Principles of Plant Genetics and Breeding

Falconer, D.S., and T.F.C. Mackay. 1996. Introduction to
quantitative genetics, 4th edn. Longman, Harlow, UK.
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improvement in maize and sorghum. In: Proceedings
of the International Conference on Quantitative Genetics
(Pollak, E., O. Kempthorne, and T.B. Bailey, eds). Iowa
State University, Ames, IA.
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Part A
Please answer the following questions true or false:
INTRODUCTION TO QUANTITATIVE GENETICS 145
Outcomes assessment
1 Quantitative traits are more influenced by the environment than qualitative traits.
2 Quantitative traits are controlled by polygenes.
3 Heritability is a population phenomenon.
4 The specific combining ability of a trait depends on additive gene action.
5 Polygenes have distinct and distinguishable effects.
6 Quantitative variation deals with discrete phenotypic variation.
7 Quantitative traits are also called metric traits.
Part B
Please answer the following questions:
1 What is quantitative genetics, and how does it differ from qualitative genetics?
2 Give two specific assumptions of quantitative genetic analysis.
3 Describe additive gene action.
4 What is the heritability of a trait?
5 What is the breeders’ equation?
Part C
Please write a brief essay on each of the following topics:
1 Discuss the role of the environment in quantitative trait expression.
2 Discuss the concept of general worth of a plant.
3 Discuss the concept of intuitive selection.
4 Discuss the application of combining ability analysis in plant breeding.
5 Discuss a method of estimating heritability of a trait.
Henderson, C.R. 1963. Selection index and expected genetic
advance. In: Statistical genetics and plant breeding
(Hanson, W.D., and H.F. Robinson, eds). National
Academy of Sciences and National Research Council
Publication No. 982. National Academy of Sciences and
National Research Council, Washington, DC.
Hill, J., H.C. Becker, and P.M.A. Tigerstedt. 1998.
Quantitative and ecological aspects of plant breeding.
Chapman & Hall, London.
Holland, J.B. 2001. Epistasis and plant breeding. Plant Breed.
Rev. 21:27–92.
Lin, C.Y. 1978. Index selection for genetic improvement of
quantitative characters. Theor. Appl. Genet. 52:49–56.