1: Stock-Scion Relationship
- Which of the following factors is most influenced by the rootstock in a grafted plant?
a) Fruit size
b) Tree vigor
c) Flower color
d) Fruit aroma - The scion primarily influences which characteristic in the grafted plant?
a) Fruit quality
b) Drought tolerance
c) Root architecture
d) Nutrient uptake - Which of the following is a direct effect of rootstock on scion in mango cultivation?
a) Enhancing sweetness of fruit
b) Inducing dwarfness
c) Increasing oil content
d) Boosting anthocyanin - Which factor is least influenced by the stock in a scion-rootstock combination?
a) Tree size
b) Disease resistance
c) Genetic fruit flavor
d) Stress tolerance - In apple, M9 rootstock is preferred for:
a) Larger fruit size
b) Dwarfing effect on scion
c) Better flowering
d) Disease resistance in scion - Which physiological trait can be significantly altered in the scion by selecting a suitable rootstock?
a) Flower color
b) Water use efficiency
c) Fruit shape
d) Leaf venation pattern - A vigorous rootstock under a weak scion can lead to:
a) Early fruiting
b) Graft failure due to incompatibility
c) High fruit quality
d) Low nutrient uptake - The rootstock can influence flowering in the scion by modifying:
a) Soil pH
b) Leaf pigmentation
c) Hormonal balance
d) Pollen viability - Which crop is most known for stock-scion interactions related to salinity tolerance?
a) Apple
b) Guava
c) Citrus
d) Pear - Which mechanism allows the stock to regulate scion transpiration rate?
a) Phloem loading
b) Fruit load control
c) Stomatal conductance regulation
d) Photosynthetic feedback - In grapevine, which aspect is commonly influenced by the rootstock?
a) Berry color
b) Nutrient uptake efficiency
c) Inflorescence type
d) Anthocyanin synthesis - What is the effect of a dwarfing rootstock on the scion?
a) Induces chlorosis
b) Reduces internodal length
c) Enhances seed viability
d) Increases pollination - Rootstock affects the scion’s resistance to abiotic stress mainly through:
a) Chloroplast mutation
b) Improved water and nutrient absorption
c) Genetic change in scion
d) Altered stomatal DNA - Which stock-scion combination in citrus is known for its high yield and compatibility?
a) Nagpur mandarin on Carrizo citrange
b) Nagpur mandarin on Cleopatra
c) Kinnow on Rough lemon
d) Acid lime on Rangpur lime - Rootstock can reduce susceptibility to soil-borne diseases in scion by:
a) Changing leaf pH
b) Acting as a barrier to pathogen entry
c) Enhancing leaf cuticle
d) Stimulating flower bud dormancy - In mango, dwarfing effect is achieved using which stock?
a) Alphonso
b) Vellaikolamban
c) Langra
d) Banganapalli - Which scion trait is least likely to be influenced by the rootstock?
a) Flowering time
b) Fruit DNA sequence
c) Tree height
d) Nutrient use efficiency - One of the biochemical effects of rootstock on scion includes changes in:
a) Xylem fiber width
b) Bud phyllotaxy
c) Hormone transport
d) Ovule number - In apple, MM106 rootstock imparts what characteristic to the scion?
a) Ultra dwarfing
b) Semi-dwarfing
c) High salinity tolerance
d) Scab immunity - The long-distance signaling from rootstock to scion is mediated by:
a) Mineral ions
b) Hormones and RNAs
c) Cellulose
d) Xylem-only flow - Which fruit crop exhibits a significant impact of stock on scion sugar accumulation?
a) Litchi
b) Banana
c) Grapes
d) Papaya - The rootstock-scion relationship becomes more predictable when:
a) Both are genetically similar
b) Scion is from a different genus
c) Interstock is genetically diverse
d) Environmental conditions are extreme - In rootstock-scion interaction, incompatibility is often due to:
a) pH mismatch
b) Genetic distance and biochemical mismatch
c) Poor fruit setting
d) Overwatering - Which is an ideal trait for rootstock in arid regions?
a) High fruit set
b) Deep rooting ability and drought resistance
c) Slow growth rate
d) High protein content - Which combination results in better performance of guava against wilt disease?
a) Psidium guajava on P. friedrichsthalianum
b) P. guajava on P. guajava
c) P. guajava on P. cattleianum
d) P. guajava on seedling rootstock
3: Graft Compatibility and Incompatibility
- Graft incompatibility is most commonly associated with:
a) Poor cambial contact
b) Genetic dissimilarity between stock and scion
c) Viral infection
d) Lack of chlorophyll - Which anatomical sign is often observed in incompatible grafts?
a) Discontinuity in vascular tissues
b) Excess callus development
c) High stomatal density
d) Increased fruit set - Delayed incompatibility is characterized by:
a) Immediate graft union failure
b) Initial success followed by decline over time
c) Cambial mismatch
d) Unsuccessful bud break - Incompatibility in citrus is frequently observed when scion is grafted on:
a) Carrizo citrange
b) Rough lemon
c) Cleopatra mandarin
d) Troyer citrange - The biochemical cause of graft incompatibility often includes:
a) Lack of starch
b) Mineral imbalance
c) Accumulation of phenolic compounds
d) Excess protein - Which grafting combination is typically incompatible?
a) Apple on M9
b) Kinnow on Carrizo
c) Pear on Quince without interstock
d) Guava on P. friedrichsthalianum - Which test is used to assess graft incompatibility?
a) IAA assay
b) Inarching test
c) Sugar accumulation test
d) Turgor pressure measurement - Which plant hormone may be involved in incompatibility signaling?
a) Cytokinin
b) Auxin
c) Ethylene
d) Abscisic acid - A compatible graft union shows:
a) Browning of tissues
b) Continuous cambial and vascular connection
c) Lenticel collapse
d) Root swelling - Which feature is most associated with successful grafting?
a) Low humidity
b) Unrelated plant families
c) Matching cambial layers
d) Different growth rates - Graft incompatibility in apples can be avoided by:
a) Using M7 stock
b) Using appropriate interstocks like M9
c) Pruning after grafting
d) Delaying budding - Which of the following species combinations is naturally incompatible?
a) Citrus × Apple
b) Apple × Pear
c) Citrus × Poncirus
d) Mango × Mango - What visual symptom indicates delayed incompatibility?
a) Excess chlorophyll
b) Union bulge or swelling at graft junction
c) Uniform growth
d) Enhanced yield - The presence of which compound at graft junction often correlates with incompatibility?
a) Tannins
b) Sucrose
c) Polyphenols
d) Nitrogen - What technique can help bypass incompatibility in pear on quince rootstock?
a) Chip budding
b) Bridge grafting
c) Use of interstock like Old Home
d) Soil drenching - Graft incompatibility may result in:
a) Increased flowering
b) Poor translocation of water and nutrients
c) High root vigor
d) Scion overgrowth - Which physiological process is disrupted in incompatible grafts?
a) Osmosis
b) Xylem and phloem continuity
c) Gametogenesis
d) Photosynthesis - Which grafting method minimizes incompatibility risk?
a) Patch budding
b) Veneer grafting
c) Inarching with juvenile material
d) T-budding - Which type of graft incompatibility shows visible symptoms within a few weeks?
a) Translocated incompatibility
b) Delayed incompatibility
c) Anatomical incompatibility
d) Hormonal incompatibility - Incompatibility may result from which genetic interaction?
a) Dominant lethal genes
b) Mutation
c) Genomic disharmony between rootstock and scion
d) Polyploidy - Which type of graft incompatibility shows sudden scion collapse years after planting?
a) Immediate
b) Delayed
c) Root-based
d) Cambial - Which anatomical layer plays a critical role in determining compatibility?
a) Xylem
b) Phloem
c) Cambium
d) Cortex - In mango, graft incompatibility is rarely observed due to:
a) Vigorous rootstock growth
b) Use of same species for stock and scion
c) Seasonal grafting
d) High humidity - The incompatibility between cherry and peach is primarily due to:
a) Genetic distance between species
b) High callus formation
c) Low temperature
d) Nutrient deficiency - Graft incompatibility can be reduced by:
a) Using older scion material
b) Selecting compatible stock-scion combinations
c) Delaying irrigation
d) Avoiding pruning
4: Physiological and Hormonal Aspects of Graft Union Formation
- Which hormone is primarily responsible for callus formation at the graft union?
a) Gibberellin
b) Auxin
c) Ethylene
d) Abscisic acid - During graft union, auxin is transported from:
a) Roots to leaves
b) Scion to stock
c) Soil to leaves
d) Cambium to phloem - The earliest physiological response after grafting is:
a) Lignification
b) Wound response and callus formation
c) Leaf unfolding
d) Root branching - Which tissue regenerates first at the graft union?
a) Phloem
b) Callus and cambial bridge
c) Xylem
d) Pericycle - Cytokinin promotes which process during graft healing?
a) Leaf drop
b) Cell division in callus tissue
c) Dormancy
d) Root elongation - The success of grafting is strongly influenced by:
a) Leaf senescence
b) Hormonal balance between auxin and cytokinin
c) Anthocyanin concentration
d) Starch degradation - What is the major role of ethylene in graft union formation?
a) Stimulates chlorophyll synthesis
b) Regulates cell expansion and stress response
c) Promotes root nodulation
d) Enhances pollen viability - Which physiological phase follows the callus proliferation during graft healing?
a) Leaf expansion
b) Vascular reconnection
c) Stomatal closure
d) Abscission - In compatible grafts, hormone transport resumes after:
a) One day
b) Vascular tissue reconnection
c) Leaf senescence
d) Phloem death - High auxin levels at the graft union induce:
a) Cambial death
b) Reduced photosynthesis
c) Cell differentiation and vascular tissue formation
d) Fruit drop - Which factor enhances hormone transport across the graft union?
a) Proper cambial alignment
b) Removal of all buds
c) Water stress
d) Defoliation - During graft union formation, which process is most energy-dependent?
a) Abscission
b) Cell proliferation and differentiation
c) Seed germination
d) Pollen tube growth - Which hormone inhibits cell division and may delay graft healing?
a) Auxin
b) Cytokinin
c) Abscisic acid
d) Brassinosteroid - What is the physiological significance of “callus bridge” at the graft site?
a) Prevents microbial invasion
b) Connects vascular cambium of stock and scion
c) Blocks hormone flow
d) Reduces transpiration - Synthesis of phenolic compounds at graft site is associated with:
a) Incompatibility
b) Defense and healing response
c) Inhibition of hormone transport
d) Breakdown of xylem - High C:N ratio in the scion favors:
a) Graft rejection
b) Effective callus formation
c) Graft incompatibility
d) Shoot dormancy - The reconnection of phloem tissues occurs:
a) Later than xylem
b) Earlier than xylem
c) Simultaneously
d) Does not occur - Which of the following enhances graft success rate by influencing hormone activity?
a) Ethrel
b) GA3
c) IBA (Indole-3-butyric acid)
d) Abscisic acid - Phytohormonal regulation during graft union affects:
a) Genetic transformation
b) Flowering induction
c) Cell cycle and tissue polarity
d) Trichome formation - Lignin deposition at the graft interface indicates:
a) Necrosis
b) Maturation of vascular tissues
c) Cambial mismatch
d) Disease onset - Proper temperature and humidity after grafting help in:
a) Reducing auxin
b) Leaf abscission
c) Promoting hormone-mediated cell activity
d) Stomatal closure - Graft success is enhanced when auxin application is made to:
a) Leaves of scion
b) Cambial area of stock or scion
c) Soil
d) Roots of stock - What is the main barrier for hormonal signal flow in unsuccessful grafts?
a) Vascular closure
b) Poor callus development and tissue differentiation
c) Low chlorophyll
d) Shallow graft cut - Which hormone is often responsible for early vascular connection in grafts?
a) Gibberellins
b) Brassinosteroids
c) Auxin
d) Abscisic acid - What happens physiologically when graft union fails?
a) High auxin transport
b) Cambial proliferation continues
c) Disrupted hormone transport and necrosis
d) Vascular system expands rapidly
5: Biochemical and Molecular Markers in Graft Union and Incompatibility Studies
- Which of the following biochemical markers is frequently elevated during graft incompatibility?
a) Starch
b) Phenolic compounds
c) Sugars
d) Lipids - The enzyme peroxidase activity at the graft union is often correlated with:
a) Successful grafting
b) Incompatibility and oxidative stress
c) Vascular continuity
d) Callus differentiation - Which molecular marker technique is most useful in studying genetic similarity between stock and scion?
a) HPLC
b) RAPD (Random Amplified Polymorphic DNA)
c) UV spectrophotometry
d) Atomic absorption - High polyphenol oxidase activity at the graft site often leads to:
a) Tissue browning and incompatibility
b) Chloroplast development
c) Sugar metabolism
d) Vascular bridge formation - Which molecular marker is considered most reliable for genotype confirmation in compatibility studies?
a) ELISA
b) SDS-PAGE
c) SSR (Simple Sequence Repeats)
d) NMR - One key role of phenolics in graft union is:
a) Increasing root respiration
b) Inhibiting cell division when accumulated
c) Enhancing auxin action
d) Stimulating vascular differentiation - Incompatibility often leads to accumulation of which metabolite class?
a) Amino acids
b) Secondary metabolites like tannins and flavonoids
c) Organic acids
d) Polysaccharides - Which enzyme’s elevated activity indicates stress response at the graft site?
a) Catalase
b) Amylase
c) Peroxidase
d) Phosphatase - In successful grafts, phenolic levels at the graft interface typically:
a) Increase over time
b) Decrease gradually as healing progresses
c) Remain unchanged
d) Spike repeatedly - The transcriptional analysis of which gene family helps assess compatibility?
a) MYB
b) Auxin-responsive genes (ARFs)
c) LEA proteins
d) Histones - Which analytical method is commonly used to quantify total phenolics in graft studies?
a) GC-MS
b) Folin-Ciocalteu assay
c) ELISA
d) Atomic absorption - What is the significance of lignin biosynthesis in graft compatibility?
a) Delays healing
b) Indicates maturation and mechanical strength of union
c) Prevents vascular bridging
d) Promotes incompatibility - Molecular markers help predict incompatibility by revealing:
a) Genetic divergence between stock and scion
b) Rootstock respiration
c) Scion leaf expansion
d) Hormone movement - The expression of which stress-related gene increases in incompatible grafts?
a) Rubisco
b) PR (Pathogenesis-related) genes
c) LEA
d) TIR1 - Which marker system offers co-dominant inheritance and high reproducibility?
a) RAPD
b) SSR
c) AFLP
d) SCAR - Which amino acid is considered a precursor of phenolic compounds contributing to incompatibility?
a) Alanine
b) Tyrosine
c) Methionine
d) Lysine - Which of the following is a molecular consequence of stock-scion genetic mismatch?
a) Reduced stomatal index
b) Altered gene expression at the union site
c) Excess chlorophyll
d) Increased wax deposition - Flavonoid accumulation at the graft union is usually a sign of:
a) Stress and possible incompatibility
b) Successful healing
c) Hormonal harmony
d) Cambial proliferation - Which technique can simultaneously assess gene expression and compatibility-related responses?
a) PAGE
b) RAPD
c) qRT-PCR (Quantitative Real-Time PCR)
d) Chromatography - Elevated peroxidase and polyphenol oxidase activity in the graft zone indicates:
a) Enhanced cell elongation
b) Tissue stress and incompatibility
c) Cambial bridge formation
d) Photosynthetic recovery - The phenylpropanoid pathway is primarily associated with:
a) Auxin degradation
b) Synthesis of phenolic compounds
c) Protein synthesis
d) Starch formation - Which combination is most likely to show elevated phenolic content and peroxidase activity?
a) Mango on mango
b) Pear on quince (without interstock)
c) Guava on guava
d) Kinnow on Carrizo - The main reason for using molecular markers in graft studies is to:
a) Measure hormone levels
b) Assess water content
c) Identify genetic compatibility
d) Analyze chlorophyll - In incompatible grafts, enzymes like PPO and POD lead to:
a) Auxin breakdown
b) Oxidative damage and necrosis
c) Cambial overgrowth
d) Vascular fusion - Which advanced omics approach can be used to study graft compatibility mechanisms?
a) Proteomics
b) Genomics
c) Transcriptomics
d) All of the above
