Session 5. PERT and CPM exercise

Session guide: PERT and CPM exercise
PERT and CPM exercise: Developing salt-tolerant varieties of paddy

DATE
TIME
FORMAT	Plenary participatory lecture
TRAINER

OBJECTIVES

At the end of this session, participants will have had an opportunity to practise:

1. Drawing a project network.
2. Calculations involved in identification of the critical path and crashing of activities.

INSTRUCTIONAL MATERIALS

None.

REQUIRED READING

Exercise: Developing salt-tolerant varieties of paddy

BACKGROUND READING

Reading note: Network techniques

SPECIAL EQUIPMENT AND AIDS

Overhead projector and chalkboard

Session guide: PERT and CPM exercise

The previous session presented a conceptual basis for preparing a project network and the calculations relating to identification of the critical path and crashing of activities to reduce project duration. The purpose of this session is to provide an opportunity for participants to practice these calculations through an exercise.

Divide the participant group into three or four smaller groups to facilitate interaction. Distribute the exercise as well as the computation sheets. Let them all work on the same exercise.

Reconvene the plenary group and distribute and discuss the solution, and discuss clear whatever doubts participants might have.

PERT and CPM exercise: Developing salt-tolerant varieties of paddy

Among several research programmes initiated to develop appropriate technologies to combat the growing problem of salinity, developing salt-tolerant varieties may be the most important technological advance for low-cost management of agricultural production in the affected areas. In this context, a research programme was proposed to:

(i) identify salt-tolerant strains;

(ii) develop a high yielding, salt-tolerant cultivar;

(iii) test the cultivar in the National Testing Network, and get it released through the National and State Variety Release Committees; and

(iv) test the performance of the cultivar in farmers' fields to get feedback from the farming community.

To implement the research programme, some 20 activities were identified (Table 1) and three time estimates were collated, based on the opinions of many breeders with long experience in developing varieties.

Table 1 Project for development of salt-tolerant varieties of paddy

TASK	Activities			Estimates
	ID	Pred.	Succ.	to	tm	tp
Grow donor plants	a	-	b	16	20	24
Cross & harvest F1 seeds	b	a	c	4	5	8
Rear F1 plants	c	b	e	8	12	16
Procure chemicals, etc.	d	-	e	12	20	32
Determine polar stage; plant F1 anthers for induction	e	d, c	g	4	10	12
Prepare aseptic growth room	f	-	g	8	12	20
Plant calli; regenerate plants; screen for salt tolerance	g	e, f	h	4	8	12
Screen plantlets in culture solution for salt tolerance	h	g	i	4	5	8
Identify haploids; create diploids	i	h	j	4	5	8
Transfer plantlets to field for screening and seed production	j	i	k	8	12	16
Screen material at Network sites	k	j	I	12	20	25
Select homozygous lines for agro-edaphic environments	I	k	m	16	20	24
Test material in on-station trials	m	I	n	16	20	24
Data analysis	n	m	o	4	8	12
Nominate entries for National Screening Nursery	o	n	p	16	20	25
Promote entries to National Trials	p	o	q	30	40	50
Evaluate on-farm in farmers' fields	q	p	r	15	. 20	24
Farmers' Field Days	r	p	d1	3	4	5
Release of cultivar by Variety Release Committees	s	q	t	5	8	12
Overall analysis and report writing	t	s	-	10	12	15
Dummy	d1	p	s

Computation sheet 1 Project for development of salt-tolerant varieties of paddy

TASK	Activities			Events			Expected time
	ID	Pred.	Succ.	ID	Pred.	Succ.
Grow donor plants	a	-	b
Cross & harvest F1 seeds	b	a	c
Rear F1 plants	c	b	e
Procure chemicals, etc.	d	-	e
Determine polar stage; plant F1 anthers for induction	e	d, c	g
Prepare aseptic growth room	f	-	g
Plant calli; regenerate plants; screen for salt tolerance	g	e, f	h
Screen plantlets in culture solution for salt tolerance	h	g	i
Identify haploids; create diploids	i	h	j
Transfer plantlets to field for screening and seed production	j	i	k
Screen material at Network sites	k	j	I
Select homozygous lines for agro-edaphic environments	I	k	m
Test material in on-station trials	m	I	n
Data analysis	n	m	o
Nominate entries for National Screening Nursery	o	n	p
Promote entries to National Trials	p	o	q
Evaluate on-farm in farmers' fields	q	p	r
Farmers' Field Days	r	p	d1
Release of cultivar by Variety Release Committees	s	q	t
Overall analysis and report writing	t	s	-
Dummy	d1	p	s

Computation sheet 2: Network for project for development of salt-tolerant varieties of paddy

Notes: Incorporate estimates for expected time, earliest and latest start and finish times, and slack time. Indicate the critical path.

Computation sheet 3: Different paths through the network

Path	Time for completion (from events 1 to 20; in weeks)

Computation sheet 4: Earliest and latest start and finish times, and slack time estimates

TASK	ID	Earliest		Latest		Slack
		ES	EF	LS	LF	Start	Finish
Grow donor plants	a
Cross & harvest F1 seeds	b
Rear F1 plants	c
Procure chemicals, etc.	d
Determine polar stage; plant F1 anthers for induction	e
Prepare aseptic growth room	f
Plant calli; regenerate plants; screen for salt tolerance	g
Screen plantlets in culture solution for salt tolerance	h
Identify haploids; create diploids	i
Transfer plantlets to field for screening and seed production	j
Screen material at Network sites	k
Select homozygous lines for agro-edaphic environments	l
Test material in on-station trials	m
Data analysis	n
Nominate entries for National Screening Nursery	o
Promote entries to National Trials	p
Evaluate on-farm in farmers' fields	q
Farmers' Field Days	r
Release of cultivar by Variety Release Committees	s
Overall analysis and report writing	t
Dummy	d1

Computation sheet 5: Estimating the probability of completing the project

Activity in critical path	Time estimate		Standard deviation for each activity	Variance for each activity
	to	tp
Total variance

Calculate the probability of completing the project on the target date:

Looking at the table, the probability of completing the project by the target date is about __ %

Solution sheet 1. The network exercise on the project for development of salt-tolerant varieties of paddy

Figure 1 Activity times in the network of the project on salt-tolerant varieties of paddy

Solution sheet 2: Different paths through the network for the project on development of salt-tolerant varieties of paddy

Path	Time for completion (events 1 to 20; weeks)
1-2-3-4-5-6-7-8-9-10-11-12-13-14-15-16-18-19	229.3
1-2-3-4-5-6-7-8-9-10-11-12-13-14-15-18-19	245.1
1-5-6-7-8-9-10-11-12-1 3-14-15-16-18-19	195.4
1-5-6-7-8-9-10-11-12-13-14-15-17-18-19	195.4
1-4-5-6-7-8-9-10-11-12-13-14-15-16-18-19	195.4
1-4-5-6-7-8-9-10-11-12-13-14-15-17-18-19	195.4

Solution 4: Estimates of earliest and latest start and finish times and of slack time

TASK	ID	Earliest		Latest		Slack
		ES	EF	LS	LF	Total	Free
Grow donor plants	a	0.0	20.0	0.0	20.0	0.0	0.0
Cross & harvest F1 seeds	b	20.0	25.3	20.0	25.3	0.0	0.0
Rear F1 plants	c	25.3	37.3	25.3	37.3	0.0	0.0
Procure chemicals, etc.	d	0.0	20.7	16.6	20.7	16.6	16.6
Determine polar stage; plant F1 anthers for induction	e	37.3	46.6	37.3	46.6	0.0	0.0
Prepare aseptic growth room	f	0.0	12.7	33.9	46.6	33.9	33.9
Plant calli; regenerate plants; screen for salt tolerance	g	46.6	54.6	46.6	54.6	0.0	0.0
Screen plantlets in culture solution for salt tolerance	h	54.6	59.9	54.6	59.9	0.0	0.0
Identify haploids; create diploids	i	59.9	65.2	59.9	65.2	0.0	0.0
Transfer plantlets to field for screening and seed	j	65.2	77.2	65.2	77.2	0.0	0.0
Screen material at Network sites	k	77.2	96.7	77.2	96.7	0.0	0.0
Select homozygous lines for agro-edaphic environments	l	96.7	116.7	96.7	116.7	0.0	0.0
Test material in on-station trials	m	116.7	136.7	116.8	136.7	0.0	0.0
Data analysis	n	136.7	144.7	136.7	144.7	0.0	0.0
Nominate entries for National Screening Nursery	o	144.7	164.9	144.7	164.9	0.0	0.0
Promote entries to National Trials	p	164.9	204.9	164.9	204.9	0.0	0.0
Evaluate on-farm in farmers' fields	q	204.9	224.7	204.9	224.7	0.0	0.0
Farmers' Field Days	r	204.9	208.9	204.9	208.9	154.8	154.8
Release of cultivar by Variety Release Committees	s	224.7	232.9	224.7	232.9	0.0	0.0
Overall analysis and report writing	t	232.9	245.1	232.9	245.1	0.0	0.0
Dummy	d1

Solution sheet 5: Estimating the probability of project completion

Activity in critical path	Time estimate		Standard deviation for each activity	Variance for each activity
	to	tp
1,2	16	24	1.33	1.77
2,3	4	8	0.67	0.45
3,4	8	16	1.33	1.77
5,6	4	12	1.33	1.77
6,7	4	8	0.67	0.45
7,8	4	8	0.67	0.45
8,9	8	16	1.33	1.77
9,10	12	25	2.17	4.71
10,11	16	24	1.33	1.77
11,12	6	24	1.33	1.77
12,13	4	12	1.33	1.77
13,14	16	25	1.50	2.25
14,15	30	50	3.33	11.09
15,17	15	24	1.50	2.25
17,18	5	12	1.17	1.37
18,19	10	15	0.83	0.69
Total Variance			37.87

Calculating the probability of completing the project by the target date.

Looking at the table, the probability of completing the project by the target date is about 100%

TOTAL AND FREE SLACK ON THE NETWORK OF THE PROJECT ON SALT TOLERANT VARIETIES OF PADDY.

This training manual has been prepared as basic reference material to help national research trainers structure and conduct training courses on research management at the institute level. It is intended primarily for managers of agricultural research institutes in developing countries and for institutions of higher education interested in presenting in-service training courses on research management. The manual consists of ten modules, each addressing major management functions including motivation, leadership, direction, priority setting, communications and delegation. The four structural functions of management - planning, organization, monitoring and control - are covered in individual modules. The manual has been designed to support participatory learning trough case-studies, group exercises and presentations by the participants.