The phenotypic variability of 30 accessions of Asiatic pennywort (Centella asiatica (L.) Urb.) were collected in different regions in Thailand were evaluated. The growth habit among accessions were identified into 2 types including with 20 accessions of erect from and 10 accessions of flatten from. The leaf arrangement divided into 2 types, including with rosette (20 accessions) and spreading leaf (10 accessions). The variability of morphological and agronomical characteristics experiment was derived by Complete Randomized Design (CRD) with 5 replications. The 11 morphological and agronomical character data were collected at 2 mounts after transplant. The phylogenetic tree manifesting the diversity among 30 accessions based on Euclidean distance coefficient identified by 11 morphological and agronomical characteristics. Analysis of variance revealed high and highly significant difference among accessions for all characteristics, shown a wide range of morphological and agronomical characteristics variability of the Asiatic pennywort germplasm. The phylogenetic tree was classified Asiatic pennywort accessions into 2 different clusters with the distance coefficient ranged from 1.00 - 25.00. The 1st cluster consisted of 8 accessions and the 2nd cluster consisted of 22 accessions. The 2nd cluster was divided into 2 sub- clusters, including with sub-cluster 2.1 consisted of 21 accessions and sub-cluster 2.2 consisted of 1 accession. Mean value of the 2nd cluster was higher than the 1st group all characters except SPAD Index. The result suggested that could be used accession members in the 2nd cluster can be used for future breeding program of Asiatic pennywort in Thailand. HIGHLIGHTS The morphology and actives ingredient components of Asiatic pennywort were depended on the genetic variability and geographical conditions The variability based on morphological and agronomic characteristics of Asiatic pennywort was useful for breeding perspective The Asiatic pennywort accessions in cluster 2 could be used for breeding program in the future GRAPHICAL ABSTRACT

Germination response of nine Thai rice (Oryza sativa) cultivars was investigated under simulated acid rain at pH values of 2.5, 3.5, 4.5, 5.5 and a control at pH 6.5 using a split-plot in completely randomized design (CRD) with three replications as main plots and subplots. Germination percentage, seedling characteristics and inhibitory responses were evaluated. Results showed that rice seed germination decreased after exposure to simulated acid rain of pH 2.5, 3.5 and 4.5 compared to the control. Acid rain significantly decreased seedling root length, root-to-shoot ratio and crown roots per seedling while pH 2.5 completely inhibited all the investigated seedling characteristics. Average values of germination percentage reduction were highly significant in KDML105 and RD27 cultivars while acid rain stimulated rice seed germination in HPYTD, RD57, MLL and TTCP, suggesting that these cultivars are tolerant to acid rain stress during seed germination.