Efficiency of breeding strategy where grandparents – but not parents – contribute equally to the breeding population

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Table III

Scenario B. Considerations of parents per grandparent (P_GP). Here the gain is given in percentage of that maximizing gain per year for different deviations from the optimal testing. “n.p.”means “value not possible”. PF is the proportion of plants selected as parents for the breeding population.

Parameter (main		At optimum P_GP			% of optimum annual genetic gain at the
scenario in parenthesis)					P_PG given below
	Value
		P _GP	PF	Annual gain, %	1^a	1.5	2	2.5	3	3.5	4	6
Narrow-sense heritability (0.125)	Main scenario	3	0.020	0.213	74	88	96	99	100	98	94	n.p.
	0.05	3	0.020	0.159	61	83	94	99	100	98	93	n.p.
	0.2	2.5	0.014	0.249	82	93	98	100	100	98	94	n.p.

Fixed costs per grandparent (100)	0	3.5	0.016	0.231	71	85	93	97	99	100	100	84
	200	2	0.020	0.186	80	95	100	99	91	68	n.p.	n.p.

Cost of parent (50)	0	6.5	0.022	0.250	64	78	85	90	94	96	97	n.p.
	100	2	0.020	0.186	83	97	100	90	n.p.	n.p.	n.p.	n.p.

Annual budget per grandparent (20)	10	1.5	0.060	0.129	98	100	n.p.	n.p.	n.p.	n.p.	n.p.	n.p.
	30	4	0.013	0.244	69	82	90	95	98	99	100	95
	40	5	0.011	0.262	66	79	87	92	95	97	99	100
	50	6	0.010	0.275	65	77	85	90	93	96	97	100

The base line parent balance strategy without the component of the among-family selection.