Free Plant Breeding and Genetics MCQs with Answers
329 Plant Breeding and Genetics MCQs from Agriculture, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
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329 questions · page 12 of 17
- A. Heritability (b.s)
- B. Co-heritability
- C. Genetic gain
- D. Genetic advance
Explanation: Co-heritability is the ratio of genotypic covariance to phenotypic covariance between two traits.
Correct answer: Co-heritability222. Concept of combining ability as measure of gene action was first proposed by___________________?
- A. Wright (1951)
- B. Cavalli (1952)
- C. Mather (1956)
- D. Sprague and Tatum (1942)
Explanation: Sprague and Tatum introduced combining ability analysis in 1942, separating general combining ability from specific combining ability.
Correct answer: Sprague and Tatum (1942)- A. Thoday (1953)
- B. Hardy (1908)
- C. Salisbury (1940)
- D. Muller (1950)
Explanation: Thoday used the terms genetic flexibility and phenotypic flexibility to describe the capacity for genetic change and observable…
Correct answer: Thoday (1953)- A. Thoday (1960)
- B. Johannsen (1903)
- C. Allard (1957)
- D. Mather (1951)
Explanation: Johannsen developed the pure line theory in 1903 after showing that selection within a genetically uniform pure line cannot produce…
Correct answer: Johannsen (1903)- A. Griffing (1956)
- B. Yates (1947)
- C. Smith (1936)
- D. Kempt Horne (1957)
Explanation: Smith proposed the discriminant function in 1936 to combine information from several traits into a selection criterion.
Correct answer: Smith (1936)- A. Comstock and Moll (1963)
- B. Lemer (1954)
- C. Perkins (1971)
- D. Robinson (1948)
Explanation: Comstock and Moll are credited with distinguishing microenvironmental variation within a site from macroenvironmental variation among…
Correct answer: Comstock and Moll (1963)- A. Perkins (1968)
- B. Comstock and Robinson (1948)
- C. Hayman (1958)
- D. Jinks and Jones (1958)
Explanation: Comstock and Robinson proposed biparental mating in 1948 to generate segregating progeny from selected plants while retaining information…
Correct answer: Comstock and Robinson (1948)- A. Gene interaction
- B. Dominance
- C. Peliotropy
- D. Selection differential
Explanation: Pleiotropy, spelled “pleiotropy,” causes one gene to influence two or more traits, producing genetic correlation between them.
Correct answer: Peliotropy- A. Cytoplasm
- B. 2D
- C. 5D + 5d
- D. 1D
Explanation: Resistance to Hessian fly in wheat is associated with genetic factors on chromosome 5D, represented here by 5D + 5d.
Correct answer: 5D + 5d- A. Hays and limner (1950)
- B. Hull (1935)
- C. Allard (1955)
- D. Constock et al (1949)
Explanation: Comstock, Robinson and Harvey proposed reciprocal recurrent selection in 1949.
Correct answer: Constock et al (1949)- A. Jones (1920)
- B. Richy (1920)
- C. Hays (1919)
- D. East (1920)
Explanation: Convergent improvement was proposed by Richey in 1920, a method that combines desirable traits from different breeding populations through…
Correct answer: Richy (1920)- A. brim (1966)
- B. Jensen (1952)
- C. Jensen (1970)
- D. Russel (1978)
Explanation: Jensen developed the concept of diallel selective mating in 1970. Diallel mating involves crossing selected parents in a systematic…
Correct answer: Jensen (1970)- A. Brim (1966)
- B. Simmonds (1979)
- C. Giber (1953)
- D. Goulden (1939)
Explanation: Goulden first suggested single-seed descent in 1939, a method that advances one seed from each plant generation after generation to…
Correct answer: Goulden (1939)- A. All the above
- B. Multi lines
- C. Pure lines
- D. Inbreed lines
Explanation: Inbred lines and pure lines are homozygous, while a multiline is a mixture of several genetically distinct but individually homozygous…
Correct answer: All the above- A. Hetrozygosity
- B. Homogeneity
- C. Homozygosity
- D. All the above
Explanation: Prepotency is the ability of a parent to transmit its traits consistently to offspring, and this increases as homozygosity increases.
Correct answer: Homozygosity- A. Wheat
- B. Sorghum
- C. Barley
- D. Maize
Explanation: Maize is protandrous: its anthers shed pollen before the female stigma becomes receptive, which promotes cross-pollination.
Correct answer: Maize- A. Jones and Davies (1944)
- B. Devaries and Correns (1900)
- C. Bruce and Keeble (1908)
- D. Nilson (1900)
Explanation: Jones and Davis reported cytoplasmic male sterility in onion in 1944, establishing the practical basis for using CMS in hybrid-seed…
Correct answer: Jones and Davies (1944)- A. Allelic genes
- B. nuclear genes
- C. Non alleleic genes
- D. All the above
Explanation: Genetic male sterility is governed by nuclear genes, commonly a recessive allele at a nuclear locus, unlike cytoplasmic male sterility…
Correct answer: nuclear genes- A. 10.00 am
- B. 5.20 pm
- C. 1.15 pm
- D. 7.00 am
Explanation: In wheat, anthesis is commonly recorded as beginning at about 1:15 p.m. under the standard crop-physiology reference used in such MCQs.
Correct answer: 1.15 pm- A. Six stamens
- B. Eight stamens
- C. Four stamens
- D. None of the above
Explanation: A rice flower has six stamens, even though grasses often appear to have reduced floral parts.
Correct answer: Six stamens