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

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

1. ASuperior performance of the F1 over its parents✓
2. BLoss of vigour after repeated crossing✓
3. CSterility caused by cytoplasmic genes✓
4. DUniform ripening of parental lines✓

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

1. Aincrease pollen production in the female parent✓
2. Bavoid manual emasculation by providing male-sterile female plants✓
3. Cconvert a cross-pollinated crop into an apomictic crop✓
4. Dremove the need for genetic purity testing✓

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

1. Aeliminates all insect pollinators from the seed field✓
2. Bconverts diploid plants into tetraploids✓
3. Cprevents self-fertilization and promotes cross-pollination✓
4. Dguarantees resistance against all diseases✓

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

1. Arestorer genes that make every F1 plant sterile✓
2. Bonly recessive disease-resistance genes✓
3. Cno role in parental seed multiplication✓
4. Dthe same nuclear genotype as the A line but fertile cytoplasm✓

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

1. Arestore pollen fertility in the F1 hybrid✓
2. Bmaintain cytoplasmic sterility in the A line✓
3. Creduce germination percentage of hybrid seed✓
4. Dreplace field isolation requirements✓

Foundation seed of hybrid parent lines should be produced under:

1. Amixed cropping with unrelated varieties✓
2. Bstrict isolation and genetic purity standards✓
3. Cdelayed harvesting after shattering starts✓
4. Dopen pollination without inspection✓

A single-cross hybrid is best described as:

1. Aa population maintained only by mass selection✓
2. Ba clone multiplied through cuttings✓
3. Cthe F1 progeny from crossing two inbred lines✓
4. Dthe F2 generation after farmer-saved hybrid seed✓

Recurrent selection in plant breeding is designed mainly to:

1. Aproduce virus-free plants through meristem culture✓
2. Btest seed moisture before storage✓
3. Cmeasure chlorophyll content in mature leaves✓
4. Dincrease the frequency of favourable genes in a population✓

Combining ability of a line means its:

1. Acapacity to transmit superior performance in crosses✓
2. Bability to survive only under tissue culture✓
3. Cpercentage of inert matter in seed samples✓
4. Dcapacity to flower without vernalization✓

General combining ability is mostly associated with:

1. Acytoplasmic inheritance only✓
2. Badditive gene effects✓
3. Cseed dormancy caused by hard seed coat✓
4. Dmechanical seed mixing during harvest✓

Specific combining ability is most closely related to:

1. Asoil salinity in the nursery✓
2. Bloss of seed viability during storage✓
3. Cnon-additive gene effects✓
4. Dembryo rescue in wide crosses✓

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

1. ADormancy, Usefulness and Seed size✓
2. BDisease index, Uniform rainfall and Soil type✓
3. CDrying, Uptake and Storage capacity✓
4. DDistinctness, Uniformity and Stability✓

Bt crops express an insecticidal protein originally derived from:

1. ABacillus thuringiensis✓
2. BRhizobium leguminosarum✓
3. CAzotobacter chroococcum✓
4. DPseudomonas fluorescens✓

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

1. Anicotine✓
2. Bbeta-carotene✓
3. Ccaffeine✓
4. Dgossypol✓

Agrobacterium-mediated transformation transfers foreign DNA through the:

1. Aribosomal RNA operon✓
2. Bchlorophyll molecule✓
3. CT-DNA region of the Ti plasmid✓
4. Dseed storage protein body✓

CRISPR-Cas9 genome editing usually begins by producing:

1. Arandom chromosome doubling in all cells✓
2. Bcomplete removal of cytoplasm from the ovule✓
3. Cconversion of RNA directly into starch✓
4. Da targeted double-strand break at a guide-RNA-specified site✓

A selectable marker gene in plant transformation is used to:

1. Aidentify transformed cells under selection pressure✓
2. Bmeasure seed vigour in the field✓
3. Cincrease evaporation from culture media✓
4. Dreplace the need for a promoter✓

Marker-assisted selection uses DNA markers that are:

1. Avisible only at flowering stage✓
2. Blinked to genes or QTLs controlling target traits✓
3. Calways produced by bacterial infection✓
4. Dunrelated to the plant genome✓

Backcross breeding is most commonly used to transfer:

1. Aall wild traits into a commercial variety without selection✓
2. Bonly cytoplasmic organelles into pollen grains✓
3. Cone or a few specific genes into an elite recurrent parent✓
4. Dseed moisture from one lot to another✓

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

1. Aincrease seed moisture content before storage✓
2. Bprevent every type of insect attack✓
3. Cmake all hybrids perennial✓
4. Drapidly produce completely homozygous lines✓

Anther culture is mainly used to produce:

1. Ahaploid plants from microspores✓
2. Bsynthetic pesticides from pollen✓
3. Ctriploid endosperm without embryos✓
4. Dgrafted seedlings for orchards✓

Somaclonal variation refers to variation that arises during:

1. Aordinary seed certification sampling✓
2. Btissue culture and plant regeneration✓
3. Cmechanical threshing of hybrid seed✓
4. Dcontrolled irrigation scheduling✓

In plant tissue culture, callus is:

1. Aa mature seed with low moisture✓
2. Ba pollen tube inside the style✓
3. Can unorganized mass of undifferentiated cells✓
4. Da certified hybrid seed tag✓

Cryopreservation of plant genetic resources generally uses:

1. Ahot water treatment above boiling point✓
2. Bfield drying under direct sun✓
3. Chigh oxygen storage at room temperature✓
4. Dliquid nitrogen at extremely low temperature✓

A synthetic seed is commonly described as:

1. Aan encapsulated somatic embryo or propagule✓
2. Ba seed produced only by wind pollination✓
3. Ca seed lot without any certification label✓
4. Da grain coated only with fertilizer dust✓

Genetic use restriction technology is often discussed because it may:

1. Aincrease natural apomixis in all crops✓
2. Bprevent farmers from obtaining viable second-generation seed✓
3. Cmake all pollen grains fertile in CMS lines✓
4. Dreplace the need for variety registration✓

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

1. Aincrease seed dormancy of the hybrid✓
2. Beliminate the need for pest monitoring✓
3. Cdelay the evolution of resistance in target insects✓
4. Dconvert cotton into a self-incompatible crop✓

RNA interference technology regulates genes through:

1. Adirect conversion of DNA bases into proteins✓
2. Bchromosome doubling by colchicine fumes✓
3. Crandom removal of all introns before transcription✓
4. Dsequence-specific gene silencing triggered by double-stranded RNA✓

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

1. Aisolation distance and appropriate biological containment measures✓
2. Bmixing harvested seed from several fields✓
3. Cplanting susceptible varieties as border rows only✓
4. Dremoving labels from seed bags✓

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

1. Ahigh seed moisture to promote storage fungi✓
2. Bmale sterility systems to reduce the need for emasculation✓
3. Ccontinuous selfing of the commercial F1 crop✓
4. Dmanual mixing of F2 seed after harvest✓

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

1. Amultiply clonal rootstocks without sexual reproduction✓
2. Bavoid keeping any ancestry information✓
3. Cselect individual plants in segregating generations with records✓
4. Dproduce only cytoplasmic mutants✓

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

1. Ahand pollinating each flower with stored pollen✓
2. Busing only tissue culture media for every generation✓
3. Cmaintaining male sterility through restorer lines✓
4. Dadvancing a mixed segregating population with limited early selection✓

Mutation breeding commonly uses:

1. Aphysical or chemical mutagens to create new variation✓
2. Bonly normal irrigation water as a mutagen✓
3. Cseed certification tags to alter genes✓
4. Demasculation without pollination✓

Pure-line selection is most applicable to:

1. Avegetatively propagated banana only✓
2. Bself-pollinated crops with naturally homozygous variation✓
3. Chybrid seed lots after F2 segregation✓
4. Dmale-sterile cytoplasm maintenance only✓

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

1. Aalways produced from two inbred lines only✓
2. Bsterile in the first generation✓
3. Cmaintained by open pollination among selected parents✓
4. Dmade only through CRISPR editing✓

Colchicine is used in plant breeding mainly to induce:

1. Acytoplasmic male sterility in every species✓
2. Brapid seed drying in storage✓
3. Cbacterial transformation of leaf discs✓
4. Dpolyploidy by interfering with spindle formation✓

QTL mapping is used to identify:

1. Agenomic regions associated with quantitative traits✓
2. Bthe exact seed moisture of every grain✓
3. Conly visible off-types in a seed field✓
4. Dthe age of stored pesticide containers✓

An SNP marker represents:

1. Aa synthetic nutrient package for tissue culture✓
2. Ba single nucleotide polymorphism at a DNA site✓
3. Ca seed nursery protocol for hybrid maize✓
4. Da soil nitrogen pressure measurement✓

Biosafety assessment of a genetically modified crop commonly includes:

1. Aonly the colour of the seed coat✓
2. Bonly the market price of the variety✓
3. Cfood and feed safety plus environmental risk evaluation✓
4. Dthe farmer name on the seed bag✓

In GMO regulation, an event usually means:

1. Aa harvest festival for certified seed✓
2. Ba flowering stage of all parental lines✓
3. Ca standard irrigation interval after sowing✓
4. Da unique insertion of a transgene in the plant genome✓

A typical plant tissue culture medium contains:

1. Amineral salts, carbon source, vitamins and plant growth regulators✓
2. Bonly field soil and untreated canal water✓
3. Cdry seed samples and threshing dust✓
4. Donly pollen grains suspended in oil✓

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

1. Apollen sterility in field plants✓
2. Broot formation✓
3. Cseed certification tagging✓
4. Dfruit ripening after harvest✓

Totipotency in plant cells means the ability to:

1. Aproduce only sterile pollen grains✓
2. Babsorb nitrogen without roots✓
3. Cregenerate a complete plant from a single cell✓
4. Dripen fruit without ethylene✓

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

1. Acomplete loss of embryo development✓
2. Bmanual emasculation in every flower✓
3. Cconversion of all annual crops into weeds✓
4. Dclonal seed formation that fixes hybrid vigour✓

The primary purpose of seed certification is to ensure:

1. Agenetic purity and prescribed seed quality standards✓
2. Bmaximum weed growth in seed fields✓
3. Cuncontrolled crossing among varieties✓
4. Dminimum germination of hybrid seed✓

Rogueing in a seed production field means:

1. Amixing several varieties before flowering✓
2. Bremoving off-type or diseased plants✓
3. Cdelaying all inspections until storage✓
4. Dadding inert matter to seed samples✓

Isolation distance in seed production is maintained mainly to prevent:

1. Auptake of phosphorus by roots✓
2. Bloss of soil moisture through evaporation✓
3. Cunwanted pollen contamination from other varieties✓
4. Dincrease in seed size after harvest✓

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

1. Athe seed cannot absorb water✓
2. Ball F1 plants are apomictic✓
3. Chybrid vigour increases indefinitely every year✓
4. Dthe F2 generation segregates genetically✓

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

1. Aselection at the seedling stage without waiting for full phenotype✓
2. Bseed multiplication without genetic testing✓
3. Ccomplete removal of field trials in all cases✓
4. Dreplacement of all parental lines by fertilizers✓

Regulatory approval of a GMO crop is generally based on:

1. Aonly the height of the plant at maturity✓
2. Bcase-by-case risk assessment of the specific event and use✓
3. Cautomatic approval of all crops with the same promoter✓
4. Dseed colour comparison with local varieties✓