asks from it

ICAR AICE-JRF/SRF (PhD) — Subject 59 Forestry, Unit 2

Seed maturity indices, collection, processing, orthodox and recalcitrant storage, dormancy classes and pre-treatments, seed testing (purity, moisture, tetrazolium, germination), ISTA rules and certificates, and OECD certification categories.

Where the 19 questions fall

How our questions for ICAR AICE-JRF/SRF spread across the units of Forest Tree Seed Technology. Difficulty: 0 easy, 9 medium, 10 hard.

Seed testing: purity, moisture, viability (tetrazolium), germination	3
Seed development, maturity indices and seed years	2
Seed collection methods and timing	2
Seed extraction, cleaning and processing	2
Orthodox, intermediate and recalcitrant seed and their storage	2
Seed dormancy types and pre-treatments	2
ISTA rules and seed testing standards	2
Seed certification and the OECD Forest Seed and Plant Scheme	2
Seed zones, seed sources and documentation of origin	1
Seed pests and seed health	1

10 practice questions, worked

Choose an answer, then open the working. Each explanation says why the right answer is right and why the others are not.

1 · Seed development, maturity indices and seed years · medium

Which statement correctly contrasts orthodox and recalcitrant seed development?

Recalcitrant seeds undergo maturation drying; orthodox seeds are shed moist
Both are shed moist and dry only after falling to the ground
Both undergo maturation drying to about two per cent moisture
Orthodox seeds undergo maturation drying; recalcitrant seeds are shed moist

Answer and working

D. Orthodox seeds undergo maturation drying; recalcitrant seeds are shed moist

Orthodox seeds dry and gain desiccation tolerance at the end of development; recalcitrant seeds skip this phase and are shed with high moisture.

Further reading: Schmidt, Guide to Handling of Tropical and Subtropical Forest Seed (2000); Bonner & Karrfalt, The Woody Plant Seed Manual (2008); ISTA International Rules for Seed Testing

2 · Seed collection methods and timing · medium

Why are sheets or nets spread under trees for ground collection of large fruits?

To prevent fruits from falling until they are fully dry
To catch fruits cleanly and keep them off the soil
To shade the fruits so that they ripen more slowly
To trap seed insects before they reach the fruits

Answer and working

B. To catch fruits cleanly and keep them off the soil

Nets keep fruits clean and reduce soil-borne contamination and losses. They do not stop fruit fall, shade fruits or trap insects.

Further reading: Schmidt, Guide to Handling of Tropical and Subtropical Forest Seed (2000); Bonner & Karrfalt, The Woody Plant Seed Manual (2008); ISTA International Rules for Seed Testing

3 · Seed extraction, cleaning and processing · hard

The incubation-drying-separation (IDS) method upgrades conifer seed lots because:

After incubation, dead seeds germinate faster and can be picked out
After drying, all seeds become equally heavy and are easy to count
After brief drying, live seeds hold more water than dead ones and sink
After incubation, insects leave the seeds and are blown away

Answer and working

C. After brief drying, live seeds hold more water than dead ones and sink

Live seeds lose water more slowly during the drying step, so they stay heavier and sink in flotation while dead seeds float.

Further reading: Schmidt, Guide to Handling of Tropical and Subtropical Forest Seed (2000); Bonner & Karrfalt, The Woody Plant Seed Manual (2008); ISTA International Rules for Seed Testing

4 · Orthodox, intermediate and recalcitrant seed and their storage · medium

According to Harrington's rules of thumb, reducing seed moisture content from 10 to 7 per cent would extend storage life roughly:

Threefold
Sixfold
Thirtyfold
Eightfold

Answer and working

D. Eightfold

Each 1% reduction roughly doubles life: three reductions give 2 × 2 × 2 = 8. Threefold adds instead of doubling; sixfold multiplies 2 × 3.

Further reading: Schmidt, Guide to Handling of Tropical and Subtropical Forest Seed (2000); Bonner & Karrfalt, The Woody Plant Seed Manual (2008); ISTA International Rules for Seed Testing

5 · Orthodox, intermediate and recalcitrant seed and their storage · hard

Which method can conserve recalcitrant germplasm for long periods in research gene banks?

Drying whole seeds to two per cent moisture and storing at 20 °C
Storing whole seeds in sealed tins at room temperature for decades
Soaking whole seeds in acid and storing them in the dark
Cryopreservation of embryos or embryonic axes in liquid nitrogen

Answer and working

D. Cryopreservation of embryos or embryonic axes in liquid nitrogen

Excised embryos or axes can be cryopreserved; whole recalcitrant seeds cannot be dried or stored long by conventional methods.

Further reading: Schmidt, Guide to Handling of Tropical and Subtropical Forest Seed (2000); Bonner & Karrfalt, The Woody Plant Seed Manual (2008); ISTA International Rules for Seed Testing

6 · Seed dormancy types and pre-treatments · medium

Morphological dormancy means that at dispersal:

The seed coat is impermeable and must be cracked
The embryo is too small and must grow first
The seed is dead and cannot germinate
The seed has already germinated inside the fruit

Answer and working

B. The embryo is too small and must grow first

In morphological dormancy the embryo is small and grows inside the seed before germination.

Further reading: Schmidt, Guide to Handling of Tropical and Subtropical Forest Seed (2000); Bonner & Karrfalt, The Woody Plant Seed Manual (2008); ISTA International Rules for Seed Testing

7 · Seed testing: purity, moisture, viability (tetrazolium), germination · medium

The same sample (10.0 g fresh, 9.1 g dry) expressed on a dry-weight basis has a moisture content of:

9.0 per cent
1.1 per cent
8.2 per cent
9.9 per cent

Answer and working

D. 9.9 per cent

Dry basis = water ÷ dry weight × 100 = 0.9 ÷ 9.1 × 100 = 9.9%. 9.0% is the fresh basis; the others are arithmetic slips.

Further reading: Schmidt, Guide to Handling of Tropical and Subtropical Forest Seed (2000); Bonner & Karrfalt, The Woody Plant Seed Manual (2008); ISTA International Rules for Seed Testing

8 · Seed testing: purity, moisture, viability (tetrazolium), germination · hard

A germination test runs 20 days with 80 per cent final germination; the highest cumulative germination per day is 48 per cent by day 8. What is Czabator's germination value?

Answer and working

A. 24

Mean daily germination = 80 ÷ 20 = 4; peak value = 48 ÷ 8 = 6; GV = 6 × 4 = 24. 10 adds them; 6 is peak value only; 128 multiplies 80 × 1.6.

Further reading: Schmidt, Guide to Handling of Tropical and Subtropical Forest Seed (2000); Bonner & Karrfalt, The Woody Plant Seed Manual (2008); ISTA International Rules for Seed Testing

9 · Seed certification and the OECD Forest Seed and Plant Scheme · hard

Seed testing and seed certification differ because:

Testing assures genetic origin; certification measures germination
Testing applies only to imports; certification only to exports
Testing is voluntary everywhere; certification is illegal in some countries
Testing gauges seed quality; certification assures origin and genetics

Answer and working

D. Testing gauges seed quality; certification assures origin and genetics

A lot can have high germination but unknown or poor origin; certification addresses origin and genetic quality.

Further reading: Schmidt, Guide to Handling of Tropical and Subtropical Forest Seed (2000); Bonner & Karrfalt, The Woody Plant Seed Manual (2008); ISTA International Rules for Seed Testing

10 · Seed pests and seed health · medium

A blotter test in seed health testing involves:

Weighing seeds before and after drying in an oven
Incubating seeds on moist paper to grow fungi
Staining seeds with tetrazolium to see live tissues
Floating seeds in water to remove empty ones

Answer and working

B. Incubating seeds on moist paper to grow fungi

Blotter and agar tests reveal seed-borne fungi. The other procedures are moisture, viability and cleaning tests.

Further reading: Schmidt, Guide to Handling of Tropical and Subtropical Forest Seed (2000); Bonner & Karrfalt, The Woody Plant Seed Manual (2008); ISTA International Rules for Seed Testing

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