Acta agriculturae Slovenica, 118/1, 1–15, Ljubljana 2022 doi:10.14720/aas.2022.118.1.1972 Original research article / izvirni znanstveni članek Performance and genetic diversity of some sesame (Sesamum indicum L.) accessions based on morpho-agronomic traits and seed proximate com- position in Kwara State of Nigeria David Adedayo ANIMASAUN 1, 2, Stephen OYEDEJI 1, Latifat Bukola MUSA 1, Peter Adeolu ADEDIBU 1, Olabisi Fatimo ADEKOLA 3 Received November 25, 2020; accepted February 07, 2022. Delo je prispelo 25. novembra 2020, sprejeto 7. februarja 2022 1 Department of Plant Biology, Faculty of Life Sciences, University of Ilorin, Ilorin, Nigeria 2 Corresponding author, e-mail: animasaun.ad@unilorin.edu.ng 3 Department of Agronomy, Faculty of Agriculture, University of Ilorin, Ilorin, Nigeria Performance and genetic diversity of some sesame (Sesamum indicum L.) accessions based on morpho-agronomic traits and seed proximate composition in Kwara State of Nigeria Abstract: This study evaluates eleven sesame accessions in Nigeria for performance and genetic diversity using morpho- agronomic traits, chlorophyll contents and nutrient composi- tion in a complete randomized experimental design with five replicates. The results showed ‘Igboho Black’, ‘02M’ and ‘Ke- nan 4’ had the best growth attributes. Although ‘NGB0090’ and ‘Exsudan’ matured early, ‘E8’, ‘Bogoro Local’ and ‘Kenan 4’ had the best yield attributes. Seeds produced were predomi- nantly milky-white, an accession had black seeds, while three produced white seeds. Plant height positively correlated with number of leaves and leaf area as well as peduncle length. Days to 50 % flowering positively correlates with days to maturity. So also the number of capsule per plant, capsule dimension and seeds per capsule. The moisture content in seeds of the acces- sions was < 3.5 %, ash (4.5-5.9 %), crude protein (5.3-7.4 %), fat and oil (53.6-60.5 %), and carbohydrate < 30 %. Out of the eight components that accounted for the observed variations, the PC-1 and PC-2 contributed 65.42 %. The dendrogram re- vealed that ‘NGB00960’ and ‘NGB00963’ which had ‘’Kenan 4’ as a distant member are the closest relatives, while ‘NGB00390’ and ‘01M’ are the most diverse. The study concludes that the accessions are genetically and phenotypically varied and the ex- isting diversity can be harnessed for selecting high yielding and adaptable variety for the development of improved cultivars. Key words: chlorophyll content; genetic diversity; mor- phometric attributes; oilseed Preučevanje uspevanja in genetske raznolikosti nekaterih akcesij sezama (Sesamum indicum L.) na osnovi morfoloških in agronomskih lastnosti ter zgradbe semen v državi Kwara, Nigerija Izvleček: V raziskavi je bilo ovrednoteno sedem akcesij sezama iz Nigerije glede na uspevanje in genetsko raznolikost z uporabo morfološko-agronomskih lastnosti, vsebnosti klo- rofila in hranil v popolnem naključnem bločnem poskusu s petimi ponovitvami. Rezultati so pokazali da so imele akcesije ‘Igboho Black’, ‘02M’ in ‘Kenan 4’ najboljše lastnosti. Čeprav sta ‘NGB0090’ in ‘Exsudan’ dozorevali zgodaj, so imele ‘E8’, ‘Bogoro Local’ in ‘Kenan 4’ najboljše lastnosti pridelka. Seme- na so bila pretežno mlečno bela, ena akcesija je imela črna se- mena, tri pa popolnoma bela. Višina rastlin je bila v pozitivni korelaciji s številom listov kot tudi z dolžino cvetnih pecljev. Dnevi potrebni do 50 % cvetenja so bili v pozitivni povezavi z dnevi do zrelosti. V podobni povezavi je bilo tudi število plo- dov na rastlino, dimenzija glavic in število semen na glavico. Vsebnost vlage v semenih je bila večja od 3,5 %, vsebnost pe- pela 4,5-5,9 %, celokupnih beljakovin 5,3-7,4 %, maščob in olj 53,6-60,5  % in ogljikovih hidratgov več kot 30  %. Od osmih komponent, ki so pripspevale k ugotovljeni raznolikosti sta komponenti PC-1 in PC-2 pripevali 65,42 %. Dendrogram je pokazal, da so ‘NGB00960’ in ‘NGB00963’, ki vključujeta od- daljeno akcesijo ‘Kenan 4’ najožji sorodniki, med tem, ko sta ‘NGB00390’ in ‘01M’ najbolj raznoliki. Na osnovi raziskave je bilo ugotovljeno, da so akcesije genetsko in fenotipsko različne in da bi se njihova raznolikost lahko izkoristila za izbor visoko donosnih in prilagodljivih različic pri razvoju izboljšanih sort. Ključne besede: vsebnost klorofila; genetska raznolikost; morfometrične lastnosti; vsebnost olja v semenih Acta agriculturae Slovenica, 118/1 – 20222 D. A. ANIMASAUN et al. 1 INTRODUCTION Sesame (Sesamum indicum L.) also known as ‘ben- niseed’ is an important member of the Pedaliaceae fam- ily. It is an ancient tropical crop of high economic impor- tance, widely known for its seed edible oil. The origin of the cultivated sesame is controversial. There are claims that it originated in the Savannah of tropical Africa and was introduced into India and China by early humans (Purseglove, 1977; Naturland, 2002; Bedigian, 2004; Be- hera et al., 2017). There is also a concept of Indo-Asian centre of origin and diversity of sesame. While the pres- ence of wild types and abundance supports Africa as the centre of origin (Ram et al., 1990), interspecific crosses and lignan analyses refuted the same (Bedigian et al., 1985; Bedigian & Harlan, 1986) and pointed at Indo-Asia origin of progenitor sesame. The world sesame production is approximately 5.5 million metric tonnes, of which 70  % are produced in Asia while Africa accounted for about 26 %. African ma- jor producers include Ethiopia, Sudan, Uganda and Ni- geria (FAOSTAT, 2011; Pathak et al., 2014). India ranks top in global sesame production followed by China (An- thony et al., 2015). However, the average yield per hec- tare is highest in China, followed by India, and Tanzania. Meanwhile, China is the world’s largest consumer of ses- ame (FAOSTAT, 2020). Despite the peachy production of sesame in Nigeria, productivity is comparatively low. There is a need to accelerate its production through the use of improved genotypes and farming practices. Sesame is a herbaceous annual plant that can grow up to 1.5 m in height. The fruit has many seeds enclosed in a capsule. The seeds are small, oval, and almost oblate in shape. They vary from cream-white to charcoal-black but often white or black and may also be, yellow, red or brown depending on the variety (Naturland, 2002; Ben- net, 2011). Although sesame is adapted to various ecolog- ical conditions, it thrives better on well-drained, fertile soils. The temperature requirement is between 20-35 ◦C (Misganaw et al., 2015). Most varieties are drought and insect resistant with negligible economic loss from pests (Langham et al., 2008). The seed oil is rich in sesamol which is an important anti-oxidant, and polyunsaturated fatty acid that is safe for human and animal consumption (Ashri, 1998). Also, the oil is used majorly for cooking, for making margarine, soap, paints, lubricants and lamp fuel. The seeds are equally nutritious, containing protein (18–25  %), carbohydrate (about 13  %), calcium, phos- phorus, iron, essential minerals and vitamins (Bedigian et al., 1985; Bedigian, 2004). Sesame seed contains more oil than major oilseed crops such as peanut and soybean (Ashri, 1998). However, seed oil quantity and quality may vary, depending on the genotype and growth condi- tions (Myint et al., 2020). The medicinal usage of sesame oil as an anti-oxidant, anti-tumour, anti-cholesterol and anti-microbial agent have been reported (Sankar et al., 2005; Costa et al., 2007). Sesame improvement to meet the growing demand for seed oil requires adequate knowledge of the genetic diversity and relationship among the available germ- plasm. The genetic diversity among sesame accessions and genotypes based on morphological parameters has been established from different studies conducted over the years (Bisht et al., 1998; Baydar, 2005; Arriel et al., 2007; Furat & Uzun, 2010; Parameshwarappa et al., 2010; Frary et al., 2015; Kiranmayi et al., 2016; Azeez et al., 2017; Iqbal et al., 2018). The authors reported significant variations among the genotypes studied and elucidated the genetic relationship among the accessions. Further- more, more recently, Adu-Gyamfi et al. (2019) employed morphological traits in the assessment of the diversity of selected sesame genotypes cultivated in Northern Ghana. However, Nigerian accessions of sesame have not been well characterised, more so, the number of available ac- cessions cannot be accurately ascertained. So there is a need to characterise as many accessions that are available to generate basal information that could be used for the crop cultivation and improvement Although Nigeria is one of the leading producers of sesame in Africa, there is insufficient information on the diversity of sesame accessions in cultivation, hence only a little progress is made on sesame breeding and the devel- opment of elite cultivars in the country. To improve ses- ame production for seed and oil yield in Nigeria, there is a need for characterization, performance evaluation and assessment of genetic diversity of the available genotypes. To this end, the present study assessed the performance, morphometric variation, and proximate composition of eleven accessions of cultivated sesame (S. indicum) in the Kwara State of Nigeria with the view of identifying and selecting the best and promising accessions in terms of yield and nutritional quality that could be improved for higher productivity. 2 MATERIALS AND METHODS 2.1 COLLECTION OF THE SESAME ACCESSION Eleven accessions of Sesamum indicum L. collected from the National Centre for Genetic Resources and Biotechnology (NACGRAB), Ibadan, Oyo State, Nigeria were used for the study. NACGAB is the National Agen- cy responsible for the collection, evaluation and conser- vation of genetic resources in Nigeria. The accessions (Igboho black, 02M, 03M, E8, 01M, Exsudan, Kenan 4, Acta agriculturae Slovenica, 118/1 – 2022 3 Performance and genetic diversity of some sesame (Sesamum indicum L.) accessions ... in Kwara State of Nigeria NGB00960, NGB00963, Bogoro local and NGB00390) are part of the mini-core collection of cultivated sesame from the growing regions of Nigeria. The collections are maintained at NACGRAB genebank facility (All in- formation and details of the accessions are available at NACGRAB, Nigeria). 2.2 THE EXPERIMENTAL SITE The pot experiment was conducted at the Univer- sity of Ilorin Botanical Garden, Ilorin, Kwara State, Ni- geria. The garden is at the Latitude 8° 24ʹN - 8o 36ʹN and Longitude 4°10ʹE - 4° 36ʹE in the Guinea savanna zone of Nigeria. The annual rainfall is 990-1200 mm and the temperature is between 33 – 37 oC (Olaniran, 1988; Ajadi et al., 2011). The relative humidity is about 75 % during the rainy season, and 65 % during the dry season. During the dry season (November – May), the sun shines for 6.5 - 7.5 hours per day (NIMET, 2018) Ten clean and healthy seeds of each accession were sown separately into a pot (30 × 25 cm), filled with loose soil taken from 0-15 cm soil depth, from a location with distinct textural characteristics of sandy-loamy in the garden. The experiment was laid out in a complete rand- omized design (CRD) with 0.5 m between the pots in five replicates for each accession in a screen house facility. On germination, the seedlings were thinned to 2 plants per pot. Adequate watering and weeding practices were car- ried out as required. Meanwhile, no fertilizer or nutrient supplement was added to the plant through the weeks of evaluation. The performance of the accessions was evalu- ated at two-week intervals until 14 weeks after sowing (WAS) using the International Plant Genetic Resources (IPGRI, 2004) descriptors for sesame. The growth varia- bles evaluated include; plant height, number of leaves per plant, leaf dimension, petiole length, number of primary branches and stem girth. Furthermore, at maturity data were collected on the flowers and seed related characters such as days to 50  % flowering, the number of flowers per plant, number of capsules per plant, capsule length and width, 1000-seed mass and mass of seeds per plant. Qualitative characters such as stem base colour, leaf and flower colour, seed colour and shape were also recorded. 2.3 CHLOROPHYLL AND CAROTENOID DETER- MINATION The photosynthetic pigment extraction and quan- tification were carried out as described by Porra et al. (1989). Fresh leaf samples collected from the accessions early in the morning were used for the pigment analy- sis. In brief, chlorophyll extraction was performed by dipping 12.5 mg of each leaf sample into a sample bottle containing 3.5 ml acetone in five replicates. The set-up was left for 72 hours in a dark cupboard at room temper- ature, after 72 hours, the bottle was vigorously shaken, and then the bleached leaf was removed, leaving behind the leaf homogenates in the bottle. The chlorophyll and carotenoid contents were quantified using a spectropho- tometer (Jenway, Model 6305, Bibby Scientific, USA). The amount of chlorophylls a, b, carotenoid, and total chlorophyll was calculated using the Porra et al. (1998) equations: - Chlorophyll a (mg ml-1) = [(12.21 x A663) – (2.81 x A646)] - Chlorophyll b (mg ml-1) = [(20.13 x A646) – (5.03 x A663)] - Total chlorophyll = Chlorophyll a + Chlorophyll b - Carotenoids = [(1000 x A470) – (3.27 x Chl.a) – (104 x Chl.b)] / 198 Where A is the absorbance wavelength read from the Spectrophotometer. 2.4 DETERMINATION OF THE PROXIMATE COMPOSITION OF SESAME SEED The proximate analysis followed the standard pro- tocol of AOAC (2000). The moisture content was deter- mined by oven-drying the seeds at 105 oC for 24 hours. The dried seeds were grounded and the moisture con- tent was estimated. Crude lipid was extracted from the samples with petroleum ether as solvent using the Sox- hlet apparatus technique, then the percentage crude li- pid was determined as described in the protocol (AOAC, 2000). The nitrogen composition was determined by Micro-Kjeldahl’s method using Electrothermal (Model MQ3868B/E, Fisher Scientific, Austria). The total nitro- gen was estimated using the relationship N x 5.95, and the resultant values are taken as the percentage crude protein of the seeds. The percentage of fibre and ash con- tents (% minerals) was also obtained using a standard procedure (AOAC, 2000). The total carbohydrate present in the seeds was derived by the differential method as: % Total carbohydrate = 100 – (% moisture + % crude protein + % crude lipid + % ash + % crude fibre) 2.5 STATISTICAL ANALYSIS Data collected were subjected to Analysis of Vari- ance (ANOVA) using SPSS statistical package version 21. The means were separated by New Duncan’s Multiple Range Test (N-DMRT), and the probability value of 0.05 Acta agriculturae Slovenica, 118/1 – 20224 D. A. ANIMASAUN et al. was used as a benchmark for separating a significant dif- ference in the means. Growth and yield parameters were correlated using Genstat 19th Edition (Payne et al., 2007). Genetic relationship and cluster analysis were conducted, based on the agglomerative technique of the unweighted pair group of arithmetic average (UPGMA) method. The genetic relationships of the accessions were graphically presented as a dendrogram. 3 RESULTS 3.1 QUANTITATIVE GROWTH PARAMETERS OF THE ACCESSIONS The plant height varied across the weeks of evalua- tion (Fig. 1). The average plant height for the accessions are 2.45, 7.85, 21.11, 43.79, 57.61 and 61.03 cm for 2, 4, 6, 8, 10 and 12 WAS respectively. Accessions 02M, Kenan 4 and 01M had the best growth performance across the weeks. Four accessions (Igboho Black, 03M, E8 and Ex- sudan) recorded plant height below the average over the period (Figure 1a). At 2 WAS, ‘Bogoro Local’ had a 6.0 mean number of leaves per plant which is far higher than the average of 3.60 leaves per accession (Fig 1b). At the same time, ‘Exsudan’ had 1.60 leaves per plant. Similarly, at 4-12 WAS, ‘Bogoro Local’ maintained the best perfor- mance in terms of leaf formation while ‘Exsudan’ showed the least. Other accessions that exhibit good leaf forma- tion are; Igoho Black, NGB00390 and 01M. Meanwhile, 03M, E8 and NGB00963 had the number of leaves less than the average. However, a fall was recorded for most Figure 1: Growth parameters (2 – 12 weeks after sowing) of the eleven accessions of Sesamum indicum evaluated for variability and genetic diversity of accessions. Kenan 4 and 00960 were the first to begin senescence, observed from the 10 WAS, followed by six accessions (Bogoro Local, 00963, Kenan 4, 02M, NGB00960 and 03M) at 12 WAS with a corresponding decrease in stem girth. Bogoro Local had the highest number of primary branches, an average of 9.60, closely followed by Igboho black (6.65), 01M and NGB00960 both having 5.33. Altogether, Eksudan and 03M had the poorest performance in quantitative characters observed Acta agriculturae Slovenica, 118/1 – 2022 5 Performance and genetic diversity of some sesame (Sesamum indicum L.) accessions ... in Kwara State of Nigeria accessions at 10-12 WAS, indicating the inception of se- nescence. The petiole length was progressive till 10 WAS (Fig 1c). Five accessions (01M, 02M, Kena 4, NGB00960 and NGB00963) consistently had petiole length higher than the average. Worthy of mention is that ‘Exsudan’ which had the least number of leaves per plant also had the short- est petiole. The accessions were diverse in leaf area which did not follow a definite trend, though most accessions’ leaf area was above the average (Fig 1d). However, at 8-12 WAS, ‘01M’ had the largest assimilative surface followed by ‘02M’ and ‘Bogoro Local’. The least leaf area occurred in ‘Exsudan’ over the period. No branching occurred in the accessions at 2-4 WAS except ‘Bogoro Local’ that had 1.20 branches per plant. Only two accessions (NGB00960 and Bogoro Local’) had the number of branches ≥ 4.0 per plant at 6 WAS, even at 8 WAS, only 1.80 branches were found on ‘Exsudan ‘and 03M. More branches were ob- served in ‘Igboho’ black at 6-8 WAS reaching its peak in week 8 (6.60). Generally, the average number of branches for the accession was low across the weeks of evaluation (Fig 1e). Most accessions fell below the average, only four (Igboho Black, 01M, NGB00960 and Bogoro Local) had a higher number of branches. The stem diameter of the accessions progressed with the week of evaluation, with most accessions recording stem diameter above average, the least occurred in ‘Exsudan’ (Fig 1f). At maturity, growth parameters varied significantly (p < 0.05) for the accessions (Table 1). The average plant height of the accessions was 62.19 cm, ‘Igboho Black’, ‘03M’, ‘E8’, ‘Exsudan’, and ‘Bogoro Local’ plants are signif- icantly short. The tallest accession (94.84 cm) was 02 M, while the Exsudan was the shortest (27.76 cm). Whereas ‘Bogoro Local’ was the best in terms of leaf formation with over 78 leaves per plant which is significantly higher than the accessions’ average (31.54). In contrast, ‘Exsu- dan’ showed poor performance with just 8.66 leaves per plant. The accessions petiole length ranged from 1.60 to 6.01 cm, five accessions had petiole lengths greater than the average (3.85 cm), and the longest occurred in ‘NBG00390’. Accession 01M produced leaves with the highest surface area (43.06 cm2). The ‘Exsudan’ which had the least number of leaves and shortest petiole also produced the smallest assimilatory surface (14.91 cm2). The most branched of the accession is Goboro Local with over 9 branches per plant. There are other five accessions (Igboho Black, 01M, Kenan 4, 00960 and NGB00390) with more than 4 branches per plant. Branch forma- tion remained poor in ‘03M’, attaining only 1.90 primary branches per plant at maturity which is well below the average of all accessions (4.65). The stem girth of the ac- cessions was between 1.76 and 3.41 cm, while nine ac- cessions had stem girth > 2 cm, two accessions (03M and Exsudan) had less (Table 1). 3.2 YIELD ATTRIBUTES PERFORMANCE There are significant differences (p < 0.05) in the performance of the yield attributes of the sesame acces- sions. Among the accessions, E8 showed superior yield features (Table 2). Flowering was delayed in ‘NGB00390’ and ‘Exsudan’, both took longer days to attain 50 % flow- ering (54.25 and 50.11 days respectively). ‘E8’, ‘Bogoro Local’ and ‘Kenan 4’ attained 50  % flowering in 36.33, 37.35 and 39.56 days respectively, about a week earlier than the average (43.14 days) for the accessions. The av- erage number of days to attain physiological maturity for the accessions was 100.96 days which was not significant- ly different. Whereas, ‘NGB00390’ matured much earlier at 89.33 days. The last accession to reach maturity was 02M (108.66 days), followed by 03M (105.54 days) and NGB00960 (104.28 days). The highest number of capsules per plant (56.66) occurred in ‘E8’, followed by ‘Bogoro Local’ (54.02 capsules). Although the average number of capsules per plant for the accessions was 40.84, however, seven accessions (Igboho Black, 03M, 01M, NGB00960, NGB00963, Exsudan and NGB00390) produced less, and the least occurred in ‘NGB00390’ which produced 24.08 capsules per plant. Furthermore, the number of seeds per plant varied significantly (p ≤ 0.05) among the accessions. All acces- sions had more than 30 seeds in each capsule, with an average of 42.08 seeds per capsule. The highest seeds per capsule were recorded in ‘Bogoro Local’ (58.2 seeds), 10 seeds more than 02M (47.01 seeds) which is the second in the ranking. Fewer seeds per capsule were found in ‘NGB00390’ (34.10) which is not statistically different from ‘Exsudan’ (36.02). The average mass of a thousand seeds (MTS) of the accessions was 2.48 g. Three acces- sions (03M, Exsudan and NGB 00390) had MTS less than 2.00 g and the least obtained in ‘03M’ (1.22 g). Nev- ertheless, ‘E8’ produced the heaviest seeds (4.31 g), about 2.0 g more than the average for the accession. Besides, ‘E8’ had the highest (8.52 g) total mass of seeds per plant (TMSP), which means the accessions is superior in term of seed mass. Next to ‘E8’ was ‘Bogoro Local’ with 6.28 g TMSP. Both accessions also recorded the best capsule features, having capsules lengths of 2.23 and 2.58 cm, capsules width 0.64 and 0.92 cm respectively. In contrast, three accessions (03M, Exsudan and NGB00390 per- formed poorly for MTS and TMSP. Whereas the three accessions had capsule length and width below average, ‘NGB00390’ had the least capsule length of all the acces- Acta agriculturae Slovenica, 118/1 – 20226 D. A. ANIMASAUN et al. sions (1.68 cm), and ‘Exsudan’ with the least apsule width (0.58 cm) as presented in Table 2. The boxplot analysis (Fig. 2) revealed that the plant height of the accessions lies closer to the average (62.19 cm), the little deviation was accounted for greatly by ‘Exsudan’. The plots also showed that most accessions performed above the average in leaf formation, petiole length, the number of days to 50 % flowering, number of capsules per plant and number of seeds per capsule. The accessions’ performance aligned on the median val- ues for stem girth, days to maturity and the total mass of seeds per plant. For other characters such as the num- ber of primary branches, leaf areas, capsule length and breadth, most of the accessions performed below the av- erage. This indicates the presence of significant variation in both growth and yield characters of the accessions. 3.3 QUALITATIVE CHARACTERS The summary of the qualitative characters of the sesame accessions observed at maturity is presented in Table 3. The accessions leaf colour was either dark or light green. Only three accessions (Igboho Black, 02M and E8) exhibited dark-green leaves, others produced pale or light green leaves. The basal stem colour var- ied from greenish-brown, dark-green, pale green and green with specks of yellow. ‘03M’, ‘01M’, ‘Exsudan’ and ‘Kenan 4’, produced white flowers, ‘Bogoro Local’ and ‘Igboho Black’ had purple, ‘02M’, ‘E8’, ‘NGB00960’ and ‘NGB00963’ had milky-white while ‘NGB00390’ flowers are brownish white. The accessions’ capsules were elon- gated in shape and predominantly brown, enclosing nu- merous oval seeds which are either white, milky, brown or black (Table 3). 3.4 THE PRINCIPAL BIPLOT AND CORRELATION ANALYSES The principal biplot analysis of the agro-morpho- logical and seed related characters revealed that eight components (PC) contributed significantly to the ob- served variations among the sesame accessions. Out of the components, PC-1 and PC-2 which accounted for 45.17 and 20.25 % respectively, and cumulated to 65.42 % of the variables are the most important (Fig. 3). In the PC-1, plant height, the number of leaves per plant, num- ber of primary branches, leaf areas, number of capsules per plant, number of seeds per capsule and a thousand seed mass are the main sources of variation of the ac- cessions under PC-1. The variables that significantly con- tributed to the observed variation in the PC-2 are; plant height, petiole length, leaf area and the number of seeds per capsule. On the contrary, stem girth, number of days to 50 % flowering, days to maturity, capsule length and Accessions Plant height (cm) Number of leaves Petiole length (cm) Leaf Area (cm2) Number of primary branches Stem girth (cm) Igboho Black 56.80e 68.81b 3.12de 41.02a 6.65b 2.87cd 02M 94.84a 37.47d 5.01ab 38.74ab 3.60e 3.25ab 03M 41.28fg 12.80gh 3.33de 15.84f 1.90g 1.94f E8 44.84f 23.20ef 2.28ef 38.12ab 3.60e 2.09ef 01M 88.04ab 41.83c 5.51ab 43.06a 5.33bc 3.41a Exsudan 27.76h 8.66i 1.60g 14.91f 2.80ef 1.76f Kenan 4 84.24b 14.42g 3.50d 34.63cd 4.50de 3.02ab NGB960 69.84c 22.25ef 3.01e 36.02bc 5.33bc 3.01ab NGB963 68.20c 13.80g 4.50bc 34.10cd 2.60ef 2.29de Bogoro Local 41.72fg 78.45a 4.51bc 37.40bc 9.60a 2.49de NGB 00390 66.48cd 25.25ef 6.01a 24.87e 5.20bc 2.53cd Mean 62.19 31.54 3.85 32.61 4.65 2.61 Max 94.84 78.45 6.01 43.06 9.60 3.41 Min 27.76 8.66 1.60 14.91 1.90 1.76 Table 1: Vegetative growth variables of eleven accessions of Sesamum indicum at physiological maturity Values with the same letter(s) along a column are not significantly different at p < 0.05. The mean is the average for all the accessions, the Max is the maximum value and the Min is the minimum value for each parameter Acta agriculturae Slovenica, 118/1 – 2022 7 Performance and genetic diversity of some sesame (Sesamum indicum L.) accessions ... in Kwara State of Nigeria breadth are without significant effect. Thus, plant height, number of leaves, leaf area, days to flowering, days to ma- turity, number of capsules per plant, seeds per capsule and seed mass are the major factors of variation in the sesame accessions. The matrix of correlations between the vegetative and reproductive characters of the sesame accessions is presented in Figure 4. At a significant level of p < 0.01, the number of leaves is associated with the number of prima- ry branches (r = 0.8701). Also, a strong positive correla- tion occurred between capsule length and the number of seeds per capsule (r = 0.8869); the number of capsules per plant, capsule width, and the number of seeds per cap- sules (r = 0.8393). Besides, the mass of a thousand seeds strongly related to the total mass of seeds per plant, and the total mass of seeds per plant was strongly linked with the number of capsules per plant (r = 0.9192). So also, is the number of primary branches and number of leaves (r = 0.8700); stem girth and plant height (r = 0.8803). Furthermore, at p < 0.05, plant height and leaf area (r = 0.5876), days to maturity and number of capsules per plant, the number of seeds per capsule and days to matu- rity, capsule length and days to maturity are linked (with r values above 0.4 and less than 0.8). Likewise, leaf area correlated with plant height, number of primary branch- es, number of leaves, number of capsules per plant and seed mass parameters. Other correlated characters are; the number of capsules per plant, number of seeds per Accession DT 50 % F DTM NCP NSC CL (cm) CD (cm) MTS (g) TMSP (g) Igboho Black 42.02b 98.45ab 37.10c 39.02b 2.01bc 0.62de 2.24bc 3.48d 02M 46.25ab 108.66a 44.21b 47.01ab 2.22ab 0.79b 2.76b 5.52ab 03M 42.05b 105.54a 39.33c 37.99b 1.89cd 0.68cd 1.22d 2.45de E8 36.33c 100.45a 56.66a 42.01ab 2.23ab 0.64d 4.31a 8.52a 01M 42.06b 101.25a 37.25c 38.02b 2.12bc 0.61de 2.20bc 4.42bc Exsudan 50.11a 98.28ab 28.44d 36.02c 2.02bc 0.58e 1.24d 2.01e Kenan 4 39.56bc 101.58a 51.33a 43.01ab 2.21ab 0.72bc 2.92ab 5.82a NGB00960 42.25b 104.28a 38.55c 38.02b 2.11bc 0.67cd 2.70b 3.95c NGB00963 42.33b 100.56a 38.25c 42.02ab 2.21ab 0.66cd 2.72b 4.02c Bogoro Local 37.35c 102.20a 54.02a 58.20a 2.58a 0.92a 2.96ab 6.28a NGB 00390 54.25a 89.33b 24.08d 34.10c 1.68d 0.72bc 1.96c 2.08e Average 43.45 100.68 40.77 42.08 2.12 0.70 2.52 4.54 Max 54.25 108.66 56.66 58.20 2.58 0.92 4.31 8.52 Min 36.33 8933 24.08 34.10 1.68 0.58 1.22 2.01 Table 2: Yield attributes of seed related characters of eleven accessions of Sesamum indicum evaluated for variability and genetic diversity study at maturity Values with the same letter(s) along a column are not significantly different at p < 0.05. The mean is the average for all the accessions, the Max is the maximum value and the Min is the minimum value for each parameter. DT 50 % F: Days to 50 % flowering; DTM: Days to physiological maturity; NCP: Number of capsules per plant; NSC: Number of seeds per capsule; CL: capsule length; CW: capsule width; MTS: Mass of a thousand seeds per plant; TMSP: Total mass of seeds per plant Fig 2: The boxplot of the growth and reproductive characters of eleven accessions of Sesamum indicum evaluated for perfor- mance and genetic diversity. The boxes revealed the skewness of the data from the mean proportion of the studied acces- sions with values below or above the mean. The y-axis shows the magnitude of the measured characters while the x-axis contains the characters total chlorophyll (6.32 mg l-1) (Fig. 5), followed by ‘Bo- goro Local’, ‘NGB00390’, ‘NGB00960’, and ‘02M’ which all had chlorophyll-a > 3.00 mg l-1. and chlorophyll-b > 4.00 mg l-1. At the same period, ‘01M’ had the least to- tal chlorophyll (1.65 mg l-1). Likewise, the highest carot- enoid content (1.21 mg l-1) was found in ‘Exsudan’. Four accessions (03M, Igboho Black, E8 and 01M) had carot- enoid content < 0.70 mg l-1. Chlorophyll-b was generally low at the seedling stage, although notably high in ‘Ex- sudan’ (1.54 mg l-1), ‘01M’ recorded the least amount of the pigments. At 8 WAS, the total chlorophyll content of the ac- cessions increased for some accessions, ‘Exsudan’ yet had the highest chlorophyll (11.56 mg l-1) (Fig. 5). The carot- enoid contents of all the accessions were similar except ‘NGB00960’ and ‘NGB00963’ which showed a decline. Carotenoid increased as much as 43 % in ‘01M’, and ‘Ex- sudan’ by 25 %, amounting to 1.58 mg l-1 which was the highest recorded while the accession NGB00963 record- ed the least carotenoid (0.38 mg l-1). Although, the total chlorophyll contents of the accessions are similar, not- Acta agriculturae Slovenica, 118/1 – 20228 D. A. ANIMASAUN et al. plant and capsule dimension. More associations of sig- nificant interaction between the morphometric and seed related characters are shown in Figure 5. However, a neg- ative correlation (r < 0) existed between the number of days to 50 % flowering and the number of seeds, capsules per plant, capsule length, and mass of seeds. There was approximately no correlation between plant height and the number of seeds per plant, number of leaves and the number of primary branches. 3.5 PHOTOSYNTHETIC PIGMENTS CONTENT Chlorophyll analysis was conducted on each acces- sion every four (4) weeks till maturity to determine the quantity and variations in chlorophyll a, b, and carote- noids contents. Over the period of vegetative growth (2- 12 WAS), chlorophyll-a was relatively more abundant in the leaf compared to other photosynthetic pigments (Fig. 5). At 4 WAS, ‘Exsudan’ had the highest chlorophyll-a (4.78 mg l-1) and chlorophyll-b (1.54 mg l-1), same for the Accession Leaf colour Stem base colour Flower colour Capsule colour Capsule shape Seed shape Seed colour Igboho Black Dark green Greenish brown Whitish purple Brown Elongated Oval Black 02M Dark green Yellowish green Milky white Brown Elongated Oval Milky white 03M Light green Dark green White Brown Elongated Oval Milky white E8 Dark green Dark green Milky white Brown Elongated Oval Milky white 01M Light green Light green White Brown Elongated Oval White Exsudan Light green Light green White Greenish brown Elongated Oval White Kenan 4 Light green Greenish white White Greenish brown Elongated Oval White NGB00960 Light green Greenish white Milky white Greenish brown Elongated Oval Milky white NGB00963 Light green Light green Milky white Brown Elongated Oval Milky white Bogoro Local Light green Greenish- white Purple Yellowish- brown Elongated Oval Brownish- yellow NGB00390 Yellowish green Yellowish green Brownish white Brown Elongated Oval Brownish- yellow Table 3: Summary of the qualitative characters of eleven accessions of sesame for similarities and differences in their morphologi- cal features at maturity Values with the same letter(s) along a column are not significantly different at p < 0.05. The mean is the average for all the accessions, the Max is the maximum value and the Min is the minimum value for each parameter Acta agriculturae Slovenica, 118/1 – 2022 9 Performance and genetic diversity of some sesame (Sesamum indicum L.) accessions ... in Kwara State of Nigeria Fig. 3: The principal biplot of PC-1 vs PC-2 of contributions of the growth and seed related parameters to the observed varia- tions in eleven accessions of cultivated sesame. Eight attributes contributed significantly to the observed variation of which PC-1 and PC-2 accounted for 65.42 % cumulative effects. The direction of the arrows shows the loading effects of the param- eters in marking the variation among the accessions Fig. 4: The matrix of correlations between the vegetative and reproductive characters of the eleven sesame accessions evalu- ated for performance and genetic diversity. The deep brown coloured signifies significant trait associations at p < 0.01 with r values ≥ 0.75, light brown shows significant trait associa- tion at p < 0.05 with r values ≥ 0.45 ≤ 0.74. The yellow colour had r values ≥ 0.02 ≤ 0.30. DT 50 % F: Days to 50 % flower- ing; DTM: Days to physiological maturity; NCP: Number of capsules per plant; NSC: Number of seeds per capsule; CL: Capsule length; CW: Capsule width; MTS: Mass of a thousand seeds per plant; TMSP: Total mass of seeds per plant withstanding, ‘Exsudan’ had the highest total chlorophyll (11.57 mg l-1). Chlorophyll contents of ‘Exsudan’, ‘03M’ and ‘Bogoro Local’ are at per at 12 WAS, and the trio re- Fig. 5: Chlorophyll and carotenoid contents of eleven acces- sions of Sesamum indicum evaluated for performance and genetic diversity at 4, 8 and 12 weeks after sowing corded the highest. Likewise, ‘Kenan 4’ and ‘01M’ had a statistically similar amount of carotenoid. Whereas the lowest (0.73 mg l-1) occurred in ‘NGB00960’, ‘Exsudan’ has the highest chlorophyll-a (8.37 mg l-1) and b (4.35 mg l-1). At maturity, ‘03M’, ‘Exsudan’ and ‘Bogoro Local’ are not significantly different in carotenoid contents. ‘Exsu- dan’ had the highest total chlorophyll (12.87 mg l-1) with chlorophyll-a, and b contents of 8.31 mg l-1 and 4.56 mg l-1 respectively. All through the study, ‘Exsudan’ had the highest photosynthetic pigments content (chlorophyll-a, b and carotenoids) among the accessions. However, there was a general decline in the synthesis of the plant pig- ments. 3.6 PROXIMATE COMPOSITION OF THE ACCES- SIONS The proximate composition of the sesame acces- sions varied significantly (p ≤ 0.05) as shown in Ta- ble 4. ‘Igboho Black’ and ‘E8’ had the highest moisture 10 D. A. ANIMASAUN et al. Acta agriculturae Slovenica, 118/1 – 2022 contents of 3.40 % and 3.38 % respectively, followed by ‘03M’ (3.25 %), ‘01M’ (3.20 %), ‘Eksudan (3.18 %), and ‘NGB00390’ (3.15  %). Whereas moisture contents of ‘01M’, ‘Eksudan’ and ‘NGB00390’ are not statistically similar, the least amount of moisture (2.03 %) was found in ‘NGB00963’. The ash content which indicates the min- eral element composition of the accessions ranged was 4.55- 5.98  %, only two accessions, Igboho Black and 03M had ash composition above 5  %. Like the mois- ture content, the least percentage of the mineral was found in ‘NGB00963’. Generally, all the accessions had a percentage crude protein higher than 5  %, the high- est (7.4 %) occurred in ‘00960’ and the lowest (5.33 %) in ‘02M’. The highest crude fibre content was found in ‘Igboho Black’ (5.77 %), followed by ‘E8’ (4.99 %), none of the accessions had crude fibre composition of less than 4  %. Furthermore, there is variation in the fat and oil composition of the accessions. Sesame seeds are main- ly used for oil production; therefore, the percentage of oil composition is important. The accession E8 had the highest oil yield (60.5 %) which was not significantly dif- ferent from the percentage composition of fat and oil in ‘Kenan 4’ (60.45  %). Meanwhile, none of the accession recorded crude fat and oil percentage less than 50 %, the least (53.61  %) was found in ‘Igboho Black’. As an oil- bearing crop, the carbohydrate composition was expect- edly low, ranging from 18.81-28.62 %. The accessions E8 Accession Percentage composition (%) Moisture Ash Crude protein Crude fibre Fat and oil Carbohydrate Igboho Black 3.40a 5.98a 5.60g 5.77a 53.61j 27.63b 02M 3.10e 4.84cd 5.33i 4.69e 57.25e 24.79c 03M 3.25b 4.97bc 5.80h 4.75d 59.83b 21.49e E8 3.38a 5.10b 7.21c 4.99b 60.50a 18.81h 01M 3.20bc 4.92bc 7.35ab 4.81bc 58.76d 21.47e Exsudan 3.18cd 4.85cd 6.80e 4.78cd 58.95c 21.33f Kenan 4 2.68g 4.60ef 6.90d 4.49g 60.46a 20.79g NGB00960 2.74f 4.80d 7.40a 4.62f 56.80f 23.76d NGB00963 2.03i 4.55ef 5.85g 4.38h 54.47h 28.62a Bogoro Local 2.04h 4.65e 6.58f 4.47g 54.25i 27.62b NGB00390 3.15d 4.88cd 6.81e 4.80c 55.58g 24.79c Table 4: Proximate composition of the eleven accessions of Sesamum indicum evaluated for variability and genetic diversity Values with the same letter(s) along a column are not significantly different at p < 0.05 and Kenan 4 with high fat and oil had 18.81 and 20.79 % carbohydrate respectively. The percentage of fat and oil composition of the accessions was inversely proportional to the carbohydrate content (Table 4). 3.7 DIVERSITY OF THE ACCESSIONS The dendrogram partitioned the accessions into two major groups (Fig. 6). Group 1 consisted of two acces- sions; Igboho black and Bogoro Local which are sepa- rated at a genetic distance below 24. Group 2 consisting of 9 accessions was further divided into two sub-groups; 2A and 2B. The sub-group 2A had three accessions sepa- rated into two clusters; 2A(i) and 2A(ii) at a genetic dis- tance below 34, a single accession (E8) made the cluster 2A(i) while two accessions (03M and Exsudan) with dis- tance scale of 15 constituted the cluster 2A(ii). On the other hand, the sub-group 2B members were segregated into two distinct clusters; 2B(i) and 2B(ii). The former comprised of four accessions (NGB00390, Kenan 4, NGB00960 and NGB00963), whereas ‘NGB00390’ was the most distant member, followed by ‘Kenan 4’ with less genetic distance while the duo of ‘NGB00960’ and ‘NGB00963’ are the most related members of the clus- ter. Besides, two other related accessions, 02M and 01M formed the clustered 2B(ii). 11 Performance and genetic diversity of some sesame (Sesamum indicum L.) accessions ... in Kwara State of Nigeria Acta agriculturae Slovenica, 118/1 – 2022 4 DISCUSSION The qualitative and quantitative traits of the acces- sions revealed variations in the studied variables, this showed there is existing genetic diversity amidst the ac- cessions. Factors such as genetic drift, natural and arti- ficial selection, exchange of breeding materials could contribute significantly to diversity among the acces- sions. (Sabesan et al., 2009; Banumathy et al., 2010). The observed variability in the morphological attributes ob- tained in the present study could provide useful infor- mation for the identification and selection of accessions with superior traits that could be used for sesame pro- duction, and as parents for breeding programs (Arriel et al., 2007). Significant dissimilarities in parameters such as plant height, leaf attributes, and stem girth as well as yield-related characters are essential for the assessment of variability and genetic divergence in plant genetic re- sources (Bisht et al., 1998; Baydar, 2005; Sharmila et al., 2007; Furat & Uzun, 2010; Kiranmayi et al., 2016; Ani- masaun et al., 2017; Azeez et al., 2017; Iqbal et al., 2018; Adu-Gyamfi et al., 2019). The significant differences in the growth and yield characters of the evaluated Sesamum indicum accessions concurred with earlier reports (Adebisi et al., 2005; Par- ameshwarappa et al., 2010; Pham et al., 2010). The ob- served differences may be due to the genetic system of Figure 6: Dendrogram of the genetic relationship of the eleven sesame accessions based on agro-morphometric and yield-related attributes. The dendrogram was constructed using the agglomerative technique of the unweighted pair group of arithmetic average (UPGMA) method the accessions. The plant height range (27.76-94.84 cm) of the accessions in the current study was lower than 104-161 cm reported for some genotypes in South-East Asia by Pham et al. (2010). In terms of growth attributes, ‘02M’ and ‘Kenan 4’ are the most promising accessions. Although ‘Bogoro Local’, ‘E8’, ‘03M’ and ‘Igboho’ black had heights below the accessions average, notwithstand- ing, they had good yield attributes suggesting that veg- etative growth and grain yield are under different ge- netic control systems. The short accessions may not be a complete disadvantage as Baydar (2005), opined that non-branching sesame varieties of medium heights and uniform maturity may be desirable for mechanized cul- tivation, and development of modern sesame breeding programmes. In addition, shorter canopy might lead to redistribution of assimilate which promotes higher yield. The ability of the accessions to achieve 50 % flower- ing between 37 to 54 days showed most of the accessions are elite with regards to maturity. In a similar study, Ar- riel et al. (2007) reported the commencement of flower- ing varied from 30 to 48 days in some accessions. Also, the 89-108 days to maturity reported in the current study agreed with the authors’ report. Meanwhile, Pham et al. (2010) documented much earlier time (24-31 days) for some accessions. The accession E8 that attained early ma- turity in this study could be potential mother material for the development of elite sesame cultivars. Since sesame is cultivated mainly for its seed and oil, therefore, seed yield attributes are of great importance in the selection of accession for commercial production. Besides early maturity, accession E8 showed impressive yield-related traits. According to Parameshwarappa et al. (2010), sesa- me genotypes with delayed maturity may record low seed yields. This is true for this study; ‘NGB00390’ which at- tained maturity late also had poor seed yield. Compared to other oilseed crops, sesame yield is low owing to its early senescence and vulnerability to some abiotic stress and photosensitivity (Pathak et al., 2014). Also, legumes generally have low yield, since the construction cost of oil is high compared to that of the carbohydrates in ce- reals. The high seed mass of ‘E8’ further reinforced the good quality of its seeds, making it a good parent mate- rial for sesame breeding programmes. The variations in the number of capsules per plant and seeds per capsule obtained in this study corroborate the earlier works (Og- bonna & Ukaan, 2012), who demonstrated considerable variation in some sesame seed characters, and this sug- gest yield component are controlled by multiple genes (Basu et al., 2009). In green plants, the assimilatory surface is one of the major factors that determine growth and yield (Beheshti & Fard, 2010). Thus, a larger and increased assimilatory surface may translate to higher photosynthate, and ulti- 12 D. A. ANIMASAUN et al. Acta agriculturae Slovenica, 118/1 – 2022 mately a better growth and yield. Sesame is highly sensi- tive to day length which coupled with temperature have a significant effect on its flowering rate (Suddihiyam et al. 1992). There is a close correlation between photosyn- thetic active radiation (PAR) absorption and yield (Ya- dav et al. 1988). But the reverse is the case for the duo of ‘Exsudan’ and ‘NGB00960’, which despite their high chlorophyll contents, they performed poorly in growth and yield. This suggests the two accessions had inher- ent characters for their non-impressive performance and therefore may not be suitable as raw material for the crop improvement. The gradual decline in chlorophyll contents of the accessions after 10 WAS could be due to increasing senescence, as the plant shift from the vegeta- tive growth phase to the reproductive and maturity stage, this, of course, explains the slight increase recorded in the carotenoid contents. Carotenoids are essential pig- ments that compliment chlorophyll, it also acts as photo- protectors, antioxidants, colour attractants, and precur- sors of plant hormones in non-photosynthetic organs of plants. As the plant attains maturity and gene switches from vegetative to reproductive phase, more carotenoids are produced to manage the decrease in the Chlorophyll a and b functionality. In addition, carotenes contribute to photosynthesis by transmitting the light energy they absorb to chlorophyll and protect plant tissues by help- ing to absorb the energy from singlet oxygen, an exciting form of the oxygen molecule O2 which is formed during photosynthesis. Traits that are significantly correlated are highly linked and are possibly controlled by a genetic system. The strong associations between plant height, leaf area and seed yield showed there is a connection between growth and yield components. Significant correlations have been established in crop plants (Kiranmayi et al., 2016; Animasaun, et al., 2021; Azeez et al., 2017; Olo- runmaiye et al., 2019), in all cases, it was argued that traits that are correlated are linked, and can be improved simultaneously. Meanwhile, Parameshwarappa et al. (2010), reported a negative relationship between the number of days to 50 % flowering and seed yield, indi- cating the higher the number of days to flower, the less the seed yield. Characters that showed significant nega- tive association are not genetically linked and may be im- proved or selected individually. The concept of correlated traits is of great importance to a breeder as it gives con- cise information on character linkage on which selection could be made. The nutrient composition of the seeds also varied, oil yield was generally high above 50 % in all accessions, a bit higher than values reported by Kiranmayi et al. (2016). The high oil yield obtained from ‘E8’ and ‘Kenan 4’, makes them the potential candidates for improved oil yield breeding programmes. The low carbohydrate con- tents of the accessions qualify the seed oil as low calories and safe for human and animal health. The Principal Component Biplot Analysis enables the plant breeders to sort genotypes and select promis- ing varieties using multivariate methods to estimate the contribution of each trait that constitute an ideal plant (Yan & Rajcan, 2002, Iqbal et al., 2018). Thus, it is an important tool to reveal the degree of similarity or vari- ability among evaluated accessions. The effectiveness of a trait as a morphological marker is measured by its dis- criminating power among the accessions and its stability of expression (Arriel et al., 2007). The presence of ‘02M’ and ‘01M’ on a plain revealed they had similar morpho- logical traits. They are both tall, with a relatively similar number of leaves per plant. The co-occurrence of three accessions; E8, 03M, and Exsudan in a cluster indicates a shared resemblance in yield characteristics. Related- ness and genetic diversity among the accessions based on growth and yield characters were further established by the dendrogram, which partitioned the accessions into four distinct groups. The higher the genetic distance, the less the relatedness, consequently, accessions having less distance scale are more related. The dendrogram ob- tained in the present study revealed that ‘NGB00960’ and ‘NGB00963’ are the most related accessions, and they are distant relative to ‘Kenan 4’. A similar study (Tyagi et al., 2014) also demonstrated heterogeneous genotypes in a cluster, because, genetic relationship is based on related genetic markers and not necessarily the origin of the accessions (Animasaun et al., 2015). The use of cluster analysis to unravel genetic similarity in crop genetic re- sources have been demonstrated (Adewale et al., 2015; Pandy et al., 2015; Animasaun et al., 2017). The genetic divergence information present by the dendrogram is of great importance because it reveals accessions that are likely from a common progenitor. Besides, such infor- mation is a prerequisite for the selection and breeding of improved cultivars with novel alleles mix as well as devel- oping an effective conservation strategy for the genetics (Upadhyay et al., 2011). Since members of a cluster share similar genetic composition regardless of origin, there- fore, duplication and misidentification of accessions can be prevented. 5 CONCLUSION The current study evaluated the performance and assessed the genetic diversity of eleven accessions of cul- tivated sesame using morpho-agronomic traits, photo- synthetic pigment and nutrient composition. The result showed significant variations among the accessions for 13 Performance and genetic diversity of some sesame (Sesamum indicum L.) accessions ... in Kwara State of Nigeria Acta agriculturae Slovenica, 118/1 – 2022 growth, seed yield and nutritional composition. In terms of growth attributes, ‘02M’ and ‘Kenan 4’ are the most promising while ‘E8’, ‘Bogoro Local’, and ‘Igboho Black’ showed good yield attributes. However, ‘Kenan 4’ showed the optimum performance. The study concludes that the accessions are genetically and phenotypically diverse and the existing diversity could be harnessed for selecting high yielding and adaptable variety as possible parents for the development of improved cultivars for commer- cial cultivation. 6 ACKNOWLEDGEMENTS The authors are grateful to the Management of the National Centre for Genetic Recourses and Biotechnol- ogy (NACGRAB), Ibadan Nigeria for providing the sesa- me accessions used for this study. 7 CONFLICT OF INTEREST The authors declare there is no potential conflict of interest. 8 FUNDING INFORMATION We received no funding for the study. 9 REFERENCES A.O.A.C (Association of Official Analytical Chemists) (2000). Official Methods of Analysis, Washington D.C. Adebisi, M.A., Ajala, M.O., Ojo, D.K., & Salau, A.W. (2005). Influence of population density and season on seed yield and its components in Nigeria sesame genotypes. Journal of Tropical Agriculture, 43(2), 13-18. Adewale, B. 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