Genetic diversity in green gram [Vigna radiata (L.)] landraces analyzed by using random amplified polymorphic DNA (RAPD)

Green gram [Vigna radiata (L.)] landraces were collected from various localities of Southern Tamil Nadu, India, to determine the extent of genetic diversity at DNA level by random amplified polymorphic DNA (RAPD) analysis using 20 decamer primers. All the primers produced polymorphic amplificationproducts with some extent of variation. A total of 200 bands were generated with an average of 10 per primer and exhibited 83.0% polymorphism. Jaccard’s similarity coefficient ranged from 0.64 to 0.93 and concentrated mostly between 0.76 to 0.93. This indicated a rather narrow genetic base of tested green gram landraces. Clustering of green gram landraces into two groups showed reasonable variability that may be exploited for selecting parents for breeding purposes. Generally distinct phenotypes identifiedusing RAPD markers could be potential sources of germplasm for green gram improvemen

Genetic diversity within and among populations of the Indian short-nosed fruit bat, Cynopterus sphinx assessed through RAPD analysis

Genetic diversity was studied among 40 different zone samples in the Indian short-nosed fruit bat, Cynopterus sphinx. Samples were collected from 127 locations in different districts of southern Tamil Nadu, India. Polymorphism at molecular level was studied by random amplified polymorphic DNA marker technique. Polymerase chain reaction (PCR) with 30 arbitrary decamer oligonucleotide primers was applied to the 40 zone samples. Out of 30 random primers screened, 22 gave reproducible polymorphic bands. PCR product of bat genome revealed a total of 234 bands, out of which 171 were found to be polymorphic. The dendrogram displaying the relative genetic similarities between the zones ranged from 0.42 to 0.92. Principal coordinates analysis revealed that the first two components accounted for 51.4% of the total variation. The results show that considerable genetic diversity was observed in this species from different zonal populations, possibly due to complete dispersal of juveniles of both sexes from their natal groups and gene flow between the zones. The results obtained from this study suggest not only a predictive framework for future studies, but also the use of genetic data in the management and meaningful conservation of this species

Bat pollination of kapok tree, Ceiba pentandra

Two species of pteropodid bats Cynopterus sphinx and Pteropus giganteus visited inflorescences of kapok trees, Ceiba pentandra through the night. A third species, Rousettus leschenaulti infrequently visited the inflorescences. Both C. sphinx and P. giganteus foraged in groups and there were temporal variations in their visits to the trees. The ventral body surfaces of the bats were covered with pollen grains when they landed on the inflorescences to lap up the nectar. In addition to bats, moths also visited the inflorescences. Bat and insectexclusion experiments were performed to study their pollination efficiency. Bats were more efficient in pollinating flowers of C. pentandra than other pollinators like insects

A preliminary study on the environmental condition of the coral reef habitat

The present investigation was carried in coral reef areas of Palk Bay, Madapam. Palk Bay corals were found disturbed by human beings due to oil pollution, waste discharge from processing units and discharge of domestic household wastes from the nearby Mandapam town. Environmental conditions of the coral reef habitat in the Palk Bay, Mandapam was analyzed for a period of six months at fortnightly intervals for March to August 2001 on the coral reef areas. Temperature, pH, Dissolved Oxygen (DO), Biological Oxygen Demand (BOD) and Total Organic Carbon (TOC) were analyzed at five different stations of Palk Bay, Madapam. The maximum mean values of temperature, pH, DO, BOD and TOC for the four experimental and control stations were 32.6°C, 8.7, 7.02ppm, 8.29ppm and 2.13% and 31.5°C, 8.3, 7.98ppm, 5.71ppm and 0.48% respectively. The sampling stations were selected on the basis of their importance