Principles of Plant Genetics and Breeding

366 CHAPTER 19
Frey, K.J. 1959. Yield compensation of oats II: Effect of nitrogen
fertilization. Agron. J. 51:605–608.
Lee, E.A., A. Ahmadzadeh, and M. Tollenaar. 2005.
Quantitative genetic analysis of the physiological processes
underlying maize grain yield. Crop Sci. 45:981–987.
Milach, S.C.K., and L.C. Federizzi. 2001. Dwarfing genes in
plant improvement. Adv. Agron. 73:35–65.
Rasmusson, D.C., and B.G. Gengenbach. 1983. Breeding for
physiological traits. In: Crop breeding (Wood, D.R., ed.),
Part A
Please answer the following questions true or false:
References and suggested reading
Outcomes assessment
pp. 231–254. American Society of Agronomy, Madison,
WI.
Rosielle, A.A., and J. Hamblin. 1981. Theoretical aspects of
selection for yield in stress and non-stress environments.
Crop Sci. 21:943–946.
Simmonds, N.W. 1979. Principles of crop improvement.
Longmans, New York.
Worland, A.J. 1996. The influence of flowering time genes on
environmental adaptability in European wheats. Euphytica
89:49–57.
1 All yield is biological, but all yield is not economic.
2 Sinks are exporters of substances.
3 Biomass is the yield per unit area of the grain.
4 The higher the harvest index, the more efficient the plant is in directing assimilates to the part of the plant of economic value.
5 Lodging may occur at either the root or stem levels.
6 Grain shattering occurs only in legumes.
7 Most sorghum cultivars in the USA are two-dwarfs.
8 The dwarfing gene in wheat is designated Rht.
9 A bush-type cultivar is indeterminate in growth form.
Part B
Please answer the following questions:
1 There are two types of lodging: …………….. or …………………….
2 Give the genotype of three-dwarf sorghum.
3 Distinguish between single-dwarf and double-dwarf sorghum cultivars.
4 ……………………………………. is the proportion of the plant that is of economic value.
5 What is yield?
6 Distinguish between economic yield and biological yield.
7 What is yield potential?
8 Define harvest index.
Part C
Please write a brief essay on each of the following topics:
1 Discuss the genetics of dwarfing in sorghum.
2 Distinguish between determinate and indeterminate growth in plants.
3 Discuss the importance of lodging resistance in crop production.
4 Discuss the concept of plant ideotype.
5 Discuss the concept of yield components.
6 Discuss the importance of yield stability in cultivar development.
7 Discuss the concept of yield component composition.