Important ARS Questions on Generation Mean Analysis

 

1. What is generation mean analysis? Give its merits and demerits.

2. What are the different components of genetic variance? How will you estimate these using a 3-parameter model? For varietal improvement programmes, which of the genetic variance component is more useful and why?
   (ARSE, 1984)

3. (a) What are the components of continuous variation.

(b) Illustrate how a knowledge of genetic parameters estimated from means and variances is helpful in designing a suitable breeding strategy?

(c) The following genetic parameters were estimated using generation means. Digenic epistatic model was found adequate to explain the variation.

    m  d  h  i  j  l

    54.7** 4.9* –2.9* –1.9* –3.5* 8.4**

(i) Extract the relevant genetic information.

(ii) Are these estimates biased due to linkage? Justify.

(iii) Can heritability be estimated from the above data. Justify your answer.

(ARSE, 1986)

4. Describe briefly various models used for the estimation of gene effects in generation mean analysis.

5. Give in brief the comparison of six and five parameter models of generation mean analysis.

6. Discuss the role of scaling test in generation mean analysis. How does it differ from joint scaling test?

7. Write short notes on the following :
   (i) Scaling Test
   (ii) Test for Epistasis
   (iii) Joint Scaling Test
   (iv) Generation Mean Analysis

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8. Differentiate between the following :

(i) Six parameter model and three parameter model

(ii) Scaling test and Joint scaling test.

9. Describe briefly main features of six parameter model of generation mean analysis.

10. What are main features of five parameter model of generation mean analysis.

11. Write short note on the following :
    (i) Heritable-fixable variance
    (ii) Heritable Non fixable variance
    (iii) Degree of dominance
    (iv) Duplicate epistasis

12. Give contribution of following scientists :
    (i) Hayman
    (ii) Jones
    (iii) K. Mather
    (iv) Cavalli