Pearl millet

3.1 Material and methods Pearl millet line LCICMB 1 was used in this experiment. The seeds were surface- sterilized by a 2 minute immersion in 10% hypochlorous acid followed by 2 minutes in 70% ethanol. Each bath was followed by 3 rinses in deionised water. Then the seeds were germinated in Petri dishes at 30°C in the dark for 24 hours. Germinated seedlings were transferred to pots (50 mm diameter and 120 mm height) containing “Newport Series Loamy Sand” soil (sand 83.2%, silt 4.7%, and clay 12.1%; organic matter 2.93%; pH = 7.13; Nitrate = 5.48 mg.L -1 ; Phosphorus = Defra index of 3 (29.65 mg kg -1 )) one DAG. Half of the soil was inoculated with spores of Rhizophagus irregularis. Spores originated from 3 Petri dishes containing transformed carrot roots, cultivated on phytagel at room temperature (20°C) until the hyphae covered all the dishes. Presence of spores was assessed using a stereomicroscope and phytagel was dissolved in sodium citrate solution (10 mM, pH = 6) at 35°C to retrieve hyphae bearing the spores. Retrieved fungus material was rinsed with sterile watered and stored until inoculation. This was done by mixing the spores with 4.5 kg of soil. Half of the plants were maintained throughout the experiment at a soil water content of ~26% (w:w), which corresponds to 75% of field capacity. The other half was maintained at a SWC of ~9% (w:w) corresponding to 25% of field capacity. Overall, 4 treatments were tested on 6 plants each: well-watered without inoculation, well-watered with inoculation, drought-stressed without inoculation and drought-stressed with inoculation The SWC was monitored daily by weighing the pots. Plants were scanned with a v|tome|x M scanner (Phoenix/GE Systems), with a maximum energy of 240 kV, 4 times over a 18 days period (4, 8, 14 and 18 DAG) to image the root structure. Two days after the last scan, the aerial parts of the plants were collected, oven dried during 72 hours and weighted. The root system of each plant was washed and fixed at 95°C in a 10% KOH solution. The roots were then rinsed with water and stored in a 10% acetic acid solution. They were dyed 3 minutes at 90°C in a staining solution containing 5% Schaffer ink and 5% acetic acid to stain mycorrhizal (fungal) structures (Vierheilig et al., 1998). The roots were rinsed with water and stored at 4°C in Petri dishes before observation. The observations were made with a stereomicroscope (Zeiss).

Simple sequence repeat (SSR) molecular markers were used for genetic diversity analysis and population structure of the cultivated Pearl millet in Benin, West Africa. In order to assess the level of genetic diversity, 14 polymorphic SSR markers were used to screen 114 accessions from different agro- ecological zones in Benin. SSR markers were found to reveal a total of 57 alleles with an average of 4.071 allele per locus. Genetic diversity index varied from 0.099 to 0.633 with an average of 0.405. The average observed heterozygosity was found to reach 0.425. The analysis of molecular variance showed no real differentiation between regions. Only 5% of genetic variation was observed between samples collected from north-eastern and north-western region. A high level of variation (95%) was observed among accessions. Moreover, both principal component analysis (PCA) and the dendrogram obtained from the genetic distance among accessions revealed the absence of any specific structuration of accessions from each region under study. Our results confirmed diversity among cultivated Pearl millet in Benin and such diversity is not clustering according to geographical patterns.

Senegal Pearl millet (Pennisetum glaucum (L.) R. Br.) is a staple food and a drought-tolerant cereal well adapted to Sub-Saharan Africa agro-ecosystems. An important diversity of pearl millet landraces has been widely conserved by farmers and therefore could help copping with climate changes and contribute to future food security. Hence, characterizing its genetic diversity and population structure can contribute to better assist breeding programs for a sustainable agricultural productivity enhancement. Toward this goal, a comprehensive panel of 404 accessions were used that correspond to 12 improved varieties, 306 early flowering and 86 late-flowering cultivated landraces from Senegal. Twelve highly polymorphic SSR markers were used to study diversity and population structure. Two genes, PgMADS11 and PgPHYC, were genotyped to assess their association to flowering phenotypic difference in landraces. Results indicate a large diversity and untapped potential of Senegalese pearl millet germplasm as well as a genetic differentiation between early- and late-flowering landraces. Further, a fine-scale genetic difference of PgPHYC and PgMADS11 (SNP and indel, respectively) and co-variation of their alleles with flowering time were found among landraces. These findings highlight new genetic insights of pearl millet useful to define heterotic populations for breeding, genomic association panel, or crosses for trait-specific mapping.

* laurent.laplaze@ird.fr (LL); yves.vigouroux@ird.fr (YV) Abstract Pearl millet plays a major role in food security in arid and semi-arid areas of Africa and India. However, it lags behind the other cereal crops in terms of genetic improvement. The recent sequencing of its genome opens the way to the use of modern genomic tools for breeding. Our study aimed at identifying genetic components involved in early drought stress toler- ance as a first step toward the development of improved pearl millet varieties or hybrids. A panel of 188 inbred lines from West Africa was phenotyped under early drought stress and well-irrigated conditions. We found a strong impact of drought stress on yield components. This impact was variable between inbred lines. We then performed an association analysis with a total of 392,493 SNPs identified using Genotyping-by-Sequencing (GBS). Correcting for genetic relatedness, genome wide association study identified QTLs for biomass produc- tion in early drought stress conditions and for stay-green trait. In particular, genes involved in the sirohaem and wax biosynthesis pathways were found to co-locate with two of these QTLs. Our results might contribute to breed pearl millet lines with improved yield under drought stress.

Pearl millet [ Pennisetum glaucum (L) R Br.] is a key cereal for food security in arid and semi-arid regions [ 41 ]. However, its yields are low and are often affected by climate unpredict- ability (heat waves and dry spells), which is forecast to worsen [ 42 , 43 ]. The recent release of the pearl millet genome has opened new opportunities for functional genomic-based efforts to improve pearl millet yield and abiotic stress tolerance [ 44 ]. In this study, links between AQP function in roots and water use were investigated by measuring AQP contribution to Lpr in two pearl millet inbred lines contrasting for water use efficiency. The entire AQP family in pearl millet was characterized using a genomic approach and analyses of root AQP gene expression provided insights into how AQP isoform contribute to root hydraulics.

Abstract  Ben‐kida and ben‐saalga are popular pearl‐millet‐based fermented gruels in Burkina Faso. A  survey of 318 households in Ouagadougou (Burkina Faso) showed that they are often used as  complementary food for young children. Pearl millet and gruels, sampled in 48 production  units  were  analysed  for  proximate  composition,  factors  reducing  nutrient  bioavailability  (phytate, insoluble fibres and iron‐binding phenolic compounds), alpha‐galactosides, sugars,  total lactic acid and D‐lactic acid, zinc and iron contents. The effects of processing of pearl  millet  into  fermented  gruel  are  discussed.  Both  positive  effects,  e.g.  a  decrease  in  factors  reducing  nutrient  bioavailability  or  alpha‐galactosides,  and  undesirable  effects,  e.g.  considerable  lipid,  protein,  iron  and  zinc  losses  were  observed.  Lactic  acid  was  produced  during processing and D(‐)lactate was detected in all samples. 

338 340 342 In our cultivation conditions, senescence did not appear to be a specific response to intermediate water deficits. Payne et al. (1991) concluded the same in a growth analysis study of pearl millet. On the control plants, senescence was already severe at 60 DAE, in conjunction with the reduction of irrigation. The same phenomenon appears in nature where the length of the dry periods in the region of Tanout increases considerably from the 50th day after sowing (Sivakumar, 1991). The leaf senescence which affected essentially the tillers accompanied the important loss of their stem biomass and coincided with the rapid growth of the panicles of the main shoots on the control plants.

Drought is one of the main factors limiting pearl millet yield and drought episodes are pre- dicted to increase in number and length in the future in West Africa [ 7 , 32 ]. Previous studies suggested that pearl millet tolerance to dry environments could be due to mechanisms regulat- ing water use efficiency and limiting water loss rather than to improved water acquisition [ 33 ]. Interestingly, an expansion of gene families involved in cutin, suberin and wax biosynthesis was observed in pearl millet compared to other cereals and a potential QTL for biomass pro- duction under drought was found to co-locate with a gene encoding 3-ketoacyl-CoA synthase that catalyzes the elongation of C24 fatty acids during both wax and suberin biosynthesis [ 17 ] thus supporting the link between transpiration barriers and drought resistance in pearl millet. Experiments using lysimeters indicated that temporal patterns of water use, rather than total water uptake, were essential for explaining the terminal drought tolerance of pearl millet geno- types containing a terminal drought tolerance QTL [ 34 ]. Therefore, this terminal drought

2014 ; Manning and Fuller 2014 ). In the case of the Acacus region of Libya, however, Pennisetum sp. drops out of use by ca. 6200 BC, with subsequent plant exploitation and probable cultivation focusing on small millets, such as Panicum and Echinochloa (Mercuri et al. 2018 ). Indeed, Winchell et al. ( 2018 ) suggest three distinct, yet parallel, pathways to cereal cultivation in Africa that were each initially based on different grasses: small millet cultivation in the central Sahara, sorghum in the eastern Sahel, and pearl millet in the western Sahel. Wild pearl millet was plausibly a grain staple millennia before the earliest evidence of its domestica- tion in the later third millennium BC. From this time onward, morphological changes that are characteristic of the domestication process are documented at many

Confirmation of Variation in RAS/RT Ratio To continue our study with a smaller number of pearl millet lines, we selected firstly 16 contrasted lines among the 86 lines screened in the previous experiment. These lines were selected from the blocks where statistically significant effects were found, and chosen as exhibiting average RAS/RT values close to the lowest or highest value observed within the block. Other parameters of choice were: availability of germplasm, phenological homogeneity, germination success. We conducted a second phenotyping experiment on these 16 lines in a single batch. We observed significant difference of the ratio RAS/RT between lines and a global coherence in phenotype between this batch and previous experiment. For instance, L8, L82, and L44 which were selected from the lines expressing relatively low RAS/RT ratios in blocks during the whole set phenotyping, also had lower RAS/RT ratio compared to the others lines in this batch (Figure 1H). For the third experiment (same conditions than during screening, but now 10 repeats per line in order to enhance strength of the ANOVA analysis) we selected 9 lines from the 16, taking two groups which appeared statistically separated in the 16-lines experiments, i.e., L8, L44, and L82 with low RAS/RT values, vs. L12, L14, L39, L57, L92, and L118 with high RAS/RT values. The separation between these groups appeared consistent in this third experiment (Figure 2). Again the ratio RAS/RT was not correlated with soil moisture (Table 1). The RAS was positively correlated with root and shoot biomass: plants with larger root development mechanically carry more root-adhering soil. On the other hand, RAS/RT ratio was negatively correlated with shoot biomass, which might be in line with an increased C sink in root exudation. When pooled together, the two groups of lines “low RAS/RT ratio” (L8, L82, and L44) and “high RAS/RT ratio” (L92, L12, L118, L14, L57, and L39) were clearly separated in terms of average RAS/RT ratio, the difference being highly significant (respectively 9.15 < 19.35 g/g; Student t-test p < 0.0001).

IDT3-012 | Impact of three lateral root types identified in pearl millet on water uptake Passot S. 1 *, Meunier F. 1 , Muller B. 2 , Javaux M. 1 , Draye X. 1 , Guédon Y. 3 , Laplaze L. 4,5 1 Earth and Life Institute - Agronomy, UCL, Louvain-la-Neuve, Belgium 2 LEPSE, INRA, Montpellier, France

Timbo De Oliveira et al. (2010). Unlike other grasses or cereals such as rice, where the experiments were reproducible, work on Pennisetum has not yet led to reproducible regeneration from protoplasts (Mtili, 1990). Except for the use of isolated protoplasts for the expression of foreign genes (Tiécoura et al., 2001), studies on protoplasts of pearl millet, Pennisetum glaucum, varieties of Côte d'Ivoire are scarce. In this work, we present protoplast culture assays of pearl millet, Pennisetum glaucum, varieties of Côte d'Ivoire, the conditions of isolation, culture and plant regeneration from protoplasts.

 provides anemia thanks to its high grain iron contents (60-65 ppm iron).  more easily digestible than the ones found in wheat 3. Pearl millet Biodiversity Pearl millet were cultivated in In Salah and Tamanrasset (Sahara of Algeria) known to have high temperatures (11-47°C) and low rainfall rate (2-29 mm/year).

Despite its importance, pearl millet is considered as an orphan crop because it has received very little support from science, industry and politics while other crops such as wheat, rice, or maize were subjected to intense efforts of genetic and agronomic improvement. As a result, it lags behind sorghum and far behind the other major cereals in its genetic improvement. Its average grain yields barely reach 900 kg/ha, compared to 1500 kg/ha for sorghum ( Food and Agriculture Organization of the United Nation [FAO], 2014 ). Moreover, production has increased by only 0.7% a year in West Africa during the last two decades, the lowest growth rate of any food crop in the region and far less than the population’s growth rate of nearly 3% per year ( United Nations Statistics Division, 2016 ). However, its untapped genetic potential is vast and could be used to improve pearl millet tolerance to some environmental factors that are the main limitations to its growth potential. For instance, pearl millet is mostly grown in marginal soils such as sandy soils in Western Sahel where low water and nutrient (particularly phosphate) availability are major limiting factors. Moreover, root establishment in poor soil is essential to ensure efficient use of available water.

Genetic diversity within and among early and late landraces at neutral loci. This study revealed that the early and late landraces did not show significant genetic differentiation at the STS loci. The same level of genetic diversity was observed in both the early and the late landraces. These results could challenge the hypothesis of Tostain et al. [14] according to which the late landraces have evolved from a secondary diversification of early landraces at the west of the actual Lake Chad region. Other hypotheses on the origin of late landraces can be proposed. For example, they could have been the result of several independent local selection processes from early landraces all along the geographic distribution area of pearl millet. Yet, to our opinion, no strong arguments can actually be put forward against the fact that late landraces could have preceded early landraces. Indeed wild pearl millets are early flowering plants but nonetheless strongly sensitive to photoperiod as most wild plants in tropical areas. This characteristic ensures the coincidence between the rainy season and the life cycle of wild plants. Early landraces of pearl millet are also early flowering but much less photosensitive while late landraces have been shown to be late flowering and highly sensitive to day length [8,10]. It is therefore difficult to single out a hypothesis about the evolutionary trajectories of both the cycle duration and the sensitivity to photoperiod, which have occurred within the cultivated gene pool since the beginning of pearl millet domestication.

Furthermore, crop adaptation to agricultural practices and local conditions, through farmers’ seed selection, is also involved in crop diversity patterns (Mercer et al., 2008; Pressoir & Berthaud, 2004b). The combination of seed selection and diffusion processes was nota- bly involved in diversity patterns of barley in Ethiopia and rice in Yunnan, where particular landraces were circumscribed to specific ele- vations (Samberg et al., 2013; Xiong et al., 2010). Similar results were also reported for maize in Mexico where genetic differentiation among elevation zones was observed at a regional scale (van Heerwaarden, 2007), while other studies found that ethnolinguistic differences have a stronger impact than elevation at a local scale (Orozco- Ramírez et al., 2016). For sorghum, most studies reported a very weak relationship between neutral genetic diversity patterns and elevation or agro- climatic zones at a country scale (Ayana, Bryngelsson, & Bekele, 2001; Deu et al., 2008; Mutegi et al., 2011). For pearl millet, this topic is still understudied, but recent studies found a relationship between allelic frequencies at a gene associated with flowering time and annual rain- fall variations in Niger (Mariac et al., 2011).

The replanting (5-10%) of missing hills in the on-farm trial increased stand variance significantly, whereas small quantities of applied N reduced it. Grain yield and grain numb[r]

The reasons for the spread of pearl millet (n=538). Circles are proportional to the spread percentages of exchanges Our results provide a better understanding of farmer seed networks. This study highlights a gap between agricultural policies and local seed management by farmers, results that could feed into the reflection on the governance of plant genetic resources.

1. Introduction Pearl millet is one the most important food crop in Mali and tropical. Millet diseases are important items in the reduction of quality and quantity in crop millet. Therefore, the detection and diagnosis of these diseases are very necessary. Traditional techniques of identification diseases require experts' knowledge of agricultural areas. Use these approaches to improve detection disease are difficult and less efficiently. However, the computer vision and the Internet of Things offer a new way disease crop detection based automatic pattern recognition. In fact, they contribute together about the development of agriculture. Thus we need to develop tools and methods to analyze, interpret and visualize the data in order to achieve significant results ( e.g. meaningful outcomes in the detection of patterns in images). These systems will permit to generate knowledge support to help the farmers in the decision making process through execution of decision support systems (1 ).

INTRODUCTION The world population has been growing significantly since the end of World War II while giving birth to an imbalance between demographic evolution and food self-sufficiency in many regions through the world (Rosenzweig & Parry, 1994) But it becomes more and more difficult to increase that agricultural production due to climate changes that can cause drought, floods and the emergence of new pests jeopardizing the most vulnerable species or plant varieties. In Africa, especially in the Sahel region, food security is mainly based on cereal and some farming activities for private income; among them production of millet, which occupies a very important place (Saidou et al., 2009). Millet, Pennisetum spp, is the most tolerant cereal to drought. Its cultivation covered more than 30 million hectares in 1994, and was distributed mainly in arid and semi arid areas of Africa. Millet, being the staple of the people, is squarely the most important cereal in Senegal for both the planted area and for the production (MAE, 2001). Millet represents on average more than 60% of cereal production in Senegal (about one million tons / year) mainly from the groundnut bassin and Tambacounda. Pearl millet (scientific name) is the type almost exclusively used in Senegal as human food and/or animal feed (Diakhaté, 2013). Farming average yields varies between 0.5 and 0.6 t / ha. These low yields that vary between 0.5 and 0.6 t / ha, result from a combination of abiotic constraints: