Objective Characteristics and contents of minerals in Oolong tea germplasms were studied to facilitate the classification, cultivar selection, and new variety breeding on tea plants.
Method Contents of 18 minerals in 34 Oolong tea germplasms were determined by ICP-OES, and classified using principal component and cluster analyses.
Result The average mineral contents in the specimens were found to be in the order of K＞P＞S＞Mg＞Ca＞Mn＞Al＞Fe＞Na＞Zn＞Ba＞Cu＞B＞Ti＞Ni＞Cr＞Co＞Se. The coefficients of variation ranged from 15.75% on P to 69.43% on Ti. The average genetic diversity indices varied from 1.27 on Ti to 2.21 on Zn. The contents of B, K, Mg, Mn, Na, Ni, P, S, Se, and Zn followed the normal distribution pattern, while those of Al, Ba, Ca, Co, Cr, Cu, Fe, and Ti a skew distribution, according to a W test. The correlations among these minerals were complex. The principal component analysis classified the 18 minerals into 5 groups that covered 77.40% of the total. By the cluster analysis, the 34 tea germplasms were grouped into 3 categories.
Conclusion Mainly Mn, Ca, Mg, Al, K, P and S, the mineral compositions in the 34 Oolong tea germplasms differed. Based on their varied contents, the germplasms were classified into 3 types including (a) high P, Zn and low Al, Ca, Mn, Mg, (b) high Al, Ca, Mn, Mg, K, S, and (c) low K, P, S, Zn. Five Oolong teas with high mineral accumulation capacity and nutritional value were Zhilanxiang, Benshan, Ruixiang, Tieguanyin, and Huangdan, which were considered desirable cultivars for large scale cultivation and new variety breeding as well as product development for marketing.
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