Bavarian State Research Center for Agriculture

Institute for Crop Science and Plant Breeding

50%

60%

70%

80%

90%

100%

combination

I

combination

IIa

combination

I

combination

IIb

location PU location AES

Cross-pollination rates

90.0%n=107

79.6%n=104

94.3%n=88

90.7%n=43

vertical line = standard deviation

Cross-pollination rates

90.0%n=107

79.6%n=104

94.3%n=88

90.7%n=43

vertical line = standard deviation

R² = 0,9176

1

2

3

4

5

6

7

8

9

1 2 3 4 5

Vitality during germination and seedling cultivation

(scoring marks, 1 = very weak to 9 = very strong)

R² = 0.918

I1-lines

2012

I2-lines

2013

I3-lines

2014

I4-lines

2015/16

vertical line = standard deviation; n = 8

(highly) inbred parents

open pollination

Seeds produced by cross-pollination

plant population in the field

seed fraction F1 > inbred

lower vitality, reduced growth

inbred descendant

F1-

In

breed

Michael Penzkofer, Stefan Seefelder, Heidi Heuberger

What is the percentage of cross-pollinated seeds respectively inbred seeds in cross-pollinated populations? Is an inbreeding depression identifiable for inbred lines, that is, do inbred plants exhibit lower vitality?

A

B

A

B

A B

Contact:

Bavarian State Research Center for Agriculture (LfL),

Institute for Crop Science and Plant Breeding

(IPZ3d), Vöttinger Str. 38, 85354 Freising,

Michael.Penzkofer@LfL.bayern.de, www.LfL.bayern.de.

• Selected va ler i an p l an ts (e l i tes) w ere propagated in -v i t ro (c loning ) .

• Homozy gous ly present DNA - based marker bands ( AFLP) w ere examined in the f i rst inbred generat ion ( I 1) .

• Si x e l i tes w ere ident i f ied that d i f fer in at least one h omozyg ous ba nd an d w ere used in three pa i r combinat ions ( I - I Ia / I Ib) .

• The mat ing c lones w ere p lant ed together in a poly - cross - system at two locat ions (PU - AES) .

• The seeds w ere taken separate ly f rom each p l ant an d e leven descendants f rom each p lant w ere analyzed .

• In seve ra l s teps , inbred l ines w ith d i f ferent leve ls of inbreeding ( I 1 t o I 4) w ere generated .

• A t each leve l of inbreeding a performance test w as carr ied out in the f ie ld , eva lu at ing the character ist ics e . g . v i ta l i ty dur ing germinat ion an d seedl ing cu lt ivat ion, crop coverage and v i ta l i ty in f ie ld , as w el l as rootstock w eight .

B

A

References: BECKER, B., 2011: Pflanzenzüchtung. Eugen Ulmer, Stuttgart BERNÁTH, J., 1997: Cultivation of Valerian. In HOUGHTON, P. H. (ed.), Valerian The Genus Valeriana, harwood academic publishers, United Kingdom, 77-100 HEEGER, E. F., 1956: Handbuch des Arznei- und Gewürzpflanzenbaues. Deutscher Bauernverlag, Berlin.

The observed high cross-pollination rates show the preference for cross-pollination, however autogamy is possible. (Similar reported in HEEGER, 1956 and BERNÁTH, 1997).

Thus, the first and important condition for a hybrid variety from open pollination, without male-sterility system would be met.

The detected inbreeding depression in inbred lines means that possibly formed inbred descendants will 'disappear' in field, saying that they will take a small fraction in the harvested material.

Hybrid-breeding can only be exploited fully, if inbred lines are used (BECKER, 2011). Therefore, another inbred step in the F1 hybrid seed production will probably create plants with a much higher inbreeding depression.

Basically the validity applies only for the tested clone combinations. Most likely, other clones or lines will behave similarly; however, in the end, the cross pollination rate of the developed hybrid variety must be determined.