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Información > Pósters
Morphological and genetic variability in wild potato species from
northwest Argentina
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Clausen, AM1,
Ispizúa, VN1, Camadro, EL1,2,
Larrosa, F1.
1Unidad Integrada EEA Balcarce, INTA-FCA,
UNMdP. 2CONICET. C.C.276, (7620).
Balcarce, Argentina. |
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email:aclausen@balcarce.inta.gov.ar |
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Figure 1. Click on the picture to enlarge |
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Introduction
Populations of wild potato species identified as
S. infundibuliforme (ifd, 2n=2x=24; 2NBE)
and S. gourlayi (grl, 2n=4x=48; 4NBE) and probable
interspecific hybrids (grl-ifd; opl-ifd) were collected in a narrow
dry Andean gorge at 3600m known as Incacuevas in the province of
Jujuy. Morphological variability was detected in the accessions
collected (Fig. 1). |
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Materials and Methods
Twelve populations were collected as plants and
tubers in the site and accession of S. oplocense (opl),
S. gourlayi (grl) and S. Infundibuliforme
(ifd) from neighboring valleys were included in this study (Table 1).
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Click to enlarge |
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Table 1: Accessions studied.
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Accessions |
Species |
Coordinates
Lat. S-Long. W |
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Oka 4837 |
S. gourlayi |
24º 32' - 66º 12' |
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Oka 4314 |
S. gourlayi |
23º 37' - 65º 32' |
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Oka 7565 |
S. gourlayi |
23º 58' - 65º 38' |
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ClI 1705 |
S. oplocense |
23º 11' - 65º 19' |
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ClI 1706 |
S. oplocense |
23º 11' - 65º 19' |
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ClI 1707 |
S. gourlayi |
23º 00' - 65º 27' |
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ClI 1708 |
S. gourlayi x
? |
23º 00' - 65º 27' |
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ClI 1709 |
S. infundibuliforme x ? |
23º 00' - 65º 27' |
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ClI 1710 |
S. gourlayi |
23º 00' - 65º 27' |
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ClI 1711 |
S. infundibuliforme |
23º 00' - 65º 27' |
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ClI 1712 |
S. gourlayi x
? |
23º 00' - 65º 27' |
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ClI 1713 |
S. gourlayi x
? |
23º 00' - 65º 27' |
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ClI 1714 |
S. oplocense ? |
23º 00' - 65º 27' |
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ClI 1715 |
S.
gourlayi x
infundibuliforme? |
22º 59' - 65º 27' |
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ClI 1716 |
S.
gourlayi
x ? |
22º 59' - 65º 27' |
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ClI 1717 |
S. infundibuliforme |
22º 59' - 65º 27' |
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ClI 1718 |
S.
gourlayi |
22º 59' - 65º 27' |
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ClI 1720 |
S. infundibuliforme |
23º 03' - 65º 24' |
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The material was planted in a screenhouse, with a
variable number of genotypes of each accession. 36 morphological
characters (Table 2) were determined on 172 plants and the
results were analyzed by a Principal Components Analysis (PCA).
Chromosome numbers were determined on root tips using the standard
technique. Percentage of pollen viability was estimated according to
Alexander (1980) and 76 genotypes were screened for 2n pollen.
Controlled crosses were made for 362 combinations of genotypes on
selected genotypes. 5 flowers were pollinated per combination of
genotypes and styles were fixed in FAA (8:1:1), processed according to
Martin (1958) and microscopically observed with UV light. Fruit and
seed set were recorded. Table 2: Morphological characters
registered.
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1 Plant height |
19 Leaf color |
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2 Color of stem |
20 Leaf pubescence |
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3 Presence of wings |
21 Peduncle length |
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4 Leaf length |
22 Number peduncle forks |
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5 Leaf width |
23 Pedicel length |
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6 Length of terminal leaflet |
24 Pedicel length from base to articulation |
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7 Width of terminal leaflet |
25 Number of flowers/
inflorescence |
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8 Length petiole terminal leaflet |
26 Calyx length |
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9 Length primary lateral leaflet |
27 Length of calyx acumen |
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10 Width primary lateral leaflet |
28 Radius of corolla |
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11 Length petiolule primary lateral leaflet |
29 Width of corolla lobe at the base of corolla
lobe |
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12 Width second lateral leaflet |
30 Length of corolla lobe from base to acumen |
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13 Length second lateral leaflet |
31 Corolla acumen length |
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14 Number lateral leaflets |
32 Primary adaxial corolla color |
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15 Number interjected leaflets |
33 Secundary adaxial corolla color |
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16 Adaxial pubescence |
34 Anther length |
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17 Abaxial pubescence |
35 Style length |
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18 Color leaf veins |
36 Length of style exsertion |
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Table 3. Click to enlarge |
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Results and Discussion
Chromosome numbers were determined on a variable
number of genotypes and only tetraploids have been detected so far in
the probable hybrid populations. Variable results were obtained as a
result of the crosses performed; a high percentage of the combinations
were compatible in both directions (Table 3). Some combinations
did not produce seeds, indicating the probable existence of post-zygotic
barriers. Variable results for pollen fertility and a high number of
plants with 2n pollen were found (Table 4).
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Table 4. Pollen fertility and
2n pollen production.
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Species |
Accession |
Nº plants |
Fertility
(%) x range |
Nº plants
with 2n
pollen |
% 2n pollen 2n
x range |
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grl |
ClI 1710 |
11 |
80(87,5-73,6) |
11 |
7,3 (16,4-1,9) |
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grl |
ClI 1718 |
1 |
91,7 |
1 |
0,9 |
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grl? |
ClI 1712 |
3 |
76,9(80,9-73,5) |
3 |
7,5(8,7-5,7) |
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grl |
ClI 1707 |
6 |
67,3(80-34,8) |
6 |
4,8(7,2-2,5) |
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ifd |
ClI 1717 |
2 |
59,7(64,3-55,2) |
2 |
3,5(4-3,1) |
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Hybrid? |
ClI 1715 |
27 |
93,4(99,3-50,9) |
16 |
4,2(15,6-0) |
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Hybrid? |
ClI 1716 |
26 |
57,6(86,4-22,61) |
24 |
4,1(13,4-0) |
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Figure 2a y 2b. Click to enlarge
Figure 3. Click on the picture to enlarge |
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The morphological analysis of the entire data set
by means of PCA (Fig. 2a) revealed that only opl from outside
Incacuevas formed a group, overlapping with grl in a few cases.
The PCA performed with the mean values of each
accession (Fig. 2b) differentiated opl, grl and ifd.
Populations suspected to be hybrids as ClI 1715, with many plants with
a strong resemblance to ifd (Fig 3), clustered close to this
species, although the wide dispersion of individual plants of this
accession can be observed in Fig. 2a. The characters with a
major contribution to PCA axis I were width of primary lateral leaflet,
leaf width, width of second lateral leaflet, length of primary lateral
leaflet and length of petiolule of primary lateral leaflet.
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The majority of the accessions from Incacuevas,
presented intermediate values for these characters.
Conclusions
- The morphological variability observed in
the different populations of the wild potato species found in
Incacuevas may be the result of gene flow by hybridization,
considering the varying levels of pollen fertility, 2n pollen
production in diploids and tetraploids and the results of the
crosses performed and compatibility analysis.
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