Random Amplified Polymorphic DNA (RAPD) assay was conducted for molecular genetic analysis of six cowpea (Vigna unguiculata L. Walp germplasms) i.e. BARI Cowpea, BARI Felon-1, Ranirhat, Ruma, BF06001 and BF060011, to observed genetic variability and relatedness among them. Out of 15 decamer random primers, three were used to amplify genomic DNA and the primers yielded a total of 20 RAPD markers of which 11 were considered as polymorphic. The maximum number of bands (9) (25%) produced by the primer S1184, whereas the least number of bands (5) (15%) was generated by the primer OPA10. The average scorable and polymorphic bands produced by the three primers were 6.67, and 3.67, respectively. The percentage of polymorphic loci was 55. The UPGMA dendrogram based on Nei's (1972) genetic distance between different pairs were correlated with their sources of origin. The dendrogram indicated segregation of six germplasms of cowpea into two main clusters; the main clusters are further divided into sub clusters. In sub cluster I, BARI Cowpwa-1, Ranirhat and Ruma formed sub sub-cluster I; BARI Felon-1 formed alone sub sub-cluster II. Again, sub sub-cluster I; Ruma formed alone cluster and BARI Cowpea-1 and Ranirhat formed sub sub-cluster III.

An experiment was conducted to investigate the effect of irrigation water management practices and rice cultivars (BRRI Dhan -28 and BINA Dhan -8) on methane (CH4) emission and rice productivity during Boro season (January to May 2011) at the experimental field o6f Department of Environmental Science, Bangladesh Agricultural University, Mymensingh . Two different rice varities such as BRRI Dhan-28 and BINA Dhan-8 was selected for the study. Different water management practices such as Continuous flooding (CF) at 5 cm standing water, CF at 5cm standing water for first 3 weeks, CF at 5cm standing water for first 6 weeks, CF at 5cm standing water for first 9 weeks, alternate wetting and drying(irrigated at 5cm depth, 3 day in a week and 4 days drying) and water saturated condition (no standing water) were followed in the different plot in this experiment. It was observed that alternate wetting and drying (irrigated at 5cm depth, 3 day in a week and 4 days drying) treatment gave highest yield 5.76 t/ha and 6.713 t/ha respectively in BRRI Dhan-28 and BINA Dhan-8. However the lowest seasonal methane emission 13.349 g CH4/m2/season (26.37% less than CF at 5 cm standing water) and 13.808 g CH4/m2/season (28.08% less than CF at 5 cm standing water) were found under the alternate wetting and drying in BRRI Dhan-28 and BINA Dhan-8 respectively. So alternate wetting and drying(irrigated at 5cm depth, 3 day in a week and 4 days drying) irrigation water management practice should be followed for reducing CH4 emission and sustaining rice productivity during the Boro season in Bangladesh climatic condition.