YIELD AND NUT QUALITY OF 29 CASHEW MOTHER TREES (ANACARDIUM OCCIDENTALE L) ESTABLISHED AT THE GERMPLASM OF OUOGHI IN CENTRAL REGION OF BENIN

Description of subject: One of the main constraints to cashew crop development in Benin and Africa is the unavailability of efficient planting material for the plantations establishment. This constraint is largely responsible for the low level of nut yieldsobtained in cashew plantations. Objective: This study aimed to assess the agronomic performances of 29 different cashew mother trees established in the germplasm of the Central Agricultural Research Center (CRA-Centre) of the National Agricultural Research Institute of Benin located in Save, Central region, in sightof selecting high-performance clones to be distributed in rural areas. Materials and Methods: Nuts production, unit nuts weight and the kernelrate data were collected on 29 cashew mother trees during the harvest seasons from 2017 to 2020. These data were submitted to the analysis of variance and comparison of the means tests with software R. Results: The average nut yields of the 29 cashew mother trees varied from 0.85 to 11.98 kg / tree with a general average of 3.57 kg / tree at the age of 7 years old. Average unit nut weights ranged from 4.61 to 8.28 g with an overall average of 6.40 g. The average kernel ratio of nuts ranged from 24.08% to 32.46% with an overall average of 27.18%. The average weight of akernel varied from 1.43 to 2.15g with an average of 1.71g. At the end of the fouryears assessment, five of the 29 cashew mother trees with a minimum nut yield of 5 kg / tree were preselected as the first efficient cashew clones from Benin. Conclusion: These preliminary results are very important for the cashew breeding program in Benin. Furtherstudieswill plan to assess the cashew mother trees performance at 10, 15, 20 and 25 years old.

ISSN: 2320-5407 Int. J. Adv. Res. 8 (10), 1144-1152 1145 ………………………………………………………………………………………………… Introduction:-The cashew tree is nowadays an important export crop for the African continent which accounts for more than 55% of the world cashew nut production. Cashew nuts are an increasingly demanded export product on world markets and offer considerable potential for the industrial development of producing countries through local processing. Likewise, the economic potential of cashews offers opportunities throughout value chains. The cashew sector also allow to answer the current issues of climate change and migration (RONGEAD, 2015).West Africa had become the largest cashew production area in the world since 2015 with a production exceeding 1,350,000 tonnes (RONGEAD, 2015). In Benin, cashew nut production was 110,117 tonnes in 2017 (DSA / MAEP, 2017). The cultivated areas keep increasing year by year. They were estimated in 2015 at 285,568 ha (Adégbola and Crinot, 2016). Cashew nut contributes to 3% of the Gross National Product (GNP) and to 7.4% of the Gross Domestic Agricultural Product (GDAP); which raises it in 2nd position after the cotton sector which contributes to 25% of the GDAP (Tandjiékpon, 2010). Benin has large favorable areas for the cashew trees cultivation. Currently, cashew is produced in 5 of the 8 agro-ecological zones of Benin. These zones include 8 of the 12 departments of the country, namely: Alibori, Atacora, Borgou, Collines, Couffo, Donga, Plateau and Zou (Adégbola and Crinot, 2016). Despite these assets, the average nut yield of cashew trees remains very low (3 to 6 kg/tree) compared to that obtained in main producer countries in the world (10 to 15 kg/tree) such as India, Vietnam, Brazil and Tanzania (Masawe, 2010;Tandjiékpon, 2010). This low productivity of cashew trees considerably weakens the nut production and the incomes of growers, processors, traders and the State. This low productivity of cashew trees is due to several factors, including the insufficiency or lack of improved planting material (MAEP, 2011). It is to overcome this lack of improved planting material that a cashew breeding program started in Benin in 2011. This study addresses the intermediate results of this program. It presents the cashew nuts yields and the quality of nuts produced by 29 cashew mother trees established in the Ouoghi's germplasm in the Central region of Benin. The objective is to assess these 29 cashew mother trees performance at 7 years old and to pre-select the first cashew clones from Benin.

Material and methods:-Study area:
This study was conducted at Ouoghi in Savè Commune in the central region of Benin (figure 1). Savè Commune is in the agro-ecological zone V of Benin which is characterized by a Sudano-Guinean type climate with two rainy seasons in the South and a rainy season in the North with an average annual rainfall varying between 1,000 and 1,200 mm per year (Boko, 1992). But in recent years, this zone's climate has given way to a tropical Sudanese-type climate marked by a rainy season and a dry season (AFRIQUE CONSEIL, 2006). The average monthly water level varies from 7.1 mm in January to 223 mm in August. The average monthly temperature fluctuates between 24°C in July and 29°C in March (Akoègninou et al., 2006). The soils found there are tropical ferruginous soils. Hydromorphic soils are also observed in lowlands and river valleys. Overall, these different types of soils are relatively fertile (AFRIQUE CONSEIL, 2006).

Materials:-
The plant material used consists of 29 of the 30 cashew mother trees established in the Ouoghi's germplasm in August 2012. These cashew trees represent the best cashew mother trees identified in famer's plantations in 2011 (N'Djolossè, 2015). The plants used to establish this germplasm were produced by grafting. In germplasm, each cashew mother tree occupies a plot of 15 trees spread over 3 rows. The technical equipment used is composed of a 25 kg balance, 5 kg electronic balance, caliper and hornbill pliers. As agricultural equipment, jute bags, various sizes bags, gloves, alcohol and cotton were used.

Methodology:-
Being the second cash crop after cotton, the cashew tree has experienced a certain revival of interest in recent years in Benin through its nuts. Planting material is one of the key components for better yields. The study on the selection process of high-performance variety focuses on the nut yield per tree, the average weight of a nut, the average weight of a kernel and the average kernel rate according to studies done in other countries like Tanzania (Masawe, 2010). The used methods for each activity are as follows: Evaluation of nut yield from cashew mother trees: For the nut yields assessment from the different cashew mother trees, the produced nuts which fell under the trees were collected, tree per tree, dried and weighed. The nuts were harvested once a week from mid-January to the end of April of the years 2017, 2018, 2019 and 2020. Each year, the nut yield of each tree was obtained by summing the weights recorded during the various weighings during harvests.
Assessment of the quality of nuts produced by the cashew mother trees: The quality of the produced nuts was assessed in 2019 and 2020. To achieve this, three samples of 2 kg of nuts were taken per plot (cashew mother tree) at the peak of the harvest period (the beginning of March in 2019 and 2020). Each nuts sample was processed to determine the average weight of a nut, of a kernel, and kernel rate. The number of nuts in 1 kilogram was counted. To calculate the average weight of a nut, the weight of one kilogram of nuts was divided by the number of nuts. Then, each of the nuts in 1 kilogram was cut lengthwise using the hornbill pliers. Then, the kernel were collected with the skins and weighed. Finally, the kernel rate is determined by dividing the weight of the kernel by the total weight of the nuts.

Statistical analysis:
Analysis of variance were performed for each of the variables using R software, 3.5.0 version. The means comparisons and structuration were carried out using the Student-Newman-Keuls (SNK) test.

Results and Discussion:-
Nut yield from the different cashew mother trees: The average nut yields obtained for the 29 cashew mother trees assessed in Ouoghi's germplasm at the ages of 4, 5, 6 and 7 years old are presented in Table 1.
Analysis of variance carried out showed highly significant differences between these 29 cashew mother trees (P <0.0001) for the variable "nut yield" during the 4 years assessment. The analysis of Table 1 reveals the following observations: 1. The average nut yields obtained at 4 and 5 years old ages of the 29 cashew mother trees were generally very low and were less than 1 kg/tree. However, the SNK test carried out to compare the means made it possible to separate the cashew mother trees into three groups; 2. The average nut yields obtained at 7 years old age from the 29 cashew mother trees were at least two to ten times higher than the nut yields obtained at 4, 5 and 6 years old; 3. At 7 years old age, more than half of cashew mother trees have produced at least 4 kg of nuts per tree and at least 45% of cashew mother trees have at least 5 kg of nuts per tree; 4. At 7 years of age, the segregation of the cashew mother trees in relation to the variable "nut yield" was more pronounced. The SNK test carried out to compare the means allowed to go from 3 to 5 groups of cashew mother trees.

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The nut yields obtained for these cashew mother trees are very low compared to those obtained for the cashew clones selected in Tanzania (Masawe, 2006) and which varied from 4 to 15 kg/tree and from 8.48 to 24.84 kg/tree respectively for the ages of 4-5 and 7 years old.
These low nut yields obtained for the majority of the cashew mother trees under assessment are not necessarily linked to poor performance. They would also be due to the low rainfall recorded in the area since the establishment Quality of nuts produced by cashew mother trees: The quality of the nuts produced by the cashew mother tree was assessed at 6 and 7 years old using three parameters: the nut weight, the kernel weight and the kernel rate. The results of the nut quality assessment are shown in Tables 2, 3 and 4.
The average nut weight of cashew mother trees varying from 4.61 to 8.28 g with a general average of 6.40 g proves that we could have an average of 156 nuts per kg. In fact, the graining reflects the nuts average size. The greater number obtained, the more nuts are in a kg and the smaller they are. In the current study, the graining remains slightly higher than the selection criterion for genetic materials and improved mother trees compared to the graining which could vary between 100 to 150 nuts per kg (Masawe, 2016). This gives a good appreciation of the graining of these genotypes.
Analysis of variance carried out revealed highly significant differences between the 29 cashew mother trees (P <0.0001) for the two assessed parameters. The analysis of Table 2 shows: 1. A large inter-cashew mother trees variability for the two parameters used to assess nut quality. The SNK test carried out to compare the means allowed to separate the 29 cashew mother trees into more than 09 groups; 2. Most of the cashew mother trees studied produced good nut quality, at least two-thirds, as following: 1. only seven (7) cashew mother trees of the 29 had an average unit nut weight less than 6 g; and 2. two of the 29 cashew mother trees had a kernel rate less than 25%.  Savalou SLAZ01 6,289 l 6,100 j P < 0,0001 < 0,0001 In the same column, the numbers followed by the same letters are not significantly different at the 1% level.
1149 Table 3:-Average weight of kernels produced by cashew mother trees in Ouoghi's germplasm at 6 and 7 years old.

Sources of scions/mother trees Mean weight of a kernel (g) in 2019
Mean weight of a kernel (g) in 2020 N° Commune REFERENCE  Savalou SLAZ01 25,90 fg 24,04 l P < 0,0001 < 0,0001 In the same column, the numbers followed by the same letters are not significantly different at the 1% level.
The results of this study reveal that the average kernel rate in the nuts varied from 22.30% to 32.5% with an overall average of 27.18% in the 7th year. This average rate of 27.18 is similar to the results obtained by some authors. In Nigeria, Ogunwolu et al. (2016) recorded the following qualities: average out-turn of 47.53 lbs / 80 kg bag, average kernel rate of 25.33% with an average nut size of 181 nuts.kg -1 . The results obtained are in line with the observations of Masawe and Kapinga (2013a and 2013b) with regard to the kernel rate and graining. According to these authors, in cashew tree's breeding, it is strongly recommended to select mother trees with a kernel rate greater than 25%. According to these authors, genotypes (varieties, clones or hybrids) that have kernel rate greater than 25% are considered to be good genotypes. Cashew nut processing industries accept nuts with a graining less than or equal to 200 nuts.kg -1 or less (Masawe et al., 2015a). These authors pointed out that nuts with a graining greater than 200 nuts.kg -1 are difficult to process due to their small size.
Performance of the first preselected cashew clones in Benin: At the end of the first four years assessments, from 2017 to 2020, the first 5 efficient cashew clones in Benin were preselected by combining the 3 main parameters of yield and nuts quality. These first preselected clones produced at least 5 kg/tree at 7 years old. They had the best nut yields, but not necessarily the best nut qualities (Table 5). These yields are two to three times the national average yields recorded in farmers plantations in Benin, which were 2.28 and 4.06 kg/tree respectively for the age groups of 3 to 9 years old and 10 and 20 years old (DSA/MAEP, 2017).

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In addition to these first 5 pre-selected clones, four other clones present slight deficiencies in their nut quality (values highlighted in yellow). Future observations will allow to better appreciate and to confirm or not them as efficient clones of cashew trees in Benin. They will be also used in the breeding program by hybridization. Values highlighted in yellow present slight deficiencies In the same column, the numbers followed by the same letters are not significantly different at the 1% level.

Conclusion:-
The results of this study are the preliminary results of the assessment of the 29 cashew mother trees established in the Ouoghi's germplasm in the Central region of Benin. They made it possible to assess the productive performance of each cashew mother trees as well as the quality of the nuts that each of them produced. At the end of these first assessments, the first 5 efficient cashew clones of Benin which produced at least 5 kg of nuts per tree were preselected.The assessments of these cashew mother trees will continue in order to select the best cashew clones in Benin. At the same time, the important results of this study will be used to progress in the cashew breeding program in Benin by starting hybridization between clones and by implementing orchards for polyclonal cashew seeds production.