Phenotypic polymorphism, pomological and chemical characteristics of some local varieties of fig trees (Ficus carica L.) grown in Eastern Morocco

The fig tree (Ficus carica L.) is one of the earliest fruit trees cultivated in Morocco, especially in the north-eastern region; which is growing inextricably linked to our social and cultural heritage. This study concerns morpho-pomological and chemical parameters of five local fig varieties, namely: Aounk Hmam “AH”, Chetoui “CH”, Bounacer “BN”, Ghoudane “GH”, and Malha “MA”. Significant differences were observed among the studied fig cultivars for some of the parameters investigated. In particular, the average fruit weight that ranged from 29.72 g to 58g for MA and AH respectively. At the ripening stage, fruits “MA” show the best skin cracks, while fruits "AH” are distinguished by their ease of peeling.In terms of titratable acidity, “AH” has the lowest value, while “CH” has the highest level. For the sweetest and tastiest variety of figs, Brix readings (expressed as total soluble solids content) registred range between 27 35% respectively for the MA and GH . According to the results of the parameters evaluated, particularly the acidity and the Brix index, the best varieties worthy of consideration from an agricultural and industrial point of view are "AH" and "CH" cultivars.


Introduction
The common fig (Ficus carica L., 2n = 26) belongs to the family Moraceae with more than 800 species [1], native to western Asia and the eastern part of the Mediterranean regions [2,3]. It was one of the first Mediterranean fruit species to be domesticate [4,5].The fig and olive trees are among the oldest domesticated trees in Morocco's northern region (Rif) [6]. The farmers involved in this project led by the cooperative "Gharmawne" will benefit from support equipment, training and supervision. In partnership with the municipality and other agricultural creators, this cooperative organizes each year the Aghbal festival of figs, a socio-economic event that aims to bring together consumers and producers of figs in eastern morocco. This event is held every year during the last weekend of August. The festival is an opportunity to promote the commercialization of figs and fig's derivative products, to encourage the innovation of small producers in this sector, and to show the natural and cultural assets of this region. The local fig germplasm has not been subjected to intensive plant selection programs; as a result many fig populations and ecosystems had a great genetic diversity, which must to be fully exploited by its identification and classification [9].The fig has a wide geographical distribution in the country and is well-known for its high commercial value and best fruit flavor for fresh consumption. When compared to many other fig cultivars, the local fruits are known to be very high in sugars, the most important criterion of quality in figs. The purpose of this study is to assess the impact of different agro-ecological zones on the fruit quality of local fig varieties. Besides, this work aims to identify the morphological characteristics of local fig varieties and estimate the quality of their fruit, respectively, according to the morpho-pomological traits based on the IPGRI and CIHEAM descriptors [10,11] and to the Aksoy's fig fruits quality descriptors [12], in order to conserve the fig germplasm and preserve this species from genetic erosion.

Materials sampling
The sampling region (made up of 7 provinces and a prefecture) located in the northeast of the country (fig1), it covers an area of 90.130 km², accounting for or 12.7% of the country's total land area [13].
Fig1. Geographical location of the study in eastern Morocco. The area is delimited, to the north by the Mediterranean Sea, and to the south by the arid region of Daraa-Tafilalete. The climate of this region is Mediterranean in the north, with rare precipitation, often in the form of strong thunderstorms and continental in the south, sensitive to Saharan factors, with cold in winter and heat in summer, low rainfall generally poorly distributed in time and space [13]. The identification of trees (Table 1) was made with the local vernacular name given by farmer to crop and cultivar, and they were selected for their widespread distribution and their commercial value in this region. Prospection and sampling were carried out on traditional orchards of farmers (adult trees of roughly the same age " ten years") at different locations in eastern Morocco (fig 1), in the early of February for the apical buds and during the period (June, July ,August and September) for the fruits and leaves. At the level of three different zones in each site, samples of 150 fresh fruits (ten fruits per plant and three plants per cultivars in each zone for two successive years 2019-2020) ripe and disease free were chosen, selected (the most basal on shoot) and harvested. According to the description instructions, the same sampling approach was used for leaves and apical buds.

Phenotypic and pomological Study
A digital scale was used to take the fruit weight measurements. ( were measured with a graduated ruler, while the thickness of the leaf stalk carried out with a digital caliper (in mm).As well as the terminal bud length and width were carried out with a digital caliper (in mm).

Chemical analysis
The chemical analyzes were carried out in triplicate and focused on the acidity and the Brix as a metric of fruit maturity parameters.

Statistical analysis
The data obtained was subjected to statistical analysis using IBM SPSS Statistics V21.0 software for descriptive statistics and also for analysis of variance by comparing average of characteristics studied using post hoc testing (Tukey's test) at the 5% threshold, graphs produced by the GraphPad Prism 8 software. The quality of the figs was assessed using the weighted ranked method by Aksoy [12], based on nine pomological characters.

Results and discussions
The morphological characterization of the figs was carried out on plant material available at the sampling site and therefore does not take into account the environmental component. Thus, the ease of peeling as well as the presence of skin cracks seems to be positive quality factors for figs intended for consumption in the fresh state.
On the other hand, the absence of cracks would be a positive parameter allowing better preservation of dried figs. In addition, we note that this type of figs without skin cracks is intended both for consumption in the fresh state as for the production of dried figs. According to this study, AH had the best quality in terms of peelability while MA had the best quality in terms of skin cracking ( The susceptibility for skin cracks is favored by low temperatures associated with high humidity during the fig ripening and especially common in genotypes with a thin epidermis [14]. Varieties that have a too long maturity are more vulnerable to the problem of skin cracks; they should not be grown in early and rainy autumn areas. When the fruits are ripening, fig cracking begins at the ostiole and is exacerbated by low temperatures and/or an increase in relative humidity [15]. The results show that fig weight (Fig 2) is high in AH (58. 09 ± 9.129 g) and CH (50.12 ±7.209 g) varieties and medium for GH (42.94 ±1.627 g) and BN (40.09 ± 2.182 g), while MA recorded the lowest weight (29.72 ± 1.767 g).The figs weight gives extremely attractive pricing for producers and traders in the market, for this purpose AH; CH and GH will certainly have the best chances of being appreciated by consumers. According to the results obtained concerning fig width (Fig 3), fig length (Fig 4)  The Shape fruit changes depending to the stage of maturity and cultural maintenance [16], or because of environmental conditions and genotypic effect [17].In the fresh fig sector, shape or index is particularly important. According to the findings of this study (Fig 5), the oblong form (I < 0.9) is represented in GH (0.694± 0.080) and AH (0.745 ± 0.049), whereas the globose shape (I = 0.9-1. Results have shown that AH (6.887 ± 1.10 mm) figs have the greatest ostiole width (Fig 10) followed by CH, GH, BN and MA (3.788 ± 0.24 mm) in that order. The largest pulp width (Fig 11) is seen in AH figs (43. 59 ± 3.528 mm), followed by CH, GH, BN, and MA figs (36. 84 ± 1.293 mm). A large ostiole will facilitate the entry and flight of blastophagous as well as pesticides and pathogens, which make varieties with this character unsuitable for the fig industry and storage [18]. The thickness of the internal pulp is a determining pomological character in the fruit quality and their use. This investigation has shown that the number of lobes per leaf (Fig 12) varies between 3 and 5 for AH (3.6 ± 0.9), MA (3.66± 0.94), CH (3.71 ± 0.96) and BN (4.2 ± 0.98) but for GH (5. 22 ± 1.38 mm) it is between 3 and 7. The great majority of the studied leaves have three lobes in AH, CH and MA in contrast to BN and GH they have five lobes.  The leaf stalks length is not proportional to the leaves length. When it comes to leaf stalk thickness, MA (4.912 ± 0.177 mm) is the thickest, followed by AH, GH, CH, and BN (4.043 ± 0.141mm) in that order (Fig18). We noticed that the leaf stalks length is not proportional to the leaf stalks thickness.
Concerning the leaf central lobe length (Fig 19), GH (11.13 ± 1.415 cm) is the longest then CH followed by AH; Morphological characteristics such as leaf size; number of leaves per shoot and pulp thickness; are important to selector and can be highly distinguishing variables. Nevertheless, differentiating fig tree varieties using their leaves is difficult because they are polymorphic within the same individual, particularly in terms of the number of lobes and the leaf stalk thickness [20].

Fig28.Figs total soluble solids average Fig29.Figs titratable acidity average
In order to determine the quality of figs; we use the weighted ranked method of Aksoy, based on nine characteristics which are with their weighting: the weight of the fruit (g) 20; beginning of maturation 20; shape of the fruit (index) 9; neck length (mm) 6; fruit skin cracks 10; ease of peeling 10; ostiole width (mm) 5; total soluble solids (%) 10 and titratable acidity (%) 10.The lowest score is obtained by MA (570),followed by BN (680) then GH (702), while the highest are recorded in particular at CH (720) and AH (738), theses scores reflect a very good pomological fig quality in the eastern Morocco (Fig 30). The fig quality is influenced by the genotypic effect, environmental conditions (temperature, humidity, wind...), the maturity stage and cultural maintenance [18].Certain pomological characteristics of apple, such as size and dry matter content, are more affected by the increase of the tree fruit load due to poor tree development. Thus, a weak tree development increases the effect of tree fruit load on fruit quality [24]. Moreover, from an agri-food standpoint, as a summer fruit, these fresh figs produced in this region have an excellent taste, they are sought after and appreciated by consumers, in particular the fruits of the cultivar AH, CH. Finally, the cultivars AH, GH deserve to be candidates for IGP labeling as fresh fruits, not only because of their outstanding quality, but also because of their good pomological parameters and high Aksoy weighted method scores.