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Salinity is considered as one of important physical factors influencing rice (Oryza sativa L.) production. Knowledge of salinity effects on rice seedling growth and yield components would improve management practices in fields and increase our understanding of salt tolerance mechanisms in rice. This study was designed to assess the role of Saltol QTL in regards to effects of salinity on plant growth and yield components of different genotypes of rice at different growth stages. A greenhouse study was conducted to evaluate the response of 30 rice genotypes to three levels of salt stresses (0, 60, 100 mM NaCl) at reproductive stage. The seedling stage response of these genotypes to salinity with electrical conductivity at 12 dSm-1 also investigated. Pollen viability, number of unfilled and filled grain and grain yield per plant were evaluated. The rice genotypes differed significantly for salt tolerance at seedling stage. The genotypes were also significantly varied for the traits measured at the reproductive stage. The interactions of genotypes x salinity treatments were significant for pollen viability, number of unfilled grain and grain yield. Grain yield reduction due to salinity was more sever for control to 60mM than for 60mM to 100mM. Pollen viability was found to be a robust criterion to screen the genotypes for salt tolerance at the reproductive stage. Pokkali cultivar possessing a major quantitative trait locus (QTL) for salt tolerance at seedling stage (Saltol) mapped on chromosome 1 was used as reference for haplotyping. Thirty rice genotypes divided into 16 different haplotypes based on Saltol QTL. RM8094 and RM10745 microsatelite markers found to be the most effective markers for discriminating the salinity tolerant genotypes. [ABSTRACT FROM AUTHOR]

Buffalopox virus (BPXV) is considered to be a close variant of vaccinia virus (VACV), the prototype member of the genus Orthopoxvirus. In the present study, we have analyzed the sequences of H3L, A27L, and D8L gene-homologues of VACV in BPXV to elucidate its genetic relationship to VACV and other orthopoxviruses (OPVs). Products of these genes have been shown to be important in attachment of VACV to host cell surface receptors during viral entry. Additionally, the A27L gene is also responsible for cell fusion during infection, while the H3L gene is required for synthesis of the highly immunogenic major envelope protein p35. Full-length nucleotide sequences of H3L, A27L, and D8L genes of three BPXV isolates were determined by PCR amplification, cloning, and sequencing. The nucleotide (nt) sequence and the deduced amino acid (aa) sequences were compared with published sequences from other members of the genus Orthopoxvirus. Comparative sequence analysis of all the three genes revealed high sequence identity of BPXV isolates with VACV (close to 99% sequence identity) at both the nt and aa level. Phylogenetic analysis based on the deduced aa sequences of the H3L, A27L, and D8L genes also showed that BPXVs are more closely related to VACV than to any of the other OPVs. [ABSTRACT FROM AUTHOR]