Genetic variation, phylogenetics and fruit quality characteristics of Physalis minima L. in Peninsular Malaysia

• Main Author: Usaizan, Norhanizan
• Format: Thesis
• Language: English
• Published: 2017
• Online Access: http://psasir.upm.edu.my/id/eprint/70494/1/FP%202017%2046%20IR.pdf; http://psasir.upm.edu.my/id/eprint/70494/

Physalis is a member of the Solanaceae family and it is abundantly found growing as weeds in Malaysia. This plant reported to have various antioxidants, antimicrobials and anticancer compounds such as physalin B and F which have great potential for tumors treatment. However, due to its classification as weed, little attention is given. There is a lack of information on genetic variation and phylogenetic relationship including genetics distance to the other member of Solanaceae family. A germplasm collection consisted of 130 samples representing 19 accessions from 11 states of Peninsular Malaysia was established. Physalis minima was found growing under various environmental conditions including at farm, plantation area (especially of oil palm (Elaeis guineensis)), thus proving its high adaptability to a wide variety of ecological niches in Peninsular Malaysia. The genetic diversity of the germplasm collection was estimated using 42 qualitative and quantitative morphological characteristics and eight ISSR molecular markers. Results indicate that high morphological and molecular variations existed between the 19 accessions of P. minima collected. The 19 accessions of P. minima shared similar qualitative characteristics. Results of analysis of variance revealed that there were significant differences among the accessions for all the quantitative characteristics measured. The 19 accessions collected were grouped into five diverse clusters based on their morphological characteristics using UPGMA clustering method. The dendrogram revealed that accessions 14 (B – 01) ,15 (B – 02) and 16 (B – 03) distinctly detached from other accessions. ISSRs were found to be informative molecular markers for investigating genetic diversity among the P. minima populations as indicated by the high Nei’s gene diversity coefficient and Shannon’s information index (0.28 and 0.31, respectively). Results showed that AG and CA microsatellite repeats exhibited high polymorphism. The relatively low coefficient of genetic differentiation obtained from the accessions (0.398) revealed that this plant is cross-pollinating plants. Accessions 14 (B – 01), 15 (B – 02) and 16 (B – 03) were found to be distinctly separated from all other accessions studied. The results were similar to those revealed by the cluster and PCA analyses based on morphological characteristics. Although similarity coefficients among the accessions studied obtained from morphological characteristics and molecular markers were found not to be correlated with each other, both morphological and molecular characterizations revealed that accessions 14 (B – 01) ,15 (B – 02) and 16 (B – 03) were distinctly different from the other accessions. This indicates major differences in morphology and genome composition between these populations and the other populations studied. Phylogenetic analysis was done for 13 samples from the 19 accessions by using 4 regions of cpDNA and inter transcribed spacer (ITS) region. Result indicated that, it is easier to identify P. minima from similar family member by using ITS region since cpDNA is maternally inherited and less variation occurred between sequences. However, the region rbcL on cpDNA region was able to separate P. minima from P. peruviana and other members of Solanaceae family. Phylogenetic study of P. minima by using ITS and combined ITS and cpDNA regions showed that B – 02 and B – 03, which come from accessions 15 (B – 02) and 16 (B – 03) were different from other accessions with 0.03 number of nucleotide changes with 99 to 100% of bootstrap value. Therefore, it can be concluded that these two accessions has some mutation in genomes, make them able to produce better agronomic performance. Accessions of B – 02 which has high performance and superior characteristics was further study for phytochemical profiling and effects of storage on its fruits quality. n-Hexadecanoic acid (C16H32O2) and 2- Furancarboxaldehyde, 5- (hydroxymethyl)-(C6H6O3) were major compounds that had been identified in the fruits, leaves and roots ethanolic extract with percentage of quality more than 90. Results indicated that 98% of Physalis weight loss and firmness were affected by storage duration (r2 =0.98) which were indicator of senescence. Discoloration of the fruit from greenish yellow to yellow orange occurred during storage where the value of C* and h° decreased. Storage duration longer than 6 days will increase the level of soluble solids concentration. However, the ascorbic acids, titratable acidity and pH level will decrease. Result indicated that accessions 15 (B – 02) has high level of beneficial phytocomponents and the fresh fruits can be stored up to 3 days to obtain optimum postharvest quality characteristics.