~ 9 ~ International Journal of Research in Agronomy 2020; 3(2): 09-21 E-ISSN: 2618-0618 P-ISSN: 2618-060X © Agronomy www.agronomyjournals.com 2020; 3(2): 09-21 Received: 06-05-2020 Accepted: 08-06-2020 Christopher Nyarukowa Department of Biochemistry, University of Pretoria, Private Bag X20, Hatfield, South Africa Mari van Reenen Human Metabolomics, North-West University (Potchefstroom Campus), South Africa Robert Koech Kenya Agriculture and Livestock Research Organisation, Tea Research Institute, P.O. Box Kericho, Kenya Samson Kamunya Kenya Agriculture and Livestock Research Organisation, Tea Research Institute, P.O. Box Kericho, Kenya Richard Mose James Finlay (Kenya) Limited, P.O. Box, Kericho, Kenya Zeno Apostolides Department of Biochemistry, University of Pretoria, Private Bag X20, Hatfield, South Africa Corresponding Author: Zeno Apostolides Department of Biochemistry, University of Pretoria, Private Bag X20, Hatfield, South Africa Multivariate models for identification of elite mother bushes with high commercial potential for black tea from mature seedling fields of Camellia sinensi Christopher Nyarukowa, Mari van Reenen, Robert Koech, Samson Kamunya, Richard Mose and Zeno Apostolides Abstract Tea producers are in demand of new high yielding cultivars, which produce high quality tea liquors. To breed for these phenotypic traits is challenging due to their polygenic disposition and influence by environment. Two C. sinensis populations, namely Comm cultivars from open pollinated field selections, and NComm cultivars from the reciprocal cross of two parents were used. These cultivars were employed to identify the metabolites responsible for distinguishing Comm cultivars, with high yield, high quality and DT from NComm cultivars that did not show these traits. PCA and PLS-DA models were constructed on UPLC/DAD data, which showed clear separation between the Comm and NComm cultivars. CHAID decision trees constructed aimed to classify the 303 genotypes as either Comm or NComm cultivars using subset of compounds. Breeders can predict the quality of new selections from mature seedling fields by employing CHAID decision trees, or the CAF/EC ratio, as predictors. Keywords: Camellia sinensis; catechin; metabolomics; theaflavin Introduction Tea (Camellia sinensis) is one of the most widely consumed beverages across the world (Hicks, 2009) [14] . The crop which originated in China is grown certain regions of Asia (India, China, Sri Lanka and Japan), Africa (Kenya, Uganda, and Malawi), and Latin America (Argentina). The tea beverage is prepared by brewing or boiling the dried tea leaves in water. Kenya is the world’s third largest producer of tea after India and China though it is the leading exporter of black Crush Tear and Curl (CTC) tea (Elbehri et al., 2015) [8] . The tea industry therefore contributes significantly to Kenya’s economy by contributing over 26% and 4% of total foreign exchange earnings and Gross Domestic Product (GDP), respectively (Kenya National Bureau of Statistics, 2012) [23] . Tea producers are in demand of new cultivars, which are high yielding, drought tolerant, and produce high quality tea liquors. Tea gets its distinctive astringent and somewhat bitter taste from caffeine (Horie et al., 1997) [17] , even though several other metabolites such as the catechins (catechin (CAT), epicatechin (EC), epicatechin gallate (ECg), epigallocatechin (EGC), and epigallocatechin gallate (EGCg)) and all other polyphenols, carbohydrates, and amino acids are influential in its overall taste and aroma (Adkins et al., 2007; Nyarukowa et al., 2016) [1] . The amino acid theanine, which makes up approximately two-thirds of a tea leaf’s total free amino acids content, is with other less abundant amino acids, responsible for the sweet and brothy “umami” taste of green tea (Vuong et al., 2011). However, it is noteworthy to indicate that the metabolite composition, which influences tea quality, varies between green and black tea. Unlike green tea, whose quality depends on amino acids, particularly theanine, catechins and caffeine, the quality of black tea depends on theaflavins (theaflavin (TF1), theaflavin-3-gallate (TF2), theaflavin-3’-gallate (TF3), and theaflavin-3,3’- digallate (T4)), thearubigins, catechins and caffeine (Le Gall et al., 2004) [26] . The four TFs are formed during black tea processing by oxidation of green tea catechins in presence of polyphenol oxidase as shown: (1) EC + EGC = TF1; (2) EC + EGCg = TF2; (3) ECg + EGC = TF3; (4) ECg + EGCg = TF4. This therefore indicates that the green leaf catechins are important and thus tea cultivars rich in catechins are likely to produce higher quality teas (Takemoto and Takemoto, 2018) [38] .