Morphological and Bitterness Level Characterization of Phyllanthus emblica Drupes Reveals Higher Diversity

Abstract

Phyllanthus emblica L. (V. Nelli) is an important constituent of indigenous medicine and acommercially important fresh fruit species. The diversity of the P. emblica germplasm in SriLanka has not been studied in detail according to our knowledge. Therefore, the present studywas conducted to characterize the drupes of P. emblica gremplasm in Sri Lanka.

A total of 475 P. emblica drupes harvested from 66 trees in selected areas of Anuradhapura,Kandy and Kurunegala districts of Sri Lanka. For each drupe, seven morphometric data;drupe height, width, weigh, mesocarp thickness, stone width, height and weight weremeasured. Also 61 drupes were used for the quantitative analysis of the epicarp colour ofdrupes using a colourimeter. An organoleptic property; bitterness was analysed in relation todrupe size by having a taste panel of independent human subjects. The data were analysedusing parametric and non parametric statistical methods.

The cluster analysis based on drupe size traits clearly characterized the P. emblica germplasmin to four clusters. The means of drupe weight (Cluster 1; 5.98 g, Cluster 2; 3.59 g, Cluster 3;2.13 g, Cluster 4; 14.21 g) were significantly different (P<0.05) among the four clusters.There were significant differences in colour metrics between small and large drupe groups.The results indicated that the smaller drupes (chroma; 21.64, hue angle; -10.86) are lighter,yellowish, sharper and less colourful (i.e. dull) than that of the larger drupes (chroma; 12.66,hue angle; -21.11). The sensory data analysis revealed that generally smaller drupes arebitterer (57% of drupes awfully bitter) in contrast to larger drupes (47% of the drupes mildlybitter) but there is no guarantee that small drupes are always bitter. The Crarmer’s Vcoefficient (0.47) indicated that the association between drupe size and the bitterness has noperfect linear relationship (Crarmer’s V coefficient is 1.00 for such a linear perfectrelationship). The drupe traits were not different with respect to their tree locations or theclimate and the environmental factors contributed less than other factors such as genetics.The P. emblica germplasm has a higher diversity in Sri Lanka and should be conserved inorder to maintain the genetic stochasticity. It sets the foundation to implement conservationmeasures and this diversity structure can be further verified by molecular portrayal which iscurrently undertaken by our research group. The proposed characterization can be used as aguideline to define a working level core-collection that will be useful in taking decisions forgermplasm conservation and in planning crop improvement programs of P. emblica.