Molecular Characterization and Population Genetic Structure of Fagopyrum Species Cultivated in Himalayan Regions

Fagopyrum spp. (buckwheat) is a dicotyledonous pseudocereal crop mainly cultivated in the north-western Himalayan regions for its highly nutritional, antioxidant and therapeutic values. In the present investigation, molecular characterization was performed by using ISSR (inter simple sequence repeat) markers on 42 accessions of four buckwheat species (Fagopyrum esculentum, F. sagittatum, F. tataricum and F. kashmirianum). The 12 pre-screened ISSR primers amplified 102 bands, and amongst them 85 bands exhibited polymorphism with an average polymorphism of 82.73%. The results revealed that Shannon’s information indices (I) and Nei’s genetic diversity (H) were low for F. tataricum (I = 0.1028 ± 0.2307; H = 0.0707 ± 0.1617) and high for F. esculentum (I = 0.1715 ± 0.2622; H = 0.1164 ± 0.1796). It was estimated that within the accessions of Fagopyrum species, the species diversity (HT) and mean diversity (HS) were 0.3200 and 0.1041, respectively. Molecular variance partitioning by AMOVA also indicated a significant genetic differentiation accounting for 73% among and 27% within the accessions of Fagopyrum species. Overall, accessions of F. esculentum had the greatest distance from the other accessions of buckwheat species, which includes F. sagittatum, F. tataricum and F. kashmirianum as revealed by FST distance and Nei’s unbiased genetic distance. The dendograms based on UPGMA and PCoA segregated 42 accessions of four buckwheat species into three major groups. This study clearly reveals a considerable amount of genetic diversity at the intra-specific level in F. esculentum, F. sagittatum and F. kashmirianum accessions. The factors responsible for it are diverse geographical conditions, pollinating behavior and cultivation practices adapted in these regions. The study also indicated a close phylogenetic relationship between F. tataricum and F. kashmirianum.

UNUSUAL TYPES OF LAYERED ORGANIC CRYSTAL HYDRATES

In molecular crystalline hydrates with a high content of crystallization water infinite H2O...OH2 nets or finite fragments of such nets are formed. As a rule, these nets contain 5- and 6-membered cycles (H2O)n. Brand new topological types of layered organic crystal hydrates among the structures included in the Cambridge Structural Database in 2009–2019 were found and investigated. The discovered nets were deposited to the Topological Types Database. Topological characteristics of new nets are described, in particular, the maximum possible symmetry, information indices, vertex, edge and face transitivity of the nets

A new approach to measuring absolute pitch on a psychometric theory of isolated pitch perception: Is it disentangling specific groups or capturing a continuous ability?

Absolute Pitch (AP) is commonly defined as a rare ability that allows an individual to identify any pitch by name. Most researchers use classificatory tests for AP which tracks the number of isolated correct answers. However, each researcher chooses their own procedure for what should be considered correct or incorrect in measuring this ability. Consequently, it is impossible to evaluate comparatively how the stimuli and criteria classify individuals in the same way. We thus adopted a psychometric perspective, approaching AP as a latent trait. Via the Latent Variable Model, we evaluated the consistency and validity for a measure to test for AP ability. A total of 783 undergraduate music students participated in the test. The test battery comprised 10 isolated pitches. All collected data were analyzed with two different rating criteria (perfect and imperfect) under three Latent Variable Model approaches: continuous (Item Response Theory with two and three parameters), categorical (Latent Class Analysis), and the Hybrid model. According to model fit information indices, the perfect approach (only exact pitch responses as correct) measurement model had a better fit under the trait (continuous) specification. This contradicts the usual assumption of a division between AP and non-AP possessors. Alternatively, the categorical solution for the two classes demonstrated the best solution for the imperfect approach (exact pitch responses and semitone deviations considered as correct).

SANITARY AND HYGIENIC ASSESSMENT OF WATER QUALITY IN THE DEVITSA RIVER OF THE UPPER DON BASIN BY THE PERIPHITON COMMUNITY OF ARTIFICIAL SUBSTRATES

We reviewed the issues of sanitary-hygienic assessment of water quality in the Devitsa River according to the indicators of periphyton of artificial substrates. The annually increasing level of water pollution requires the improvement of social and hygienic monitoring system. The issues of monitoring water bodies in the Voronezh Region is particularly relevant in the summer season, when rivers are used by the population for recreational purposes. To ensure the population safety, it is necessary to assess water by sanitary and hygienic indicators. Such assessment is carried out on the basis of the Hygienic and Epidemiological Center in the Voronezh Region, however, if sampling is carried out quite often and at different points for large and medium-sized rivers, that the limitation of sampling points and the total number of samples for small rivers does not allow for an objective determination of water quality and fully guarantee its compliance with sanitary and hygienic requirements. The solution to this problem can be the use of biological control as an additional method of monitoring, which allows to assess the ecological and sanitary-hygienic water quality in the river with the greatest accuracy along with hydrochemical control. As a bioindicator of the pollution level of a reservoir, both individual taxa and communities and separate groups of hydrobionts can be used. Benthic organisms are most often used as bioindicators of the level of water pollution in rivers, but many authors consider it more appropriate to use the periphyton organisms. This is due to the fact that benthic organisms, being under the influence of bottom sediments, are more tolerant to pollution, while periphyton reflects water quality more adequately. The study of the periphyton of the reservoir allows the calculation of information indices reflecting the water condition. The application of the bioindication method makes it possible to identify periods when more frequent sampling is required to establish the compliance of river water with sanitary and hygienic standards.

Assessment of genetic diversity of different tomato genotypes using RAPD markers

The present investigation was carried out for assessment of genetic diversity among the 28 tomato genotypes though three random amplified polymorphic DNA (RAPD) markers. A total of 15 distinct DNA fragments ranging form 100-1000 bp were amplified by using three selected primers of which 5.00 polymorphic bands per primer and over all polymorphic loci was 100 percent. The extent of genetic diversity among these genotypes was computed through parameters of genetic diversity and Shanon’s information indices. The highest genetic distance was observed among the accession Cl-3d-0-99 (V93) vs. F1 (G X V12), F1 (G X V17), F1 (G X V29) and Durch fuegel (G) vs. F1 (G X V17) and F1 (G X V93) vs. F1 (G X V12), F1 (G X V17), while the lowest genetic distance was observed among the accessions Fut. Wed Abrid (V94) vs. Sunlight pole (V67) and F1 (V67 X VG) vs. F1 (V17 X VG), F1 (V93 X VG) and F1 (V93 X V17) vs. F1 (V17 X VG), F1 (V67 X VG), F1 (V93 X VG). The Unweighted Pair Group Method of Arithmetic Mean (UPGMA) dendrogram based on Nei’s genetic distance divided the genotypes into two main clusters: A & B. Cluster ‘A’ consists of 19 accessions and cluster ‘B’ consists of 9 accessions. The information generated from this study could be useful in gene mapping and marker assisted breeding for future tomato breeding programs. Progressive Agriculture 29 (4): 276-283, 2018

Model Selection for Multilevel Mixture Rasch Models

Mixture item response theory (MixIRT) models can sometimes be used to model the heterogeneity among the individuals from different subpopulations, but these models do not account for the multilevel structure that is common in educational and psychological data. Multilevel extensions of the MixIRT models have been proposed to address this shortcoming. Successful applications of multilevel MixIRT models depend in part on detection of the best fitting model. In this study, performance of information indices, Akaike information criterion (AIC), Bayesian information criterion (BIC), consistent Akaike information criterion (CAIC), and sample-size adjusted Bayesian information criterion (SABIC), were compared for use in model selection with a two-level mixture Rasch model in the context of a real data example and a simulation study. Level 1 consisted of students and Level 2 consisted of schools. The performances of the model selection criteria under different sample sizes were investigated in a simulation study. Total sample size (number of students) and Level 2 sample size (number of schools) were studied for calculation of information criterion indices to examine the performance of these fit indices. Simulation study results indicated that CAIC and BIC performed better than the other indices at detection of the true (i.e., generating) model. Furthermore, information indices based on total sample size yielded more accurate detections than indices at Level 2.