Genetic mapping and identification of quantitative trait loci for yield and drought tolerance in tea

Abstract

Accelerated breeding and selection of improved tea ( Camellia sinensis (L.) O. Kuntze) cultivars requires sound knowledge and understanding of genetics associated with desirable attributes. Quantitative trait loci ( Q TL) mapping for yield and drought tolerance in tea was performed using 42 F 1 clonal progeny derived from a cross between tea cultivars TRFCA SFS150 and AHP S15/10 that had been established at two distinct tea growing regions in Kenya. The 100 informative markers identified in the cross that exhibited 1:1 segregation ratio were used to construct a linkage map of tea. The map consisted of 30 (19 maternal and 11 paternal) linkage groups that spanned 1411.5 cM with mean interval of 14.7 cM between loci. Q TL analysis was carried out for yield and drought tolerance produced nine putative yield Q TLs and 13 Q TLs for drought tolerance. None of the Q TLs was congruently detected in the two sites owing to G x E interactions. Markers OPT-18- 2500 and OPO-02-900 had pleiotropic effects in that they were significantly associated with yield at Timbilil (YLD-T; P = 0.007) and drought tolerance at Kangaita (DT-K; P = 0.003). The implications of the current study with respect to mapping population, G x E and marker-assisted selection are discussed.