Genetic diversity and population genetic structure of the wild rice species Oryza rufipogon and O. nivara in Sri Lanka were studied using 33 microsatellite markers. A total of 315 individuals of 11 natural populations collected from the wet, intermediate, and dry zones of the country were used in the study. We found a moderate to high level of genetic diversity at the population level, with the polymorphic loci (P) ranging from 60.6% to 100% (average 81.8%) and the expected heterozygosity (H E) varying from 0.294 to 0.481 (average 0.369). A significant genetic differentiation between species and strong genetic structure within species were also observed. Based on species distribution modeling, we detected the dynamics of the preferred habitats for the two species in Sri Lanka and demonstrated that both O. rufipogon and O. nivara populations have expanded substantially since the last internal glacial. In addition, we showed that the geographical distribution of the two species corresponded to the climate zones and identified a few of key environmental variables that contribute to the distribution of the two species, implying the potential mechanism for ecological adaptation of these two species in Sri Lanka. These studies provided important insights into the population genetics and evolution of these wild species in Sri Lanka and are of great significance to the in situ conservation and utilization of these wild resources in genetic improvement of rice.

The study assessed the variations in morphologically, physiologically and anatomically distinct traits of wild rice species in Sri Lanka; O. nivara, O. rufipogon, O. eichingeri, O. rhizomatis and O. granulata, which could be useful in rice breeding. The wild rice species were grown in a common garden, and the morphological traits were measured soon after heading. The results showed qualitative parameters such as the panicle type, awning, stigma colour, lemma and palea pubescence, seed coat colour, blade pubescence and ligule shape, are distinctive among the five species and are promising characters in their field identification. ANOVA revealed that the quantitative traits, such as flag leaf length, flag leaf width, culm length, culm diameter, panicle length, 100 grain weight and plant height are useful for further confirmation of species. The highest net photosynthetic rate (5.86 µmol m -2 s -1 ), high cluster width of the base (61.4 µm), and trichome density (184.33 per 25 mm 2 area) were observed in O. rufipogon compared to the rest, and such desirable traits are effective in rice breeding. Moreover, transpiration rates, stomatal conductance and substomatal CO 2 concentration are ideal physiological traits to be considered in super rice breeding. Significant correlations were observed between transpiration and photosynthesis processes. Thus, our study provides a clear picture on habitat preferences, life cycle, distinctive morphologies and diverse functional traits to be effectively used in field identification and future utilisation of wild relatives of rice in the plant breeding programmes.

Wild species of rice (Oryza) have superior agronomic characteristics to be incorporated in rice breeding programs worldwide.  Population studies of wild relatives of rice in Sri Lanka has not being well documented despite a few of attempts. In the present study, phenotypic diversity of Oryza rufipogon populations exist in Sri Lanka were characterized based on nine quantitative morphological traits. Populations (P1, P2, P3, P4 and P5) were established in a common-garden and were characterized. The results revealed moderate phenotypic diversity among O. rufipogon populations studied. However, flag leaf length and awn length were the most variable traits while plant height, flag leaf angle, flag leaf panicle neck length and spikelet angle were the least variable traits. O. rufipogon can be simply distinguished using flag leaf length and width, panicle branching type and distance from panicle base to lowest spikelet insertion. The dendrogram results indicated that four main clusters are at a similarity level of 98.73, showing the diversely related populations with a high identity based on higher similarity values. P1 and P2 populations grouped together by forming the first cluster. The second, third and fourth clusters consisted of P3, P5 and P4 populations, respectively. One population from first cluster and P3, P5 and P4 populations can be used for conservation. This study highlights the phenotypic diversity of O. rufipogon populations existing in Sri Lanka across the geographic locations and Knowledge on such morphological diversity provides opportunities to design conservation strategies and the potentials of using particular population based on breeding objectives.

Information on the genetic diversity of wild rice species in Sri Lanka is relatively meagre, though it plays a key role in crop improvement programs of cultivated rice (Oryza sativa L.). The present study was carried out to identify the morphological variation pattern of the wild populations of O. nivara in Sri Lanka. Seven populations (P1 to P7) collected from different agro-ecological regions were characterized in a common garden based on nine morphological traits. The findings revealed a high level of phenotypic variation between populations when compared to within a population. The most variable traits were the flag leaf panicle neck length (FLPNL) and flag leaf angle (FLA), whereas the least variable trait was the flag leaf length (FLL). Box plots clearly illustrated the large differentiation of phenotypic traits in the entire distribution of wild rice populations. The cumulative values of the two principal components, i.e., FLPNL and FLA, explained 58.7% of the total variance. Populations from similar natural habitats clustered together. The P7 was adapted to intercept more sunlight by increasing flag leaf width (FLW) and FLA to compete with weeds and other shrubs. P2 and P5 were the most closely related populations representing approximately similar ecological conditions of the dry zone. The P3 population from the intermediate zone showed a vigorous plant growth with the highest plant height, culm girth and awn length (P < 0.05). Knowledge of such morphological diversity would facilitate designing conservation strategies and basic information for the proper utilization of wild resources in rice genetic improvement.

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Recently, Moringa leaves substituted string hopper flour has been introduced to the market with regards to renewed consumer trend of healthy eating. However, the way consumer behaves towards this newly introduced product is questionable and hence it needs to be researched. Therefore, this study is mainly focused on evaluation of the consumer attitudes and acceptance of Moringa added string hopper flour. Study was consisted of a survey to evaluate the consumer attitudes. Moreover, a sensory evaluation was carried out to assess the sensory performance of the particular product. Collected data were mainly analyzed by using     SPSS version 16. Interestingly, results showed that potential health benefits of Moringa remained prominent in the acceptance of the product. Further, sensory results showed appreciable sensory performance allowing consumers to purchase the product with sensorial intention. All the respondents (100%) were in satisfactory level regarding the product. Study demonstrates requirement of popularizing and elevating the availability of the product to achieve better market opportunities in order to widening the market Current study confirmed that the product exhibits potential of appreciable commercial acceptance and substantial purchasing capacity.

Shot whole borer (Xyleborusfornicatus Eichh.) (SHB) is considered as the most serious and economically important pest in tea plantations in Sri Lanka. Present study was done to determine the parameters for screening of different tea cultivars against SHB. Prune time assessments on plant growth parameters of plant breeding trials were used to correlate data on galleries per 30cm in the laboratory bioassay to determine their relationship on SHB infestation in tea. A set of new tea cultivars with known tolerant and susceptible cultivars were used in the study. The regression analysis indicated that the intermodal length, mean number of prune cuts and mean prune weight had a significant positive relationship (P<0.05) with SHB infestation and those could be considered as valid parameters for cultivar screening against SHB in tea. Formulated multiple regression model [ 30cm units= (−8.27)+(0.1183 1)+(1.987 2), where; X1-mean number of prune cuts, X2-internodal length], was significant (P=0.007) and it explained 56.05% variation of galleries per 30cm (R2=56.05%). Mean number of galleries per 10cm stem had a significant (P<0.05) positive relationship (0.65) and the model explained 41.62% variation of galleries per foot (R2=41.62%).

Weedy rice (Oryza sativa f. spontanea) is a conspecific weed that has invaded cultivated rice fields, effectively adapted to modern management practices, leading to substantial yield losses and reduced harvest quality. The understanding of weedy rice genetic diversity and population structure is critical in developing effective control measures. Twenty weedy rice populations were collected around the island and evaluated using 33 SSR markers. Our findings indicated that the genetic diversity (He) in a population of weedy rice was reasonably high (0.305 - 0.560). A high level of within-population (79%) and a low level of among-population (21%) genetic variation were found by analysis of molecular variance (AMOVA). There is no significant correlation across genetic and geographical distances (P>0.05). The unweighted pair group method with arithmetic mean (UPGMA) demonstrated that 20 populations were structured into two well-separated groups. Remarkably, many admixed individuals were evident according to the STRUCTURE. Weedy rice management strategies should focus on micromorphological monitoring to detect, group, and eliminate weedy rice in paddy fields, restricting the exchange of saved paddy seeds among geographical regions, increasing the production and distribution of certified seeds, the varietal recommendation for rice-growing regions to minimize mixing of varieties with different age classes, raising awareness are the recommendations to reduce the emergence of future weeds.