ABSTRACT

The thesis “Assessment of the genetic diversity of black pepper cultivars (Piper nigrum L.) commonly planted in three main cultivated areas of the Southern provinces based on morphological characteristics” was conducted from May 2008 to August 2009. Eighteen black pepper cultivars commonly grown in principal production areas representing for three agro-ecological regions: the Southeastern Region (Dong Nai and Ba Ria - Vung Tau provinces), the Central Highlands (Dak Nong and Gia Lai provinces), and the Southern Central Coastal Region (Phu Yen province) were examined. Morphological characteristics of black pepper cultivars were recorded based on descriptors for black pepper developed by the International Plant Genetic Resources Institute (IPGRI, 1995). Recorded data were standardized to do the hierarchical cluster analysis with UPGMA method based on Euclidean distance coefficients of 28 different morphological traits (qualitative and quantitative ones) from 18 cultivars with NTSYS-pc 2.1 software.

The thesis results are as follows:

- Morphological characteristics (qualitative and quantitative traits) of 18 black pepper cultivars commonly planted in the Southern provinces are rather diversified.

- Couples of black pepper cultivars Ando1 and (Vinh Linh 1, Se Phu Quoc, and Ando4); Se Phu Quoc and (Ando3 and Ando4) are genetically different based on morphological characteristics.

- Four groups are clustered from 18 black pepper cultivars at Euclidean distance coefficient value 7.84 of the UPGMA cluster dendrogram. Group I includes all 13 cultivars with six Vinh Linh, six Se and Ando4 cultivars; in which group I are divided into three sub-groups at value 6.67 of Euclidean distance coefficient, group IA with only one cultivar (Vinh Linh 1), group IB with one cultivar (Ando4), and 11 remains belong to group IC (five Vinh Linh and six Se cultivars). Group II consists of two cultivars (Trau 1 and Trau 2). Group III composes of two cultivars (Ando1 and Ando3) and Group IV comprises only one cultivar (Ando2).

- Subgroup IB (Ando4) and subgroup IC3 (Vinh Linh 2, Vinh Linh 3, Vinh Linh 4, Vinh Linh 6, Se Loc Ninh and Se Phu Quoc) has better agronomic characters than the others, gave also rather high yield (over 3 kg of dry fruit/vine). In which three cultivars, namely Se Loc Ninh, Se Phu Quoc and Ando4, gave a rather high and stable productivity with fairly good berries.