沙漠研究 19-1, 209- 212 (2009 )Journal of Arid Land Studies“Desert Technology IX ”
Refereed Paper

Study of the Morphological Variability of the Fruits of Some Coastal Date Palm
(Phoenix dactylifera L.) Cultivars in Tunisian Oases
Hanen MTAOUA1, Rim JAOUADI1, Ali FERCHICHI1
Abstract: This work consists in studying the variability of the fruits of sixteen coastal datecultivars at the stage “Tamar”, the last stage of maturity of the fruit, collected from the coastal
oases of Gabes and from the island of Djerba. Thus, thirteen parameters (qualitative andquantitative) concerning the pulpit and the seed of the fruit were the subject of this study.
Results show an important variability between the studied cultivars. The Principal Component
Analysis (PCA) makes possible to distinguish differences between cultivars. Fruits of thecultivars Ammari, Korkobi 2, Mermella and Rotbi are smaller than others of which values ofLth f, Wd f, Wg f and T p are lower than those of others. The PCA analysis shows a big
variability for alls morphological parameters.
Key words: Coastal cultivars, Date palm (Phoenix dactylifera L.), Morphological variability,
PCA analysis

1. Introduction:
The date palm (Phoenix dactylifera L.) forms the principal framework of the oasien ecosystem. InTunisia, we distinguish three types of oasis of which the coastal oases that contain only common varieties
as predicted by GID (2004) and Rhouma et al. (1996) of less commercial importance compared to thevariety Deglet Nour. The aim of this work is the recovery of these dates by studying the morphologicalvariability of the fruits of sixteen coastal date cultivars at the stage “Tamar”. Thus, thirteen parameters(qualitative and quantitative) concerning the pulpit and the seed of the fruit were the subject of this study.
2. Materials and methods
2.1. Plant material
Sixteen coastal date cultivars (coastal oases of Gabes and the island of Djerba), collected at the stage“Tamar”, were the subject of this study (Table 1).
Table 1. Designation of different studied varieties of Tunisian dates and their origins.

Number of cultivar
12
3
4
5
6
7
8
91011
12
13
14
15
16

1

Cultivar
AmmariBaht
BekrariBou Hattem
EguiwaGarn Gzel
HalwayKenta
Korkobi 1
Korkobi 2
Lemsi
Mermella
Nefzawi
Smitti 1
Smitti 2
Rotbi

CodeAmm.
Baht
Bek.
B. H.
Egw.
G. G.
Hal.
Kent.
Kork.1
Kork.2
Lem.
Mer.
Nef.
Smit.1
Smit.2Rot.

Institute of the arid areas, Medenine; Laboratory of arid and oases cropping.
Tel: +216 75 633 005; Fax: +216 75 633 006; E-mail: hanen-mtaoua@voila.fr.

Place of collection
DjerbaZarat
Elhamma
Chenenni
Dkhilt Toujène
Elhamma
Zarat
Elhamma
DjerbaZarat
DjerbaElhamma
Zarat
Elhamma
Zarat
Chenenni

2102.2. Morphological parametersThe morphological characterization of the fruit is carried out thanks to the thirteen parameters which
relate to the pulpit and the seed of fruit (Table 2).
Table 2. Morphological parameters studied and their designations.

Morphological parameter
Colour of the fruit
Texture fruit
Consistency of the fruit
Weight of the fruit
Weight of the seed
Length of the fruit
Length of the seedwidth of the fruit
width of the seed
Thickness of the pulpit
Weight of the seed/Weight of the fruit
Length of the seed/Length of the fruit
width of the seed/ width of the fruit

codeClTxt
Cst
Wg fWg s
Lth f
Lth s
Wd f
Wd s
Tp
R1
R2
R3

Unit
scale of notation
scale of notation
scale of notation
grgrmmmmmmmmmm-With: gr: gram; mm: millimetre.

3. Results and Discussion
3.1. Characterization of dates on the basis of morphological descriptors
The quantitative and qualitative parameters are different from a cultivar to another.
The weight of fruit varies from 11.28 mm for the cultivar Nef. to 4.34 mm for the cultivar Mer. The
cultivar Nef. has a fruit whose size is the most important, the average length of this fruit is 48.41 mm, it isa fruit of a elongated shape. The length of this date is similar to the variety Deglet Nour whose average
Lth f is of 45 mm as predicted by Rhouma et al. (1987).
The parameters R1 (weight of the seed / weight of the fruit), R2 (length of the seed/ length of thefruit) and R3 (width of the seed / width of the fruit) show significant variability between different cultivars.
The parameter R1 varies from 28.27 for the cultivar Mer. to 11.94 for the cultivar Hal. These differences
may be due to the characteristics of cultivars or the effect of pollination. Indeed, the absence or the poor
pollination gives a fruit of poor quality. The qualitative parameters (Txt, Cl and Cst) vary from a cultivar
to another.
Thus, even Kork.1 and Kork.2, which belong to the same variety they show differences, they havedifferent textures and consistencies: Kok.1 (from Djerba) is soft and honeyed while Kork.2 (from Zarate) is
dry and fibrous. Smit.1 and Smit.2 belonging to the same variety but different origin are also different:
Smit.1 is soft while Smit.2 is half-soft. This can be explained by the effect of cropping site of cultivars.
They may be close or far from shore with hot or humid or rainy or not climate as predicted byRasoazanakolona (2001).
3.2. Group and study of correlations between cultivars: Principal Component Analysis
The ACP, that describes and classifies all samples in smaller spaces dimensions, was applied to thematrix of morphological data. The first two axes of the ACP (1 and 2) express 71% of the total variability
estimated from the morphological characteristics.
In the plan 1-2, the correlation circle (Fig. 1a) shows the distribution of varying 2 groups ofcompounds highly representative according to axis F1:- Group1: the parameters R1, R2, R3 and Lth s;- Group2: contains settings T p, W f, Lth f and Lr f.
Groups 1 and 2 are negatively correlated in the plan 1-2. Thus, the representation of samples in thislandmark shows that: cultivars Amm., Mer. and Kork.2 reporting R1, R2 and R3 lower and low values ofLth f and Lth s and W f. These cultivars have smaller size and weight compared to others.

211a. Correlation circle.

b. Dispersion of different cultivars in the plan 1-2.

Fig. 1. Dispersion of individuals and variables made through the ACP analysis from morphological characteristics.

In general, we observe a big variability for all morphological parameters as shown by the correlation
circle; they are distributed far from the centre of the circle.
The analysis of the matrix (Table 3) confirms the results given by the circle of correlation. It showsthat parameter correlations have more or less importance. A positive correlation exists between Lth s and
R1and R2 and a strong negative correlation between the parameter Lth f and R2 and R3. Thus, a study of aparameter can give an idea on the other according to the synergy or the antagonism of parameters.
According to the distribution of the individuals in the plan 1-2 (Fig. 1b), we can notice that cultivars
were distributed into groups according to axes 1 and. We distinguish:- Group 1: formed of the cultivars collected from Zarat such as: Nef., Baht, Halw., Smit.1 (numberedon the plan 1-2: 13,1,7 and 15 respectively). These cultivars are, for the majority, soft.
- Group 2: contain cultivars collected from Elhamma such as: G. G., Kent. and Smit.2. (numbered on
the plan 1-2: 6, 8 and 14 respectively). These cultivars are, for the majority, dry to half-soft.
Concerning the cultivars resulting from Djerba and Cheninni, they are set far from the other groups.
The cultivar Rot., which is collected from Cheninni, differs significantly from all others cultivars; it has astrong negative correlation with axis F1 and a positive correlation with the axis F2. As for the cultivar B.
H. whose negative correlation is very high with the axis F2.
In fact, some cultivars of the same varieties are distributed differently, the cultivar smit.1 and smit.2of the variety Smitti belong to different groups from different origins (Zarat and Elhamma) in the plan 1-2of PCA analyze.
These results can reinforce the assumption of geographical sites effect on the morphologicalcharacterization of date palm fruits, knowing that Zarat is close to the sea compared to Elhamma.
Table 3. Correlation matrix of morphological parameters of Tunisian coastal dates studied.
WfWs

Wf
1

Ws

Tp

Lth f

Lth s

Lr f

Lr g

R1R2

1

Tp

0.51
0.44

0.14

1

Lth f

0.79

0.28

0.09

1

Lth s

0.74

0.47

0.06

Lr f

0.43

0.65
0.30

0.19

1

Lr g

0.66
-0.07

0.93
0.26
-0.50

-0.39

0.35

1

R1

-0.67

-0.32

-0.64

-0.44

-0.39

0.52

1

0.21
-0.18
-0.45
-0.30
-0.61
-0.74
0.56
-0.35
0.29
-0.09
-0.43
-0.29
-0.34
R30.55In bold, significant values (excluding diagonal) threshold alpha = 0.05 (bilateral test).

0.81

10.63

0.48

R2R3

0.53
0.27

11

212

But these results should not be taken as assertion, they must be reinforced by chemical and molecularanalyzes.
4. Conclusions
The morphological characterization of coastal dates revealed a significant variability. The differenceswere revealed between all cultivars for all morphological parameters (qualitative and quantitative ones) as
shown by the PCA analyse. The parameters have different correlations between them, some ones arecorrelated positively, others negatively.
Thus, the PCA analyze distinguish the differences between cultivars: Amm., Kork.2, Mer. and Rot.
These varieties have smaller sizes with values of Lth f, Lth s, Wg f and T p lower than those of othercoastal cultivars studied.
These differences appear between dates of the different varieties, but also within same varieties ofwhich the geographic origin are different. This can be explained by the effect of sites of cropping. The
cultivars can be near or far from coast, the climate can be heat or wet or rainy or not.
In fact, this morphological characterisation of date palm fruits is a preliminary study which can be
reinforced by others markers with more specificity as chemical and molecular markers.
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