The 23rd Session of the International Poplar Commission

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The 23rd Session of the International Poplar Commission

The Mechanism of 2n Pollen Formatiom in Populus × euramericana and P. × popularis

Speaker Jin-feng Zhang (Jennifer)
zjf@bjfu.edu.cn

Beijing Forestry University P.R.China

OUTLINE

1 Introduction 2 Materials and Methods 3 Results and Analysis 4 Discussion

1 Introduction
1.1 Polyploid breeding is an important part in poplar breeding ● ●

Triploid white poplar trees Triploid and aneuploid hybrids in Populus trichocarpa × P. deltoides



Triploidy were found in the cultivar poplar clones in section Aigeiros

1 Introduction
1.2 Mechanisms of 2n gamete formation in plant
● ● ● ● ●

Premeiotic doubling Omission of the first or second meiotic division Abnormal spindle Abnormal cytokinesis Nuclear fusion

FDR ( first division restitution ) : Contains non-sister chromatids SDR ( second division restitution): Contains two sister chromatids

1 Introduction
1.3 The objective of this study


Poplar can produce 2n gamete naturally or by artificial induction Elucidation of the cytological mechanisms of 2n gamete formation has been seldom in poplar. To detect and elucidate the mechanisms of 2n pollen formation in diploid poplar Results from this research may offer a more effective method for polyploid breeding in poplar in section Aigeiros.







2 Materials and Methods
2.1 Plant materials


Populus × euramericana Four male : EA1, EA2, EA3 and EA4 One female: A



P. × popularis The offspring of (P. simonii × (P.nigra var pyramidalis + Salix matsudana mixed pollen) ) One Male: P



The crosses
A × EA1, A ×EA2, A × EA3, A × EA4, A×P

2 Materials and Methods
2.2 Microsporogenesis observation 2.3 Flow cytometry analyses 2.4. Chromosome counting 2.5. SSR analysis

3. Results and Analysis
3.1 Cytological determination on 2n pollen formation

10

11

5

6

8

9

Table 1 The expected and observed rate of 2n pollen grains
Sporads Code of poplar Dyad Triad Tetrad Total Expected rate of 2n pollen % Observed rate of 2n pollen % χ2

EA1 EA2 EA3 EA4 P

539 163 689 2189 308

341 1818 682 4093 484

6629 5528 6354 1691 7308

7509 7509 7725 7973 8100

4.96 7.69 7.14 36.17 3.15

0.03 0.09 10.08 29.41 2.35

26.056**

** Indicated significant difference between expected rate of 2n pollen from sporads sample and the observed rate of 2n pollen from pollen sample at P< 0.01. The percentage were converted to arcsine data before χ2 test.

3. Results and Analysis
3.2. Detection of polyploid offspring of 2n pollen
Diploid 61# Diploid 61# Triploid 65#

Triploid

65#

0

50

Channels (FL2-A-

100

150

1.27)

200

250

Diploid 61#

Diploid 61# Triploid 73#

Triploid 73#

0

50

Channels (FL2-A-

100

150

1.27)

200

Diploid

61# 二倍体61#+ 61# Diploid 四倍体75# 75# Tetraploid

Tetraploid

75#

0

50

Channels (FL2-A-

100

150

1.27)

200

250

3. Results and Analysis
3.3. SSR determination on mechanism of 2n pollen formation
M ♂ ♀ M EA4♂ A
EA4 4x
75#

2x 2x 2x

4x 2x

2x

75#

♂ 4x M EA4 ♀ 75# 2x 2x 2x A

M ♂ ♀ 4x 2x 2x 2x
EA4 A 75#

(a) Primer: 14:
M
♂ ♀
EA4 A

(b) Primer: 41
4x 2x 2x 2x

(c) Primer: 47

75#

♂ ♀ 4x 2x 2x 2x
EA4 A 75#

M

(d) Primer: 68

(e) Primer: 105

Table 2 Segregation of alleles at loci where the male Populus ×euramericana.(Dode) Guinier parent EA4 is heterozygous

Code 14 41 47 68 105

SSR primer GCPM_2453-1 GCPM_3345-1 GCPM_3559-1 GCPM_432-1 ORPM_29

locus 1 2 3 4 5 6

EA4(♂) AB AB AB AB A0 B0

A(♀) CDE AC B A C0 DE

75#(4x) ABCDE ABC AB AB A0C0 B0DE

421(2x) 422(2x) 423(2x) ADE AC B A C0 BE ADE AC AB A C0 BE ADE AC AB A C0 BE

These letters do not necessarily correspond to discrete alleles(e.g. the “E”band for GCPM_2453-1 may be the non specific amplification ) and ORPM_29 primer detects two loci, 0 means a null allele.

3. Results and Analysis...
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