International Scholarly Research Notices

International Scholarly Research Notices / 2012 / Article

Research Article | Open Access

Volume 2012 |Article ID 326461 | 9 pages | https://doi.org/10.5402/2012/326461

Morphological and Pomological Diversity of Fig (Ficus carica L.) Cultivars in Northwest of Tunisia

Academic Editor: K. Aitken
Received02 Apr 2012
Accepted29 May 2012
Published18 Jul 2012

Abstract

The fig (Ficus carica L.) is one of the oldest fruit trees cultivated in Tunisia. Djebba region is located in the northwest of Tunisia. It is very famous by fig culture. Many specific fig genotypes are very appreciated locally and nationally. Taking into account these considerations, Djebba fig cultivars are subject of label products, namely, “Djebba figs.” This study was focused on fig germplasm characterization of 17 cultivars in Djebba region based on morphological and pomological traits. Results revealed a large variability within the local fig germplasms. The comprehensive analyses of all the data permitted to distinguish some particular genotypes as distinct cultivars, and groups of cultivars as polyclone varieties. It was possible to discriminate six distinct cultivars and two groups of multiclone varieties (Soltani and Thgagli) with different degrees of polymorphism. Hypotheses of homonymy and synonymy were suggested for some cultivars. The diversity is currently threatened by genetic erosion. Measure of conservation is necessary to be undertaken.

1. Introduction

The common fig (Ficus carica L., 2n = 26) belongs to the family Moraceae, with over 1400 species classified into about 40 genera. The genus Ficus contains about 700 species, mainly found in the tropics and currently classified into six subgenera [1]. Nowadays, the common fig grows wild in the Mediterranean Basin where it has been cultivated for its edible fruits for millennia in close association with olive and grapevine [2]. Three types of figs are grown commercially [3]: the common type that develops fruit parthenocarpically, the Smyrna type that requires pollination with pollen from caprifigs (caprification), and the San Pedro type that produces a first crop parthenocarpically and a second crop only after pollination. Total world fig production is over 1 million tons and 70% is produced in Turkey, Egypt, Greece, Iran, Morocco, Spain, and USA. Turkey produces nearly 25% of the total production [4].

In Tunisia, fig biodiversity is very high, and many niches are well suited for fig production. Despite its socioeconomic and historical importance, fig tree was considered as a secondary crop. Fig trees are grown all over the country, with more than 2,500,000 trees occupying about 33800 ha. The total annual production is about 27.000 mile tons [5]. Figs are mainly consumed as fresh fruits. A small portion is sun dried and little quantities are used for jam and alcoholic beverage production [6]. Tunisian fig cultivars are numerous and well adapted to local agroecological conditions [7]. Some are of the common type. Many others are of Smyrna type [8]. It should be stressed that several studies have reported the use of pomological traits in a number of Tunisian ecotypes collected from different zones [9]. Thus, 65 cultivars were described by Minangoin [10], 22 cultivars by Valdeyron and Crossa-Raynaud [11], and 28 by Lahbib [12]. It is noteworthy that a number of these cultivars have been destroyed as a consequence of the intensive urbanization in recent decades. Moreover, severe genetic erosion is also threatening the remaining germplasm. Thus, available information about the ancient landraces is very limited [6].

In order to preserve fig genetic resources, several prospections and alternative strategies for genetic resources management were considered. Pomological and morphological traits as well as molecular markers were used to analyse genetic diversity and characterize local cultivars [8, 1319]. Recently, various studies on fig genetic resources are continuing across the country. But no research results have been reported so far on northwest fig germplasm. This study is part of a project of the “Union Tunisienne de l’Agriculture et de la Pêche” aiming to establish a label to Djebba’s fig. The objectives are (i) identification of different fig cultivars grown in Djebba area and (ii) analysis of genetic diversity within the germplasm.

2. Materials and Methods

2.1. Plant Material and Study Area

This study concerned the region of Djebba (altitude, 700 m; latitude, 36° 40′N; longitude 9°0′E) located at the northwest of Tunisia. The climate is subhumid with mild winter and hot summer. Annual average temperature is around 20°C. Thermal amplitude is about 16.5°C in summer and 8°C in winter. Average annual rainfall is about 600 mm. The morphological and pomological variability was studied on adult fig trees of 17 local cultivars (one tree per cultivar) grown in this region (Table 1).


N°CultivarCodeType

1ZidiZD1Smyrna
2Zidi ArtabZD2Smyrna
3Soltani AbiadhSABSmyrna
4Soltani AhmarSAHSmyrna
5Thgagli AbiadhTABSmyrna
6Thgagli AkhdherTAKSmyrna
7NemriNMRSmyrna
8HemriHMRSmyrna
9BouhouliBHLSan Pedro
10WahchiWAHSan Pedro
11GaraïGRISan Pedro
12KhenziriKNZSan Pedro
13KhartoumiKRTSmyrna
14BoukhobzaBKBSmyrna
15ZerguiZRGSmyrna
16BouharragBHRSmyrna
17FawariFAWSmyrna

San Pedro produces first and second crops and Smyrna produces only second crop.
2.2. Morphological and Pomological Traits

Morphological and pomological parameters were chosen according to the fig descriptors [20]. On branches, 13 parameters related to the dimensions of shoots and internodes were measured (Table 2). For each cultivar, measurements were made after fall of leaves on six shoots per tree. For leaves, 16 parameters related to the lamina and petiole were measured on 20 mature leaves per tree and cultivar (Table 2).


TraitsCode

Branch
 Terminal bud length (mm)TBL
 Terminal bud diameter (mm)TBD
 TBL/TBD ratioTBL/TBD
 1-year-old shoot length (mm)S1Y
 Length of the 1st internode on S1Y (mm)L1N1Y
 Diameter of the 1st internode on S1Y (mm)D1N1Y
 Length of the 2nd internode on S1Y (mm)L2N1Y
 Diameter of the 2nd internode on S1Y (mm)D2N1Y
 2-year-old shoot length (mm)S2Y
 Length of the 1st internode on S2Y (mm)L1N2Y
 Diameter of the 1st internode on S2Y (mm)D1N2Y
 Length of the 2nd internode on S2Y (mm)L2N2Y
 Diameter of the 2nd internode on S2Y (mm)D2N2Y
Leaf
 Leaf shape (1: calcarate; 14: cordate)LS
 Shape of lobes (1: lyrate; 4: spatulate)SL
 Leaf color (1: light green; 12: dark green)LC
 Leaf margin dentation (1: undulate; 5: crenate)LMD
 Apex shape (1: truncate; 3: acute)AS
 Density of hairs (1: none; 7: pubescent/dense)DH
 Petiole color (1: light green; 6: pinkish)PC
 Leaf length (cm)LL
 Leaf width (cm)LW
 Petiole length (mm)PL
 Petiole diameter (mm)PD
 Depth of basal sinus (mm)DBS
 Depth of lateral sinus 1 (mm)DLS1
 Depth of lateral sinus 2 (mm)DLS2
 Depth of lateral sinus 3 (mm)DLS3
 Depth of lateral sinus 4 (mm)DLS4
Fruit
 Fruit weight (g)FW
 Fruit length (mm)FL
 Fruit diameter (mm)FD
 Neck length (mm)NL
 Neck diameter (mm)ND
 Ostiole diameter (mm)OD
 Fruit shape (1: spheroid; 10: pyriform)FS
 External color (1: violet black; 13: yellowish green)EC
 Skin cracks (1: cracked skin; 4: not cracked skin)SC
 Internal color (1: greenish white; 11: red)IC
 Fruit cavity (3: very small; 9: large)FC
 Skin thickness (mm)ST
 Flesh thickness (mm)FT
 pHpH
 Total soluble solids (°Brix)TSS
 Titratable acidity (%)TA

On fruits (second crop), 16 parameters related to the size, external and internal appearance, and juice quality were taken into account (Table 2). During the harvesting period, pomological measurements and chemical analysis carried out on samples of 20 mature fruits per tree and cultivar were randomly collected. Total soluble solids (°Brix) were determined with a digital refractometer, PR-101 ATAGO, and Norfolk, and titratable acidity (citric acid %) was determined by titrating fig juice with 0.1 M NaOH.

2.3. Statistical Analysis

For all parameters, analysis of variance (one-way ANOVA) was used to determine differences between cultivars. Comparison of the mean values was made using the Duncan’s multiple range test ( 𝑃 < 0 . 0 5 ). Multivariate relationships among cultivars were revealed through a principal component analysis (PCA) using a correlation matrix derived from the significant characters. The squared Euclidean distance was used to perform cluster analysis. Statistical analyses were computed using SPSS 13.0 statistical software.

3. Results

3.1. One-Way ANOVA

The average values of parameters measured on branches are shown in Table 3. Analysis of variance showed highly significant differences between cultivars for all parameters except terminal bud diameter (TBD). The study of morphological characteristics of fig tree shoots allowed the differentiation in biology of some cultivars such as Zidi (ZD1), Zidi Artab (ZD2), and Nemri (NMR). Moreover, the most discriminating variables were terminal bud length (TBL), 1-year-old shoot length (S1Y), and 2-year-old shoot length (S2Y).


CultivarTBL (mm)TBD (mm)TBL/TBDS1Y (mm)L1N1Y (mm)D1N1Y (mm)L2N1Y (mm)D2N1Y (mm)S2Y (mm)L1N2Y (mm)D1N2Y (mm)L2N2Y (mm)D2N2Y (mm)

ZD19.70def 5.271.82bcde 240.30a38.13a11.17bc 39.59a10.33abc 264.90a36.0514.38ab 39.06b 13.74ab
ZD27.73f5.331.46e166.65cd 24.27cde 13.61ab 21.67defgh 12.08a164.42bcd 30.2815.62a24.79bcd 15.41a
SAB8.57ef4.691.82bcde 125.29d15.19e7.69d 16.33fgh 6.51d131.00bcd 23.128. 27h18.52d 8.55fg
SAH8.30ef 5.311.58de 135.36cd 18.18cde 9.68cd 15.32gh 9.23bcd 144.83bcd 20.1711.43cde 20.58bcd 11.29cde
TAB11.29bcde 4.862.32a 157.08cd 22.76cde 8.32cd 19.01efgh 7.36de 152.32bcd 22.0010.11efgh 17.05d10.47def
TAK10.77cdef 5.152.12abc 169.80cd 18.64cde 9.03cd 19.94defgh 9.04bcd 122.24cd 18.6110.50efg 18.55d 10.22defg
NMR11.82bcd 5.921.98abcd 234.74ab 35.19ab 14.63a35.99ab 10.76ab 192.88b 27.0813.45bc 30.70abc 13.17bc
HMR13.07abc 5.952.29ab 164.16cd 23.68cde 9.13cd 23.65defgh 9.13bcd 172.96bc 24.2010.96def 27.44bcd 10.30defg
BHL15.15a6.482.33a181.04cd 20.44cde 10.44cd 25.70cdef 9.86bc 162.56bcd 28.0712.11cde 31.11abc 12.07bcd
WAH9.19def 5.091.80cde 155.29cd 25.03cde 8.75cd 26.73bcde 8.45cd 138.06bcd 30.078.99fgh 32.02ab 8.77fg
GRI11.15cde 5.182.14abc 169.08cd 24.32cde 9.82cd 24.28cdefg 9.90bc 145.97bcd 20.1510.14efgh 23.69bcd 10.37def
KNZ9.40def 5.251.80cde 187.30bc 26.62bcd 8.63cd 29.87bcd 9.12bcd 157.47bcd 26.478.38h 41.50a9.37efg
KRT9.72def 5.941.67cde 133.84cd 22.42cde 11.52bc 28.63bcde 10.41abc 127.76bcd 27.6712.65bcd 27.40bcd 11.86bcd
BKB10.03def 5.891.89abcde 147.82cd 17.46de 11.11bc 13. 81h10.03bc 122.07cd 22.6113.30bc 19.82cd 13.08bc
ZRG14.08ab 6.132.33a154.10cd 25.23cde 11.11bc 25.71cdef 10.72ab 147.05bcd 23.2313.07bcd 23.64bcd 13.04bc
BHR8.30ef 5.311.58de 161.59cd 18.18cde 9.68cd15.32gh 9.23bcd 144.83bcd 20.7012.67bcd 19.64cd 11.94bcd
FAW9.51def 4.542.10abc 151.43cd 27.78bc 7.73d33.77abc 6.62d 104.72d22.598.52gh 21.21bcd 8. 08g
F-value5.04**1.22NS3.93**3.12**4.03**3.82**6.15**5.76**3.42**1.72NS11.09**4.26**8.40**

Means in each column followed by the same letters are not significantly different at 𝑃 < 0 . 0 5 according to Duncan’s multiple range test.
S ignificant at 𝑃 < 0 . 0 5 ; s ignificant at 𝑃 < 0 . 0 1 ; NS: nonsignificant; TBL: terminal bud length; TBD: terminal bud diameter; TBL/TBD: TBL/TBD ratio; S1Y: 1-year-old shoot length; L1N1Y: length of the 1st internode on S1Y; D1N1Y: diameter of the 1st internode on S1Y; L2N1Y: length of the 2nd internode on S1Y; D2N1Y: diameter of the 2nd internode on S1Y; S2Y: 2-year-old shoot length; L1N2Y: length of the 1st internode on S2Y; D1N2Y: diameter of the 1st internode on S2Y; L2N2Y: length of the 2nd internode on S2Y; D2N2Y: diameter of the 2nd internode on S1Y.

The averages of characters related to leaf are shown in Table 4. Analysis of variance showed highly significant differences between cultivars for all parameters. The variability of leaf characteristics was very important and allowed the distinction between some cultivars for several parameters such as leaf shape, leaf margin dentation, and leaf dimensions (LS, LMD, LL, and LW), petiole color (PC), and the depth of basal and lateral sinus (DBS and DLS1, DLS2, DLS3, DLS4).


CultivarLSSLLCLMDASDHPCLL (cm)LW (cm)PL (mm)PD (mm)DBS (mm)DLS1 (mm)DLS2 (mm)DLS3 (mm)DLS4 (mm)

ZD112.84a 2.53e6.63de 5.00a 2.79abc 4.79cdef 3.00fg 29.45a 25.42a 99.05ab 7.67a46.37a 88.25ab 89.43a - -- -
ZD212.76ab 3.86a6.43def 4.05b 2.74abc 3.86ghi 3.48cdef 30.05a26.10a94.58abcd 7.20ab 53.18a77.72bc 76.64b - -- -
SAB11.85c 3.45abc 3.05h 2.20d 2.95a 2.60k3.95bcd 22.57cd 19.60cd 75.12fg 6.15c 11.00gh 70.07cd 71.10bc - -- -
SAH8.00d 3.00cde 3.30h 2.95cd 2.65abcd 4.70cdefg 5.05a 21.97cde 19.33cde 86.95bcdef 5.75cd 17.28fgh 86.23ab 88.36a 35.95bc 37.65bc
TAB7.25ef 3.25bcd 9.05ab 2.95cd 2.60bcd 4.60defg 3.85bcd 21.06cdef 19.23cdef 102.78 a5.63cd 25.24cdef 78.02bc 73.44bc 34.16bc 31.92cd
TAK12.25bc 3.85a 7.60bcd 2.70cd 2.65abcd 5.90ab 4.10bc 16. 71h16. 10g61. 32h5.08de 13.34gh 38.41 e39.97f- -- -
NMR7.70de 3.20bcd 7.30cd 3.25bc 2.95a3.60hij 2. 25h25.71b 22.34b 76.30fg 7.00b 22.78cdef 90.46a 93.01a40.54ab 41.02ab
HMR12.35abc 2.90cde 2. 60h2.45cd 2.85ab 5.30bcd 3.70bcde 20.08efg 18.07def 93.57abcde 5.64cd 11.10gh 69.87cd 67.80bcd - -- -
BHL12.85a2.95cde 2.95h 3.05cd 2.85ab 3.20ijk 3.50cdef 20.34defg 17.53efg 82.76def 5.57cd 18.88efg 59.02d 57.73de - -- -
WAH7.55def 2.90cde 2.90h 2.85cd 2.90ab 5.50abc 4.10bc 21.21cde 19.52cde 85.44cdef 5.65cd 9. 49h70.30cd 71.89bc 28.58cd 28.58de
GRI7.30ef 2.80de 3.55gh 2.35cd 2.85ab 3.00ijk 2.50gh 21.36cde 19.04cdef 84.70def 5.46cd 23.57cdef 67.44cd 68.47bcd 28.61cd 27.12de
KNZ11.90c 3.10cde 4.85fg 2.85cd 2.95a 5.10bcde 3.95bcd 18.93fg 17.29fg 81.21ef 4.68e48.17e 47.94ef - -- -
KRT6.40g 2.70de 8.85bc 2.10d2.40d3.20ijk 2.60gh 21.58cde 19.82cd 102.05a 5.86c 21.06def 92.12a 88.76a 46.41a45.92a
BKB2. 95h2.95cde 5.65ef 2.25cd 2.80abc 6.30a3.20ef 20.63def 18.86cdef 89.26bcde 6.12c 29.80bc 70.11cd 76.51b 38.81b 37.73bc
ZRG7.55def 3.75ab 5.15ef 3.00cd 2.60bcd 4.20fgh 3.35def 23.23c 20.03cd 65.44gh 5.93c 26.31bcde 65.03d 63.47cd 23.81d21.82e
BHR7.10f 3.70ab 8.65bc 5.00a2.50cd 4.30efgh 4.20b 18.20gh 17.26fg 80.92ef 5.81c 28.12bcd 71.07cd 70.33bc 31.13cd 31.04cd
FAW7.35ef 3.05cde 10.45a5.00a 2.70abc 2.90jk 5.20a26.18b 20.89bc 97.32abc 7.43ab 33.57b 95.03a91.55a 38.94b 40.49ab
F-value267.18**5.16**23.52**10.62**3.12**16.00**16.24**25.79**18.64**9.34**14.60**24.76**16.58**14.23**7.43**10.33**

Means in each column followed by the same letters are not significantly different at 𝑃 < 0 . 0 5 according to Duncan’s multiple range test.
S ignificant at 𝑃 < 0 . 0 5 ; s ignificant at 𝑃 < 0 . 0 1 ; NS: nonsignificant; —: absence of basal sinus; - -: absence of lateral sinus 3 and 4.
LS: leaf shape; SL: shape of lobes; LC: leaf color; LMD: leaf margin dentation; AS: apex shape; DH: density of hairs; PC: petiole color; LL: leaf length; LW: leaf width; PL: petiole length; PD: petiole diameter; DBS: depth of basal sinus; DLS1: depth of lateral sinus 1; DLS2: depth of lateral sinus 2; DLS3: depth of lateral sinus 3; DLS4: depth of lateral sinus 4.

The averages of characters related to fruit are given in Table 5. Analysis of variance showed highly significant differences between cultivars for all parameters. The most discriminating variables were fruit weight (FW) and fruit dimensions (FL, FD).


CultivarFW (g)FL (mm)FD (mm)NL (mm)ND (mm)OD (mm)FSECSCICFCST (mm)FT (mm)pHTSS (°Brix)TA (%)

ZD196.45a60.27a 60.52a5.31cd 14.70a12.74a3.79cdef 1.79hi 4.00a8.84abc 4.37bcdef 1.18de 12.13g 4.65ef 13.23g0.21fg
ZD251.83ef g 47.03de 43.90gh 7.71bc 11.80bc 5.81defg 3.90cde 1.86h 1.76f 9.95a3.10efgh 1.25cd 17.56abc 4.88cd 15.95ef 0.17h
SAB59.10cde 61.50a45.82fgh 14.43a 12.06bc 6.45cdef 4.50bc 11.95a 1.55f9.00abc 1.90h1.53ab 18.31ab 4.52gh 15.46f 0.25a
SAH44.45ghi 51.09bc 39.93i14.89a13.54ab 5.50efg 5.65a3.25f 3.45bcd 9.35ab 3.70defg 1.05e16.01cde 5.10a15.58f 0.18h
TAB62.20cd 42.75ef 53.65c 8.22b 2.70g12.00a3.75abc 7.85c 6.40a1.26cd 9.05h4.89cd 15.56f 0.20fg
TAK51.95efg 42.17f 50.26de 5.95cd 9.66cde 5.18fg 3.15efg 10.95c 2.90e 8.95abc 6.00ab 1.56ab 14.86de 4.45h 15.96ef 0.22bcdef
NMR82.36b 46.57def 58.62ab 7.34bc 3.00fg 4.50d 3.75abc 8.25bc 4.60bcde 1.48b 19.07a 4.82d 16.48de 0.23abcde
HMR57.83cde 58.12a 44.95fgh 10.90b 11.45bc 4.84g5.00ab 3.70e 3.45bcd 8.80abc 2.20gh 1.43bc 18.90ab 4.59fg 17.56c 0.25a
BHL64.53c 48.38cd 56.03bc 3.44d10.58cd 5.08fg 3.15efg 2.65g 3.90ab 4.65e 5.70abc 1.05e 16.00cde 4.91bcd 15.36f 0.21cdef
WAH41.67hij 43.50ef 44.27gh 5.92cd 10.97bcd 6.36cdef 3.40efg 11.40b 3.70abc 6.30d 2.80fgh 1.16de 17.85abc 4.95bc 19.02a0.23abc
GRI54.23def 45.86def 49.99de 3.91cd 7.55e7.12bcd 2.70g10.00c 3.60abc 3.05f 4.70abcde 1.05e 19.24a4.29i16.32de 0.21defg
KNZ44.27ghi 44.31def 47.34efg 5.21cd 10.42cd 5.78defg 2.85g 11.30bc 3.35cd 8.50bc 5.00abcd 1.54ab 12.13g 4.97bc 18.32b 0.23abcd
KRT52.77defg 46.36def 47.99ef 5.71cd 11.31bc 5.81defg 4.25bcd 10.35c 3.80abc 8.55bc 4.20cdef 1.19de 14.24ef 4.46h 17.20c 0.24ab
BKB34.54j35.20g43.81h 4.26cd 8.34de 5.59efg 3.55defg 11.90a 3.70abc 9.00abc 3.10efgh 1.72a11.34g 4.71e 15.48f 0.22bcdef
ZRG37.38ij 43.06ef 45.49fgh 6.85cde 2.70g1.85h 3.10de 6.65d 5.20abcd 1.63ab 15.45de 5.00ab 16.84cd 0.19gh
BHR46.87fgh 42.76ef 43.98gh 6.44cdef 3.15efg 1.40i3.80abc 2.00f2.70fgh 1.55ab 12.40fg 4.91bcd 17.00cd 0.21efg
FAW53.58defg 53.64b 52.99cd 6.34cd 11.78bc 6.41cdef 3.85cdef 2.15h 3.60abc 5.45de 4.10cdef 1.58ab 16.89bcd 4.55fgh 17.26c 0.25a
F-value26.00**26.30**28.16**21.32**5.50**23.00**10.46**977.45**23.24**29.54**6.12**13.13**21.22**46.17**31.75**10.00**

Means in each column followed by the same letters are not significantly different at P < 0.05 according to Duncan’s multiple range test.
S ignificant at P < 0.05; s ignificant at P < 0.01; NS: nonsignificant; —: neck less fruit.
FW: fruit weight; FL: fruit length; FD: fruit diameter; NL: neck length; ND: neck diameter; OD: ostiole diameter; FS: fruit shape; EC: external color; SC: skin cracks; IC: internal color; FC: fruit cavity; ST: skin thickness; FT: flesh thickness; TSS: total soluble solids; TA: titratable acidity.
3.2. Principal Component Analysis

Principal component analysis(PCA) was performed taking into account shoots, leaves, and fruits. The eigenvalues obtained by PCA indicate that the first three components provide a good summary of the data. They explained 51.91% of the total variability. The first component, PC1, had large positive loading for shoot length of the two years (S1Y and S2Y), lengths of the 1st, and 2nd internode on S1Y (L1N1Y and L2N1Y), diameters of the 1st, and 2nd internode on SY2 (D1N2Y and D2N2Y), depths of basal and lateral sinus (DBS, DLS1 and DLS2), leaf dimensions (LL and LW), fruit weight and diameter (FW and FD), and ostiole diameter (OD) and negative loadings for petiole color (PC), fruit external color (EC), and total soluble solids (TSS). It represented 26.46% of the total variation (Table 6). This component separated the cultivars Zidi (ZD1) and Nemri (NMR) from Soltani Abiadh (SAB), Thgagli Akhder (TAK), and Khenziri (KNZ) based on shoot length, fruit size, depth of sinus, and ostiole diameter. It allowed the distinction of cultivars Bouharrag (BHR) and Wahchi (WAH) from ZD1 based on petiole color, fruit size, and total soluble solids (Figure 1). The second component, PC2, explained 13.67% of the variability observed. It is positively correlated with fruit length and shape (FL and FS), fruit neck dimensions (NL and ND) and negatively correlated with terminal bud length (TBL), 1-year-old shoot length (S1Y), and fruit cavity (FC). This component allowed the distinction of cultivars Zergui (ZRG), Bouhouli (BHL), Garaï (GRI), KNZ, and TAK from SAB, Soltani Ahmar (SAH), and Hemri (HMR) on the basis of fruit shape, fruit neck, and cavity (Figure 1). The third component, PC3, accounted for 11.78% of the total variability estimated from shoots, leaf, and fruit traits. It is positively correlated to the apex shape (AS), fruit length (FL), and titratable acidity (TA), and negatively correlated to the internode diameter of shoots of the two years (D1N1Y, D2N1Y and D1N2Y, D2N2Y), shape of lobes (SL), depth of basal sinus (DBS), and pH. This component allowed the differentiation of cultivars Fawari (FAW), SAB, and HMR with thin shoots and acid fruits from cultivars Boukhobza (BKB), BHR, ZRG, and SAH presenting thick shoots and low acid fruits (Figure 1). The projection of cultivars in the 1–3 plot exhibited the distinction of some cultivars with particular traits such as ZD1 and Zidi Artab (ZD2) and others which are grouped together and having similar characters such as (SAB, WAH, and KNZ) and (BKB, BHR, and ZRG) (Figure 1).


Principal componentsPC1PC2PC3

Cumulative, %26.4640.1351.91
Proportion, %26.4613.6711.78

Character*Eigenvalue

TBL 0.01 𝟎 . 𝟓 𝟔 0.23
SY1 𝟎 . 𝟕 𝟏 𝟎 . 𝟒 𝟕 0.28
L1N1Y 𝟎 . 𝟖 𝟐 −0.22 0.34
D1N1Y 0.61 −0.24 𝟎 . 𝟒 𝟔
L2N1Y 𝟎 . 𝟔 𝟗 −0.19 0.53
D2N1Y 0.47 −0.38 𝟎 . 𝟓 𝟎
SY2 𝟎 . 𝟖 𝟎 −0.16 0.20
D1N2Y 𝟎 . 𝟔 𝟑 −0.16 𝟎 . 𝟔 𝟓
L2N2Y 0.45 −0.28 0.48
D2N2Y 0.61 −0.24 𝟎 . 𝟔 𝟔
SL −0.29 −0.08 𝟎 . 𝟓 𝟖
AS 0.02 −0.05 𝟎 . 𝟓 𝟕
PC 𝟎 . 𝟒 𝟏 0.50 0.00
LL 𝟎 . 𝟖 𝟒 0.32 −0.11
LW 𝟎 . 𝟖 𝟓 0.27 −0.19
PD 𝟎 . 𝟖 𝟎 0.38 −0.12
DBS 𝟎 . 𝟕 𝟒 0.06 𝟎 . 𝟓 𝟎
DLS1 𝟎 . 𝟔 𝟎 0.55 −0.05
DLS2 𝟎 . 𝟔 𝟎 0.54 −0.07
FW 𝟎 . 𝟕 𝟓 −0.04 0.43
FL 0.35 𝟎 . 𝟔 𝟐 𝟎 . 𝟓 𝟐
FD 𝟎 . 𝟔 𝟐 −0.40 0.48
NL −0.18 𝟎 . 𝟕 𝟒 −0.09
ND 0.41 𝟎 . 𝟔 𝟕 0.18
OD 𝟎 . 𝟕 𝟒 −0.09 0.20
FS −0.01 𝟎 . 𝟖 𝟓 0.00
EC 𝟎 . 𝟓 𝟕 −0.19 0.25
FC 0.10 𝟎 . 𝟕 𝟎 0.07
pH 0.04 −0.05 𝟎 . 𝟑 𝟓
TA −0.28 0.17 𝟎 . 𝟕 𝟏
TSS 𝟎 . 𝟓 𝟎 −0.02 0.16

S ee Table 2.
3.3. Cluster Analysis

Morphological and pomological analysis based on different characters showed high polymorphism with 17 fig cultivars. The dendrogram based on squared Euclidian distance clustered cultivars into five major groups (Figure 2). The first cluster was constituted with three cultivars: Zidi, Zidi Artab (ZD2), and Nemri (NMR). ZD2 was the most divergent from the other cultivars ( 𝑑 = 2 0 ). It is characterized by long internodes, spatulate, and large leaves, deep sinus, and acid fruit juice. The cultivars ZD1 and NMR meet at d = 15.9. They shared the long shoots, large fruits size, and leaves with serrate margin dentation. The cultivar Soltani Abiadh (SAB) formed the second cluster at d = 16.9. This cultivar had the shortest shoots, flattened buds, and cordate leaves with apex acute. The fruits were very long, crackled with high acid juice. The third group, detached at d = 15.9, was constituted with the unique cultivar Fawari (FAW). It is distinguishable, particularly, by short vegetative shoots and internodes, flattened buds, and dark green, large and crenate leaves, with deep sinus and yellow petiole. Fruit shape was oblate producing high acid juice. The cultivar Soltani Ahmar (SAH) formed the fourth cluster at d = 12.85 of the remaining genotypes. It has short and thin shoots with flattened buds. The fruits were relatively small, purple with very thin skin, and give low acid juice with high pH. The leaves were pubescent, serrate with widened lobes and rounded apex. The fifth group consisted of 11 cultivars with a maximum internal dissimilarity level of 10. This cluster was divided into three subgroups. The first subgroup, detached at d = 10, comprised the cultivar Thgagli Akhder (TAK). It is distinguished essentially from the remaining genotypes by small leaves with spatulate lobes, shallow sinus, and short petioles. The second subgroup contained the cultivar Bouharrag (BHR) associated with a level d = 7.85 to the three cultivars Thgagli Abiadh (TAB), Boukhobza (BKB), and Khartoumi (KRT). They are characterized particularly by green leaves with widened lobes, fruits oblate, and sweetened juice. The third subgroup consisted of six cultivars with a maximum internal dissimilarity level of 7.61. Two subsets were identified in this third subgroup. Subset 1 composed of cultivars Garaï (GRI) and Bouhouli (BHL) which associated between them at high level of similarity (d = 2.37) and rejoined the cultivar Zergui (ZRG) at d = 7.61. These cultivars presented conical buds, light green cordate leaves, and oblate fruits without neck. Subset 2 composed of cultivars Khenziri (KNZ), Wahchi (WAH), and Hemri (HMR) having cordate leaves with widened lobes and serrate margin dentation, acute apex, and yellowish green petiole. The fruits give a sweetened juice. WAH and KNZ have the highest level of similarity observed (d = 0.71). The averages values of their main characteristics were similar.

4. Discussion and Conclusions

Morphological and pomological traits considered in this study showed a large variability for Djebba figs. Among the 45 variables analyzed, those of high discriminating level were leaf dimensions, shoot dimensions, petiole color and dimensions, depth of sinus, fruit shape and color, fruit weight and dimensions, ostiole diameter, and juice acidity. Results of the PCA based on shoots, leaf, and fruits traits showed that 51.91% of the total variability is accounted by the three PCs. Studies based on morphological and pomological traits conducted for pomegranate and peach founded, respectively, 49.29% [21] and 63% [22] of the total variability. Characters related to shoots, leaf, and fruits were powerful for studying the genetic diversity of domestic fig in Djebba. Results showed that, among these characters, some were good criteria for discriminating between cultivars. Similar results were reported by Salah et al. [9] in fig collection in the oasis of Nefzaoua and by Chatti et al. [13] in fig collection in Chott Mariem. In addition, morphological study based on the characteristics of fig trees has shown that the first three axes of the PCA amounted to 71.7% and 81.9% of the total variability, respectively, for leaves and fruit traits [15].

The cluster analysis showed high degree of diversity in the germplasm of Djebba fig. Among the cultivars with the same names, there is a similarity between Soltani Abiadh (SAB) and Soltani Ahmar (SAH) and between Thgagli Abiadh (TAB) and Thgagli Akhder (TAK). However, the levels of similarity observed were not always high enough to believe that they are synonymous. Both cultivars Soltani have almost the same characteristics of shoots and leaf and differed mainly by the fruit external color. Both cultivars Thgagli have a significant similarity in terms of shoots and fruit, while they have a divergence in leaf and petiole. Thus, for Soltani and Thgagli, it seems to be “polyclones cultivars” or “multiclones cultivars.” Both cultivars Zidi and Zidi Artab have many differences that were focused on shoots strength developed during the two years. Also, differences were noted for leaves and fruits. The hypothesis of homonymy between these two cultivars could be proposed.

Significant similarities were observed among the cultivars Wahchi (WAH), Khenziri (KNZ), and Hemri (HMR) and between Garaï (GRI) and Bouhouli (BHL) for all morphological and pomological traits. Thus, it seems to be a case of synonymy between these cultivars.

The characters adopted in this study could be used to establish a catalog of local fig cultivars. The concordance between the results of PCA and cluster analysis showed that morphological and pomological analysis can provide reliable information on the variability in fig tree. The overall analysis of all traits brings out a wide diversity in plant material that may have important implications for genetic resources management. This diversity could be due to the antiquity of the culture in this mountainous region and particular cultural practices [7]. More interest has been focused on the diversity since it was known that the domestication of fig tree occurred independently in different areas especially around the edge of the Mediterranean. Thus, it is very interesting to conduct the proper management of these genetic resources. This can be addressed by different tools such as the establishment of ex situ collections. The on-farm conservation can ensure the sustainability of these resources. It is also possible to explore the techniques of tissue culture as an alternative as future protocols for in vitro micropropagation and even cell-cultured fig are already developed [2326]. Further studies are needed involving chemical, biochemical, and molecular markers [14, 16, 17, 19]. They would clarify the genetic variation at the molecular level in these cultivars.

Acknowledgments

This study is part of research program of the Research Unit on Agrobiodiversity (UR03AGR04) financed by the Ministry of Higher Education, Scientific Research and Technology (Tunisia). Authors would like to thank Mrs. W. Brini for data analysis and technicians and farmers for their efficient collaboration.

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Copyright © 2012 Badii Gaaliche et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


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