ICAR AICE-JRF/SRF (PhD) — Subject 59 Forestry · India · National Testing Agency for ICAR
Original practice questions written to the published syllabus · not past papersThe genetics of forest trees and how breeding programmes select, test and deploy better trees: provenance trials, plus trees, seed orchards, progeny tests, clonal forestry and genetic gain.
In the exams: IFoS Forestry Paper I Section B (tree improvement and seed technology); ICAR AICE-JRF 59 Unit 3; ICAR AIEEA-PG Group 09 (forest genetics and tree improvement)
ICAR AICE-JRF/SRF (PhD) — Subject 59 Forestry, Unit 3
Hardy-Weinberg calculations, drift and effective population size, mating systems, heritability and the breeder's equation, mating and field designs, GCA and SCA, hybridisation, polyploidy and molecular markers.
How our questions for ICAR AICE-JRF/SRF spread across the units of Forest Genetics & Tree Improvement. Difficulty: 3 easy, 9 medium, 9 hard.
| Basics of forest genetics: inheritance, Hardy-Weinberg, drift, gene flow | 2 | |
| Mating systems and pollination biology of forest trees | 2 | |
| Seed orchards: clonal and seedling, layout and management | 2 | |
| Progeny tests and field designs | 2 | |
| Heritability, selection differential and genetic gain | 2 | |
| Exotics, land races and species introduction | 2 | |
| Clonal forestry: merits, risks and deployment | 2 | |
| Hybridisation and polyploidy in trees | 2 | |
| Molecular markers and genomic selection in trees | 2 | |
| Variation in natural populations and its causes | 1 | |
| Provenance and seed source; provenance testing | 1 | |
| Selection of plus trees and seed production areas | 1 |
Choose an answer, then open the working. Each explanation says why the right answer is right and why the others are not.
In a population, 4 per cent of seedlings show a recessive trait. Assuming Hardy-Weinberg equilibrium, what is the frequency of heterozygous carriers?
A. 0.32
q² = 0.04 → q = 0.2, p = 0.8; 2pq = 0.32. 0.64 is p²; 0.16 is pq, forgetting the factor 2; 0.04 is q².
Further reading: White, Adams & Neale, Forest Genetics (2007); Zobel & Talbert, Applied Forest Tree Improvement (1984); Falconer & Mackay, Introduction to Quantitative Genetics (4th ed., 1996)
Selfed offspring of conifers typically show:
C. Inbreeding depression
Selfing exposes deleterious recessives.
Further reading: White, Adams & Neale, Forest Genetics (2007); Zobel & Talbert, Applied Forest Tree Improvement (1984); Falconer & Mackay, Introduction to Quantitative Genetics (4th ed., 1996)
Which treatment is widely used to induce flowering in many conifer breeding programmes?
B. Gibberellins A4/7
GA4/7 promotes flowering in many conifers; colchicine doubles chromosomes; TZ tests viability; acid scarifies seed.
Further reading: White, Adams & Neale, Forest Genetics (2007); Zobel & Talbert, Applied Forest Tree Improvement (1984); Falconer & Mackay, Introduction to Quantitative Genetics (4th ed., 1996)
When provenances rank differently at different sites, there is:
B. G × E interaction
G × E means recommendations must be made by planting zone.
Further reading: White, Adams & Neale, Forest Genetics (2007); Zobel & Talbert, Applied Forest Tree Improvement (1984); Falconer & Mackay, Introduction to Quantitative Genetics (4th ed., 1996)
Full-sib progeny tests allow estimation of:
B. Both GCA and SCA
Known parent pairs let specific combining ability be separated.
Further reading: White, Adams & Neale, Forest Genetics (2007); Zobel & Talbert, Applied Forest Tree Improvement (1984); Falconer & Mackay, Introduction to Quantitative Genetics (4th ed., 1996)
A land race is:
A. A locally adapted exotic population
Land races develop through natural selection after introduction.
Further reading: White, Adams & Neale, Forest Genetics (2007); Zobel & Talbert, Applied Forest Tree Improvement (1984); Falconer & Mackay, Introduction to Quantitative Genetics (4th ed., 1996)
Dunkeld larch is the hybrid of:
C. European × Japanese larch
Larix × marschlinsii combines European and Japanese larch.
Further reading: White, Adams & Neale, Forest Genetics (2007); Zobel & Talbert, Applied Forest Tree Improvement (1984); Falconer & Mackay, Introduction to Quantitative Genetics (4th ed., 1996)
Which conifer is a well-known natural polyploid (hexaploid)?
A. Coast redwood
Sequoia sempervirens is hexaploid; polyploidy is rare in conifers.
Further reading: White, Adams & Neale, Forest Genetics (2007); Zobel & Talbert, Applied Forest Tree Improvement (1984); Falconer & Mackay, Introduction to Quantitative Genetics (4th ed., 1996)
Single nucleotide polymorphisms (SNPs) are useful mainly because they are:
D. Abundant genome-wide and easy to genotype
SNP arrays and sequencing genotype thousands of loci.
Further reading: White, Adams & Neale, Forest Genetics (2007); Zobel & Talbert, Applied Forest Tree Improvement (1984); Falconer & Mackay, Introduction to Quantitative Genetics (4th ed., 1996)
Why has marker-assisted selection on a few QTL had limited impact in forest trees?
B. QTL explain little variation and are family-specific
Small, inconsistent QTL effects limit MAS; GS uses the whole genome instead.
Further reading: White, Adams & Neale, Forest Genetics (2007); Zobel & Talbert, Applied Forest Tree Improvement (1984); Falconer & Mackay, Introduction to Quantitative Genetics (4th ed., 1996)
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