Plant Breeding: Hybrid Seed, GMO Crops and Biotechnology MCQs 2026

Isolation distance in seed production is maintained mainly to prevent:

1. A uptake of phosphorus by roots ✓
2. B loss of soil moisture through evaporation ✓
3. C unwanted pollen contamination from other varieties ✓
4. D increase in seed size after harvest ✓

In hybrid seed production, heterosis primarily refers to which phenomenon?

1. A Superior performance of the F1 over its parents ✓
2. B Loss of vigour after repeated crossing ✓
3. C Sterility caused by cytoplasmic genes ✓
4. D Uniform ripening of parental lines ✓

Cytoplasmic male sterility is used in hybrid seed production mainly to:

1. A increase pollen production in the female parent ✓
2. B avoid manual emasculation by providing male-sterile female plants ✓
3. C convert a cross-pollinated crop into an apomictic crop ✓
4. D remove the need for genetic purity testing ✓

Self-incompatibility in Brassica hybrid seed production is useful because it:

1. A eliminates all insect pollinators from the seed field ✓
2. B converts diploid plants into tetraploids ✓
3. C prevents self-fertilization and promotes cross-pollination ✓
4. D guarantees resistance against all diseases ✓

In a CMS-based three-line hybrid system, the maintainer line generally has:

1. A restorer genes that make every F1 plant sterile ✓
2. B only recessive disease-resistance genes ✓
3. C no role in parental seed multiplication ✓
4. D the same nuclear genotype as the A line but fertile cytoplasm ✓

The main function of a restorer line in hybrid seed production is to:

1. A restore pollen fertility in the F1 hybrid ✓
2. B maintain cytoplasmic sterility in the A line ✓
3. C reduce germination percentage of hybrid seed ✓
4. D replace field isolation requirements ✓

Foundation seed of hybrid parent lines should be produced under:

1. A mixed cropping with unrelated varieties ✓
2. B strict isolation and genetic purity standards ✓
3. C delayed harvesting after shattering starts ✓
4. D open pollination without inspection ✓

A single-cross hybrid is best described as:

1. A a population maintained only by mass selection ✓
2. B a clone multiplied through cuttings ✓
3. C the F1 progeny from crossing two inbred lines ✓
4. D the F2 generation after farmer-saved hybrid seed ✓

Recurrent selection in plant breeding is designed mainly to:

1. A produce virus-free plants through meristem culture ✓
2. B test seed moisture before storage ✓
3. C measure chlorophyll content in mature leaves ✓
4. D increase the frequency of favourable genes in a population ✓

Combining ability of a line means its:

1. A capacity to transmit superior performance in crosses ✓
2. B ability to survive only under tissue culture ✓
3. C percentage of inert matter in seed samples ✓
4. D capacity to flower without vernalization ✓

General combining ability is mostly associated with:

1. A cytoplasmic inheritance only ✓
2. B additive gene effects ✓
3. C seed dormancy caused by hard seed coat ✓
4. D mechanical seed mixing during harvest ✓

Specific combining ability is most closely related to:

1. A soil salinity in the nursery ✓
2. B loss of seed viability during storage ✓
3. C non-additive gene effects ✓
4. D embryo rescue in wide crosses ✓

DUS testing for a new crop variety refers to evaluation for:

1. A Dormancy, Usefulness and Seed size ✓
2. B Disease index, Uniform rainfall and Soil type ✓
3. C Drying, Uptake and Storage capacity ✓
4. D Distinctness, Uniformity and Stability ✓

Bt crops express an insecticidal protein originally derived from:

1. A Bacillus thuringiensis ✓
2. B Rhizobium leguminosarum ✓
3. C Azotobacter chroococcum ✓
4. D Pseudomonas fluorescens ✓

Golden Rice was developed to increase the level of which nutrient precursor in the grain?

1. A nicotine ✓
2. B beta-carotene ✓
3. C caffeine ✓
4. D gossypol ✓

Agrobacterium-mediated transformation transfers foreign DNA through the:

1. A ribosomal RNA operon ✓
2. B chlorophyll molecule ✓
3. C T-DNA region of the Ti plasmid ✓
4. D seed storage protein body ✓

CRISPR-Cas9 genome editing usually begins by producing:

1. A random chromosome doubling in all cells ✓
2. B complete removal of cytoplasm from the ovule ✓
3. C conversion of RNA directly into starch ✓
4. D a targeted double-strand break at a guide-RNA-specified site ✓

A selectable marker gene in plant transformation is used to:

1. A identify transformed cells under selection pressure ✓
2. B measure seed vigour in the field ✓
3. C increase evaporation from culture media ✓
4. D replace the need for a promoter ✓

Marker-assisted selection uses DNA markers that are:

1. A visible only at flowering stage ✓
2. B linked to genes or QTLs controlling target traits ✓
3. C always produced by bacterial infection ✓
4. D unrelated to the plant genome ✓

Backcross breeding is most commonly used to transfer:

1. A all wild traits into a commercial variety without selection ✓
2. B only cytoplasmic organelles into pollen grains ✓
3. C one or a few specific genes into an elite recurrent parent ✓
4. D seed moisture from one lot to another ✓

Doubled haploid technology is valuable in plant breeding because it can:

1. A increase seed moisture content before storage ✓
2. B prevent every type of insect attack ✓
3. C make all hybrids perennial ✓
4. D rapidly produce completely homozygous lines ✓

Anther culture is mainly used to produce:

1. A haploid plants from microspores ✓
2. B synthetic pesticides from pollen ✓
3. C triploid endosperm without embryos ✓
4. D grafted seedlings for orchards ✓

Somaclonal variation refers to variation that arises during:

1. A ordinary seed certification sampling ✓
2. B tissue culture and plant regeneration ✓
3. C mechanical threshing of hybrid seed ✓
4. D controlled irrigation scheduling ✓

In plant tissue culture, callus is:

1. A a mature seed with low moisture ✓
2. B a pollen tube inside the style ✓
3. C an unorganized mass of undifferentiated cells ✓
4. D a certified hybrid seed tag ✓

Cryopreservation of plant genetic resources generally uses:

1. A hot water treatment above boiling point ✓
2. B field drying under direct sun ✓
3. C high oxygen storage at room temperature ✓
4. D liquid nitrogen at extremely low temperature ✓

A synthetic seed is commonly described as:

1. A an encapsulated somatic embryo or propagule ✓
2. B a seed produced only by wind pollination ✓
3. C a seed lot without any certification label ✓
4. D a grain coated only with fertilizer dust ✓

Genetic use restriction technology is often discussed because it may:

1. A increase natural apomixis in all crops ✓
2. B prevent farmers from obtaining viable second-generation seed ✓
3. C make all pollen grains fertile in CMS lines ✓
4. D replace the need for variety registration ✓

A non-Bt refuge is recommended with Bt cotton mainly to:

1. A increase seed dormancy of the hybrid ✓
2. B eliminate the need for pest monitoring ✓
3. C delay the evolution of resistance in target insects ✓
4. D convert cotton into a self-incompatible crop ✓

RNA interference technology regulates genes through:

1. A direct conversion of DNA bases into proteins ✓
2. B chromosome doubling by colchicine fumes ✓
3. C random removal of all introns before transcription ✓
4. D sequence-specific gene silencing triggered by double-stranded RNA ✓

Gene flow from a transgenic crop to nearby compatible plants can be reduced by:

1. A isolation distance and appropriate biological containment measures ✓
2. B mixing harvested seed from several fields ✓
3. C planting susceptible varieties as border rows only ✓
4. D removing labels from seed bags ✓

Hybrid seed production in many self-pollinated crops becomes practical when breeders use:

1. A high seed moisture to promote storage fungi ✓
2. B male sterility systems to reduce the need for emasculation ✓
3. C continuous selfing of the commercial F1 crop ✓
4. D manual mixing of F2 seed after harvest ✓

The pedigree method is most suited for breeding self-pollinated crops when the breeder wants to:

1. A multiply clonal rootstocks without sexual reproduction ✓
2. B avoid keeping any ancestry information ✓
3. C select individual plants in segregating generations with records ✓
4. D produce only cytoplasmic mutants ✓

The bulk method in self-pollinated crop breeding relies initially on:

1. A hand pollinating each flower with stored pollen ✓
2. B using only tissue culture media for every generation ✓
3. C maintaining male sterility through restorer lines ✓
4. D advancing a mixed segregating population with limited early selection ✓

Mutation breeding commonly uses:

1. A physical or chemical mutagens to create new variation ✓
2. B only normal irrigation water as a mutagen ✓
3. C seed certification tags to alter genes ✓
4. D emasculation without pollination ✓

Pure-line selection is most applicable to:

1. A vegetatively propagated banana only ✓
2. B self-pollinated crops with naturally homozygous variation ✓
3. C hybrid seed lots after F2 segregation ✓
4. D male-sterile cytoplasm maintenance only ✓

A synthetic variety differs from a single-cross hybrid because it is generally:

1. A always produced from two inbred lines only ✓
2. B sterile in the first generation ✓
3. C maintained by open pollination among selected parents ✓
4. D made only through CRISPR editing ✓

Colchicine is used in plant breeding mainly to induce:

1. A cytoplasmic male sterility in every species ✓
2. B rapid seed drying in storage ✓
3. C bacterial transformation of leaf discs ✓
4. D polyploidy by interfering with spindle formation ✓

QTL mapping is used to identify:

1. A genomic regions associated with quantitative traits ✓
2. B the exact seed moisture of every grain ✓
3. C only visible off-types in a seed field ✓
4. D the age of stored pesticide containers ✓

An SNP marker represents:

1. A a synthetic nutrient package for tissue culture ✓
2. B a single nucleotide polymorphism at a DNA site ✓
3. C a seed nursery protocol for hybrid maize ✓
4. D a soil nitrogen pressure measurement ✓

Biosafety assessment of a genetically modified crop commonly includes:

1. A only the colour of the seed coat ✓
2. B only the market price of the variety ✓
3. C food and feed safety plus environmental risk evaluation ✓
4. D the farmer name on the seed bag ✓

In GMO regulation, an event usually means:

1. A a harvest festival for certified seed ✓
2. B a flowering stage of all parental lines ✓
3. C a standard irrigation interval after sowing ✓
4. D a unique insertion of a transgene in the plant genome ✓

A typical plant tissue culture medium contains:

1. A mineral salts, carbon source, vitamins and plant growth regulators ✓
2. B only field soil and untreated canal water ✓
3. C dry seed samples and threshing dust ✓
4. D only pollen grains suspended in oil ✓

In tissue culture, a relatively high auxin-to-cytokinin ratio generally favours:

1. A pollen sterility in field plants ✓
2. B root formation ✓
3. C seed certification tagging ✓
4. D fruit ripening after harvest ✓

Totipotency in plant cells means the ability to:

1. A produce only sterile pollen grains ✓
2. B absorb nitrogen without roots ✓
3. C regenerate a complete plant from a single cell ✓
4. D ripen fruit without ethylene ✓

Apomixis could be valuable in hybrid crops because it may allow:

1. A complete loss of embryo development ✓
2. B manual emasculation in every flower ✓
3. C conversion of all annual crops into weeds ✓
4. D clonal seed formation that fixes hybrid vigour ✓

The primary purpose of seed certification is to ensure:

1. A genetic purity and prescribed seed quality standards ✓
2. B maximum weed growth in seed fields ✓
3. C uncontrolled crossing among varieties ✓
4. D minimum germination of hybrid seed ✓

Rogueing in a seed production field means:

1. A mixing several varieties before flowering ✓
2. B removing off-type or diseased plants ✓
3. C delaying all inspections until storage ✓
4. D adding inert matter to seed samples ✓

Farm-saved seed from a commercial F1 hybrid often gives non-uniform progeny because:

1. A the seed cannot absorb water ✓
2. B all F1 plants are apomictic ✓
3. C hybrid vigour increases indefinitely every year ✓
4. D the F2 generation segregates genetically ✓

A key advantage of marker-assisted selection is that it can permit:

1. A selection at the seedling stage without waiting for full phenotype ✓
2. B seed multiplication without genetic testing ✓
3. C complete removal of field trials in all cases ✓
4. D replacement of all parental lines by fertilizers ✓

Regulatory approval of a GMO crop is generally based on:

1. A only the height of the plant at maturity ✓
2. B case-by-case risk assessment of the specific event and use ✓
3. C automatic approval of all crops with the same promoter ✓
4. D seed colour comparison with local varieties ✓