Effect of genotype by environment interaction on tea (camellia sinensis l. (o.) Kuntze) yield and quality in selected areas of Tanzania

EXTENDED ABSTRACT

The study on response of thirty-one (31) improved tea (Camellia sinensis L. (O). Kuntze) genotypes to environment variation and drip irrigation levels were conducted for tea yield and yield components. In same study, five genotypes were assessed on stability and adaptability for tea quality. A Complete Randomized Block Design with 3-replicates was adopted. Yield responses to drip irrigation were evaluated using five drip-irrigations (I0 to I4) levels. High genetic × environment interaction was evident among tea genotypes for yield and shoot density traits, implied potential to choose genotypes for these traits. Thus, new developed or introduced improved tea genotypes should be evaluated at different environments for identification of genotype specific locations. In view of locations, Ngwazi was identified most potential for yield, while Ilenge was prospective for shoot density production. Genotypes TRIT 201/43 (4) and TRIT 201/55 (8) were promising for yield in high tea performing environments. TRFK 12/19 (2), TRIT 201/47 (6), TRFK 31/8 (20) and TRFK 6/8 (30) were suitable for low yield performing environments. The genotypes exhibited above average means (x>x̅) with average response (βi≈1.0), were stable (S2 di = 0) with high reliability response (R2 i≥70%). Genotypes TRIT 201/43 (4), TRIT 201/73 (9) and TRFK 303/577 (19) were promising both for yield and shoot density at high and low performing environments. TRIT 201/16 expressed higher proportion of catechins components, while TRIT 201/43 (4) was stable and accumulated higher TC. Genotypes varied in response to drip irrigation levels, with TRFK 303/577 (19) presenting higher yield at higher drip irrigation (I4 =100%) treatment. This can be commercialized in tea areas where water for irrigation is not a constraint. Similarly, due to higher yield performance at no-drip irrigation (I0) treatment, TRIT 201/43 (4) and TRFK 303/259 (18) were considered promising under rain-fed tea depended areas. Higher shoot density and iii yield were recorded during 2014/15 and 2015/16 respectively. Yield and shoot density expressed significantly positive correlations with WUE.