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The family Solanaceae is immensely important because it has many species with food and medicinal values. There are nine major Solanaceous spp. Namely S. Melongena L. (Wambatu and Elabatu), S. virginianum L. (Katuwelbatu), S. torvum Sw. (Thibbatu), S. violaceum Ortega (Thiththathibbatu), S. trilobatum L. (Welthibbatu), S. hispidum Pers. (Gonabatu), S. pubescens Willd. (Walthibbatu), S. nigrum sensu Trimen (Small Kalukenweriya) and Datura stramonium L. (Sudu aththana) collected from Uva Province, Sri Lanka, a prominent area of growing these species. Currently these species are underutilized in spite of their medicinal importance. No detailed morphogenetic and medicinal level characterization of these species has been reported to promote their economic use. Therefore, the present study was conducted to assess the morphogenetic diversity and the antibacterial activity of these Solanaceous spp. The plant height, canopy width and leaf and fruit morphology were highly variable among these species. DNA barcoding using locus matK revealed a total of eight haplotypes. The polymorphism in matK locus is not diverse enough to set the species limit of the genotypes within S. melongena and to distinguish Thiththathibbatu from Walthibbatu. The antibacterial activity assay using ethanol extracts of roots demonstrated that all these species have inhibitory activity against Gram positive Staphylococcus aureus (NCTC4838) and Gram negative Escherichia coli (JM109).

Phosphorous deficiency (PD) tolerance is a polygenic trait. The underlying genetics of PD tolerance trait is important to provide the basis for detecting Quantitative Trait Loci (QTLs) and validating markers that could be used in Marker Assisted Breeding (MAB) in rice. The PD tolerance of Sri Lankan rice germplasm has been characterized. However, no attempts were taken to develop and validate the DNA markers for the breeding purposes and to understand the genetic basis of the traits. The present research project was conducted to assess the PD related traits and to validate internationally published DNA markers that are linked to PD tolerance using Sri Lankan rice cultivars. A total of 84 crosses were made and advanced to F2 and higher generations. Out of these crosses, an important subset of three crosses was selected based on the overall PD tolerance and sensitivity, importance as mega production varieties and pedigree connections between the cultivars. The plant height, number of tillers, shoot dry weight, leaf width, flag leaf width and the color metrics L*, a*, b*, hue (h*) and chroma (C*) were measured from 200 individuals each from the three populations grown under P deficient (Po) soil conditions. Except color traits, other traits were normally distributed and exhibited higher broad sensitivity. The color metrics indicate the presence of possible epistatic interactions between the major underlying loci. From each population, two extreme bulks were selected from the highest and lowest ends of shoot dry weight (SDW) for bulk segregant analyses (BSA) to validate the DNA markers for PD tolerance. It was observed that, DNA marker K46-K1 can be used for MAB of rice for PD tolerance. The genetic information generated in the present study can also be used for larger scale genomic studies such as SNPs, GBS and GWAS mapping.

Phosphorus (P) deficiency in soil is a major constrain for rice production. An important set of rice genotypes (landraces, old improved and new improved varieties) were screened for P deficiency tolerance in two major cropping seasons of Sri Lanka, in 2012. The Ultisol soil, which was collected from a plot cultivated with rice without fertilizer application for past 40 years (P0) at the Rice Research and Development Institute (RRDI), Bathalagoda, Sri Lanka, was used as the potting medium for greenhouse trials. Two field trials were conducted in the same plots at RRDI. Both P0 and P30 (30mg/kg P2O5) conditions were used in the two greenhouse trials. At the early vegetative (three weeks after transplanting), late vegetative (six weeks after transplanting) and flowering stages, plant height and number of tillers per plant were recorded. At the flowering stage, shoots were harvested and shoot dry weight, shoot P concentration, shoot P uptake and P utilization efficiency were measured. All data were statistically analyzed using analysis of variance, regression and cluster procedures. The measured parameters were significantly different between P0 and P30 conditions (P < 0.05). Higher shoot dry weight was reported by the rice genotypes H4 and Marss under P0 conditions. The regression analysis between shoot dry weight and P utilization efficiency revealed that the studied rice genotypes could be categorized to three P deficiency tolerance classes. A total of 13 genotypes could be considered as highly tolerant and 4 genotypes as sensitive for P deficiency. These results could be used to select parental genotypes for breeding and genetic studies and also to select interesting varieties or landraces for organic rice production.

Phosphorous deficiency (PD) tolerance is a pivotal trait that is advantageous if present in modern day high performing rice varieties. However most of the frequently grown mega rice varieties lack this trait leading to expensive application of artificial phosphate fertilizer results secondary consequences such as environmental pollution and higher cost of production. Marker assisted breeding (MAB) for PD tolerance in rice is often hailed as the pragmatic solution to tackle this problem. The genetic basis of PD tolerance in rice has been dissected using a wide cross made between PD tolerant rice landrace Kasalath and a sensitive landrace Nipponbare . A major QTL known as Pup1 has been identified, molecularly characterized and underlying polymorphisms were detected. A major INDEL region within Pup1 QTL within Kasalath background is conferred to control the PD tolerance which is genetically ‘null’ in Nipponbare background. The DNA marker K46 which is present within Pup1 has been developed to identify this INDEL region in Kasalath like genotypes. The PD tolerance in Sri Lankan rice germplasm has been recently studied using a core panel of rice genotypes that are important in rice breeding programs. It is important to figure out the genomic landscape of the INDEL region of Pup1 QTL in these Sri Lankan rice genotypes. Therefore the present study was conducted to characterize the K46 DNA marker locus of the previously characterized for PD tolerance rice cultivars in Sri Lanka. The K46 specific primer-pair was assayed across 30 selected Sri Lankan cultivars and the PCR products were sequenced. The resulted DNA sequences were aligned with the Kasalath reference sequence for K46 locus. Further cluster analysis of the identified SNPs resulted four distinct haplotypes in which nine cultivars were grouped with Kasalath like haplotype, two unique haplotypes and the null haplotype. However, there is no strong association between the haploype class and the PD tolerance score of the cultivars implying the potentially novel PD tolerance mechanisms that require further studies.

Black pepper (Piper nigrum L.) is an important spice. The adulteration of black pepper seeds and powder with papaya seeds, green chili and red chili can be seen and limited studies have been conducted to detect these adulterants. The objectives of the present study were to assess the appropriateness of morphometric methods to discriminate papaya seed and chili adulterations in black pepper and to establish a DNA based strategy to detect these adulterations. A necessary adulteration series of seeds and powders were prepared for the analyses along with commercial samples. The appearance of the seed and powder samples were slightly different but not very distinct among the pure and adulterated samples emphasizing the need of a biochemical approach to detect the adulteration. The adulterated and commercial black pepper samples received lower pungency ranks compared to that of pure samples. QIAGEN DNeasy® Plant Mini Kit was successful in extracting PCR amplifiable DNA from any sample without papaya seeds and the modified CTAB method was able to extract required PCR amenable DNA from any sample with papaya seed material. The universal DNA barcoding primer pair, psbA-trnH, was used to amplify the DNA. Black pepper DNA yielded 200 bp band, chili and papaya DNA yielded 450 bp band and DNA from adulterated samples produced both 200 bp and 450 bp bands. Therefore this strategy can be used to detect papaya / chili adulterations in black pepper.

Sweet orange (Citrus sinensis), a key fruit species, is considered as a primary ingredient in herbal medical formulations against ailments such as food borne diseases. Sour orange (C. aurantium) is also very famous as a medicinal plant. There are six commonly grown sweet orange cultivars in Sri Lanka (Arogya, Bibila sweet, MKD, Sisila, BAN and MT) but the antibacterial activity present in their fruit juice is not well documented. Therefore, the present study was conducted to characterize the antibacterial activity of the fruit juice of these sweet oranges in comparison to sour orange and also to establish DNA barcodes for the tested cultivars for precise identification. Fruit juice was collected from sweet orange cultivars and sour orange and antibacterial activity was measured against three model pathogenic bacterial species, Escherichia coli, Staphylococcus aureus and methicillin-resistant S. aureus. After employing filter paper disc method, the diameter of zone of bacterial inhibition (DZI) was measured as the parameter of antibacterial activity. The genomic DNA was extracted from all the tested plants and PCR amplified using trnH–psbA primer pair and subjected to DNA sequencing, followed by alignment analysis and dendrogram construction. Arogya and MKD did not show any antibacterial activity (DZI = 0.0 mm), whereas Sisila, BAN and MT showed antibacterial activity only against E. coli and S. aureus (mean DZI of 8.2 mm and 8.4 mm respectively). Bibila sweet and sour orange showed significantly higher antibacterial activity against all E. coli, S. aureus and methicillin-resistant S. aureus (mean DZI of 10.2 mm, 10.5 mm and 7.8 mm respectively). DNA barcoding provided unique sequence identifiers for each cultivar. These antibacterial activity data in combination with DNA barcodes could help to develop new cultivars through breeding to promote the sweet orange industry in Sri Lanka.The Journal of Agricultural Sciences, vol.11, No 1, January 2016, pp.13-23

Chili pepper ( Capsicum spp.) is important as a spice, flavour enhancer, vegetable and component in herbal medicine. The numerous phytochemicals and their medicinally important properties present in diverse germplasm of chili pepper have been characterized and documented. Capsaicinoids, carotenoids, vitamins, flavonoids such as anthocyanins are present as the major phytochemicals in chili pepper fruits. Capsaicinoids, pungent analogues of capsinoids, are the most important group of phytochemicals in which capsaicin and dihydrocapsaic in are prominent in providing the basis for pungency and medicinal properties. The detailed studies conducted on the phytochemicals in chili pepper fruits using mouse models and human cell lines have reported an array of anticancer effects on leukemia, myeloma and various carcinomas associated with the digestive tract. In addition, chili pepper possesses anti-inflammatory, antidiabetic, antimicrobial, anticholesteremic, anticlotting and antioxidant activities. Therefore, this review is compiled to provide a comprehensive assessment of the phytochemical profile and medicinal values of chili pepper. Collectively, numerous studies performed to date demonstrated the potential medicinal significance of chili pepper for development of herbal medicine and to plan further studies to elucidate other hitherto unknown medicinal values.