Plant Breeding Methods (CS, HS 541)

Exercise 9 – G × E, Index Selection, Disease Resistance

Give complete answers, but be brief and specific. Show your work.

20 points total

1. If you had six genotypes tested in 5 environments such that each genotype was ranked according to its performance in that particular environment, which genotype(s) would you select to release and why? Rank the order of genotypes based on performance over all environments.

	E1   E2   E3   E4   E5
	G2   G6   G3   G2   G4
	G4   G3   G5   G5   G2
	G5   G2   G2   G3   G3
	G3   G1   G1   G6   G5
	G1   G5   G4   G4   G1
	G6   G4   G6   G1   G6

2. Of those shown below, which family has the best

a. performance for yield?

b. stability of performance?

	           Yield(g/plant)
	Family Mean   b   sGE(A)  sGE(W)
	  1     27   1.0    0.2    0.6
	  2     36   0.8    1.5    0.6
	  3     34   0.7    0.5    0.6
	  4     35   1.1    0.3    0.6
	  5     32   0.9    0.6    0.6

c. Which family would you select considering all 3 of the measures shown?

d. Why?

 

3a. Calculate the following selection indices for the families shown below (only 5 of the 300 families tested are shown; best possible quality rating is 9, best possible disease rating is 0):

Independent Culling Level (ª check), Simple Weighted (35% yield, 40% quality, 25% disease), Elston’s Weight-Free, Baker’s Standard Deviation, and Average Rank.

      Yield  Rating   Corrected values    Index for selection
Plant ($/A) Qual Dis Yield Qual  Dis    ICL  SW   EWF  BSD  AR
  1    220    1   0  _____ _____ _____ ____ ____ ____ ____ ____
  2     35    9   4  _____ _____ _____ ____ ____ ____ ____ ____
  3     85    4   6  _____ _____ _____ ____ ____ ____ ____ ____
  4    170    8   2  _____ _____ _____ ____ ____ ____ ____ ____
  5    115    7   1  _____ _____ _____ ____ ____ ____ ____ ____
Range 30-300 1-9 9-0
Check  170    7   2
Worst   21    1   7
SP      23   1.8 2.1

b. Which family is the best and which family is worst, considering all three traits?

c. Why?

 

4a. What are four strategies for deploying resistance to diseases?

b. What are three ways disease resistance can be inherited?

c. What are three factors to consider when evaluating germplasm accessions for disease resistance?

 

5. What kind of a project leader would you like to be (in terms of your personality and the way you would treat your team members)? Would you like to run a large program from the office, or lead a small team while personally working in the greenhouse, laboratory, and field?