Received 28 July 2016; accepted 26 August 2016; published 29 August 2016
Pearl millet has an ability to grow in environments of low and erratic rainfall, high temperature and low soil fertility  , so it has a wide geographic distribution and phenotypic diversity. It is a cereal fundamental for many people in semi-arid areas of Africa and Asia   . It was probably introduced during the eighth century in North Africa, where it is grown for seed production  . Millet [P. glaucum (L.) R. Br.] is a Poacea family, whose growing cycle varies from 48 to 120 days, characterized by a panicle that takes many forms. It is a sexual plant, diploid (2n = 2x = 14) by hermaphrodite flowers out crossing  with a female flowering earlier than flowering male and pollination by wind. This cereal avoids the drought that characterizes its culture area by closing stomata, lower leaf surfaces and the development of root system  .
The diversity of morphological traits was evaluated by many authors; for example, according to the length/ width ratio of seeds   or through other morphological characters it has strong heritability  . The domestication exchanges can be positive, allowing maintaining an important source of diversity among the cultivated form, or negative, for example diffusion with non-controlling genes transformed by genetic engineering  .
In South of Algeria (Sahara), especially Hoggar region, which is characterized by a typical desert climate, scalding and dry, the high temperatures of summer contrasted with those winters where it can freeze, rain is rare. However, these inhospitable conditions are less extreme than in the rest of the Sahara  . Despite these hard local climatic conditions, local millet maintained its original morphological diversity for centuries. They could accumulate significant genetic diversity between populations. Pearl millet [P. glaucum (L.)] is a cereal named as Dokhen (Arabic); the local name is Ineli (Targhi) or Bechna (Dialect). Originally, it’s from West Africa, particularly from the area of the north-east of the Senegal River. Its culture should produce seeds and fodder  . While in developed countries it is grown for forage, livestock and an ingredient in the animal feeds  .
This study aims to assess the biodiversity of pearl millet populations, whether cultivated or wild in this region (Hoggar), to use intensive selection criteria efficiently, and enrich our present knowledge about the local genetic resources of these cereals.
2. Material and Methods
2.1. Area Descriptions
The Hoggar covers an area of approximately 540,000 km2 (Quarter of the Algeria total area). It includes Tamanrasset town and the surroundings: Abalessa, In Amguel, Amsel and Tabrakat (Figure 1). It is an important crossroads of trade with the neighboring countries of the Sahel.
The region geomorphology distinguishes by Tidikelt plateau (in Salah region) in the North, covered with sand and the harsh climate. Hoggar (Ahaggar) South Mountain where temperatures are milder. The province is home to the highest peak in Algeria, Mount Tahat to 3003 m above sea level located in the Hoggar Mountains. It is located between the 12th and 25th parallel of the northern hemisphere, straddling the Tropic Cancer, and the 3rd and 6th meridian east of Greenwich. The Hoggar consists mainly of volcanic rocks, desert of rocks, erosion has shaped a stunning landscape while sharp peaks, due to a less extreme than the rest of the Sahara, and it is an important refuge for some plant and animal species. On the ecological point of view, it can be differentiated from the rest of the Sahara, generally, the soils encountered in this region reveal somewhat or very advanced, following insufficient moisture, these soils are zonal crude  , with profiles poorly differentiated or non-exis- tent  .
Generally, precipitation occurs in May to September, following the rise of Sahara intertropical front and the extreme south of Algeria. In his general conclusions about the main characters rainy Saharan, Dubief (1959)  reported that, they are rare and generally low quantitative importance. However, the Hoggar climate, type “little tropical Mediterranean”, is more desert by low rainfall, that by their rarity. As for the thermal regime, it is very mixed, influenced by altitude and latitude. On average the month of June is the hottest of the year with 40˚C in Tamanrasset, 1395 m altitude and 28˚C in Assekrem to 2728 m, and January the coldest month, with temperatures approaching absolute every low temperatures (−13.5˚C in 1993)  .
The study of the flora and vegetation shows the existence of specific Sahara species (Artemisia, Tamarix, Ficus, Panicum, Palm, Ziziphus...)   , which are added Mediterranean elements (Olive, Myrtle, Lavender...) and tropical (Acacias, Calotropis, Balanites...)  ,  . However, the uniqueness of this plant is its poverty indisputable because of extreme weather conditions. Also, due to its high elevation, the Hoggar is less warmer
and less arid than desert plain, served refuge for plants that are excluded from it, including relics to Mediterranean or Tropical strains that once these reached massive thanks to the wetter periods. It shows a high level of endemism, which increases with altitude  .
The followed way for millet groups identification, is from the North- east of Tamanrasset (In Amguel, 130 Km) to Abalessa (100 km) Nord-west of the region, as traditional old fields. We were passed through intermediate sites, Amsel (20 km) South-west of Tamanrasset town and Tabrakat (4 km) Est, as new and modern fields, where the farmers apply modern irrigation systems. A total distance of 255 km. seven groups of traditional and new fields finding in that way were inspected in November 2008, 2010 and October 2011 during panicles maturation period of plant, data location of sites visited are recorded (Table 1).
2.2. Experimental Material
The experimental material is composed of 09 millet accessions, cultivated in different sites of Hoggar region. There are two types of fields, Traditional in Abelessa; very old soil with a traditional irrigation system, (Traditional wells). Besides, there are new fields (Amessel, In Amguel and Tabrakat) where the farmers use generally, a modern irrigation (Drip system) and there is a new rich soil too. Therefore, morphological characterization was only carried out for those accessions that performed well under field condition during cropping season (Table 2).
2.3.1. Morphological Study
Data were collected by search members and a supervisor with the help of local farmers. Descriptive study; qualitative characters and quantitative measures of millet morphological parameters, were realized at plant maturation stage in the different fields of sites according to Andrews and Kumar (1992)  of millet descriptors, for example: Plant Height (PH), Number of Nodes (NN) and Leaves (LN), the third leaf dimensions; Length (LL) Width (LW) and Panicles Colors (PC) at maturation (Table 3), the color being determined based on Royal Horticultural Society (RHS) color codes  .
Table 1. Sites visited in Hoggar region during cropping season (November 2008, 2010 and October 2011).
Table 2. Local appellations of millet accessions with their collection sites in Hoggar region.
Table 3. Quantitative characters recorded in the study sites along with their codes and descriptions.
2.3.2. Cytological Study
The characterization study and evaluation of millet panicles and seeds collected from different sites were conducted in order to use a descriptive and cytological study based on the parameters of The International Board for Plant Genetic resources (IBPGR) and ICRISAT descriptors  . Concerning Panicle Form (PF), Panicle Setae (PS), type of Seed Envelop (SE) and Seed Form (SF) (Table 4). Endosperm texture was defined as the proportion of corneous relative to floury endosperm in the grain, which was determined subjectively by viewing sectioned kernels using a stereomicroscope, and comparing them to sorghum standards  . The kernels were classified as corneous, intermediate or floury  . The moisture analysis content was carried out according to AACC methods 44-15A  . For the main millet groups (local and domesticated) where realized in laboratory.
2.3.3. Statistical Analysis
The qualitative and quantitative data of accessions millet were organized by four repetitions and analyzed by Analysis of Variance (ANOVA). Differences in mean values were assessed at the 0.05 probability level using least significant difference (LSD) method. SPSS. Statistics version 17.0 Logical.
3. Results and Discussion
3.1. Morphological Parameters
In fact, development and yield of pearl millet were markedly affected by temperature during plant growth: vegetative, stem elongation, and grain development  . High morphological variation was recorded among the 9 accessions of pearl millet [P. glaucum (L.)] from different sites study of Hoggar region, Despite the availability of the same field conditions, The most variations were observed in the height plant (HP) of the introduced millet, from 1.74 to 1.79 m (MHD.S and MHD.S epL) compared with local millet (1.12 - 1.64 m) (Table 5). Many researchers found that height plant generally, decreased with delayed planting  .
Table 4. Qualitative characters recorded in the study site.
Table 5. Pearl millet quantitative characters of Hoggar region during cropping season (mean ± standard deviation, n = 4).
In addition, environmental conditions affected panicle size on the main stem and yield on tillers in the same sense  . Found that panicle length was maximized between 5 and 17 May. So, panicles colors (PC), panicle length (PL). These are the qualitative characters and they can help in clear cut identification of particular genotype  . Number of leaves (NL) and stem diameter (SD), were observed to be positive and highly significant between two groups; local and domesticated millet. Whereas very low variation was noted in third leave dimensions (LL and WL), and Panicle Wide (PW), where no significant difference was observed between local and domesticated millet. We present the main millet groups for Hoggar region based on the panicle form, color and dimensions (Figure 2 and Table 6).
3.2. Cytological Parameters
The standard millet descriptors of IBPGR and ICRISAT (1993), was used as a guide to take data, concerning the determination of Seed Number in Spikelet (SNS), position of Seed Envelop (SE), Seedcolors (SC) (Table 7). The cytological results of seeds show that, millet groups that have a high proportion of Corneous or Starchy endosperm (Figure 3 and Figure 4) are the preferred groups and have a high panicle nutritional value (MLH.Z1, MLH.S and MDH. Saf), Unlike those of millet groups that have an intermediate endosperm proportion (MLH.N, MDH. Saf.P, MLD.Z2 and MDH. SepL) (Table 8).
1-MLH.epc 2-MLH.Saf 3-MLH.N 4-MLH.Z1 5-MLH.Z26-MDH.Saf.P 7-MDH.Saf 8-MDH.SepL 9-MDH.S
Figure 2. Different types of pearl millet panicles in plant maturation stage for Hoggar region.
Figure 3. Local millet (MLH.epc). (a) Spikelet and seed; (b) Cross (CS) and longitudinal section (LS) in the seed.
Figure 4. Domesticated millet (MDH.S). (a) Spikelet and seed; (b) CS and LS in the seed.
Table 6. Panicle characters of pearl millet groups in Hoggar region during the cropping season.
+: Existence of PS, ++: Existence of long PS, −: Absence of PS.
Table 7. Seeds characters of pearl millet groups in Hoggar region during the cropping season.
Table 8. Endosperm texture of Pearl millet seeds for Hoggar region.
According to the investigation made about the morphological and cytological parameters of millet groups in the different studied sites on November 2008, 2010 and October 2011 in plant maturation stage, and the discussions with farmers interested for this kind of cereal culture, in addition to the observations on plant height, number of nodes, spike length and bristle length were recorded and the data were pooled over the locations; these could be grouped into distinct classes and could be useful for varietal identification and genetic purity testing. Based on standard descriptors, we distinguish generally, three main groups of pearl millet in this region  -  .
4.1. Local Millet Group
Enélé ouan Ahaggar: Local pearl millet from Hoggar region, characterized by short height and very short blue panicle (MLH.Z1, MLH.Z2) Zerga (Bleu) and medium height with yellow panicle (Saffra) (MLH.saf) and millet with short panicle (MLH.epc).
4.2. Domesticated Millet Group (1)
A-Enélé ouan Tidikelt: Local pearl millet from Tidikelt (Touat) region, characterized by short to medium stems (1.45 - 1.75 m) with yellow panicles (MDH. Saf) sometimes hairy panicles (safra lamchaara (MDH. Saf. P).
B-Enélé ouan Djanét: Local pearl millet from Janet region has the same characters with the Tidikelt region millet.
4.3. Domesticated Millet Group (2)
This group locally named from their origin source, so we distinguish five principal subgroups:
A-Ineli Ouan Targa: Pearl millet introduced from Targa region, capital of Oubali in Libya, where habitant the Zintanes family in Targa valley this group of millet characterized by short (5 - 10 cm) and precocious panicles, with abundant Setae, and high nutritive value, blue gains, with legs texture of stems and leaves so, it’s a good fodder for animals.
B-Ineli Ouan Agadés: Pearl millet introduced from Agade’s region (Niger) this group of millet characterized by a long stem (2 - 2.35 m), long panicles too, (40 - 55 cm) grey-yellow color with abundant Setae (MDH.S).
C-Ineli Ouan Taboutqut: Pearl millet introduced from Taboutqut region (Niger), characterized by medium height plant and panicle too.
D-Ineli Ouan Damergou: Intrduced from Damergou region (Niger) this group of millet characterized by tardy panicles maturation, longue panicles (60 - 100 cm) longue (MDH. SepL), yellow grains, their rough stems and long leaves too.
E-Ineli Ouan Tahoua: Introduced from Tahoua region (Niger), this millet characterized by long panicles (40 - 65 cm), tardy maturation and yellow-light red grains, with rough stems and long leaves too, but less than Damergou group.
Following the codes provided by RHS, the Hoggar accessions exhibited five main panicle colors of, yellow, grey, deep-grey, green and black during the evaluation.
These results show that it is possible to select and improve forms (cultivars) according to local needs, based on morphological and cytological data of the plant, panicles and especially the structural characteristics of the seed. Despite its potential agronomic, especially drought tolerance and nutritional quality, millet continues to be marginalized in Algeria; this assessment is certainly a great contribution to enhancing the value of this cereal adapted in arid areas of Algeria. This study is assumed to identify the potential impact of local consumption in this region.
We are grateful to Hoggar local farmers. Especially, Nadjemi Hadj Med. and Hadji A. Familly. The members assembly municipal of In Amguel and Abalessa; Mr. Dahkhal, Mr. Ba Mhamed, for their help.
Analysis of Variance (ANOVA)
Take into account the Sig. < 0.05.
Dendrogram using Ward Method
Rescaled Distance Cluster Combine
HIERARCHICAL CLUSTER ANALYSIS
Total Variance Explained
Extraction Method: Principal Component Analysis.
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