Zahoor Ahmad Swati

Carbon and nitrogen stoichiometry in Brassica napus L. seedlings after supplementation with Ca 2+ and K + under irrigated and drought stress conditions

Exposure of plants to long periods of water scarcity, mainly in arid and semi-arid regions, is one of the major reasons for over 50% reduction in average yields. Proper management of Brassica napus to enhance its ability to survive under drought and high temperature stress at early growth stages, besides development of tolerant genotypes, could improve its production in the rainfed areas. In the present study, we report the interactive effects of Ca 2+ , K + and N supplementation and water availability on the fresh biomass, N and C content, as well as C/N ratio of crop plants. Exposure to water stress significantly reduced the fresh biomass, Nitrogen (N), Carbon (C) content and the C/N ratio. Ca 2+ and K + supplementation before drought positively affected fresh biomass by stimulating N uptake and C assimilation. However, the C/N ratio was reduced after supplementation with Ca 2+ and K + . The N supplementation before drought imposition, though enhanced the N uptake, but the excessive damage to cell membranes and electrons leakage from Electron Transport Chain (ETC) during photosynthesis resulted in a decrease in C assimilation. Consequently, there was a decrease in the C/N ratio in seedlings exposed to drought after supplementation with N. Key words : Drought, nutrients supplementation, carbon, nitrogen, C/N ratio.

Fat-tailed sheep production systems in the Khyber Pakhtunkhwa Province of Pakistan.

Balkhi, Michni and Hashtnagri populations are the three fat-tailed phenotypes native to Khyber Pakhtunkhwa Province of Pakistan, harbouring the central valley. Their distribution, breeding trend and performances were evaluated through a survey using a pre-tested questionnaire during August, 2008. Out of the total populations, 70.7% were mixed flocks and 5.8%, 3.1% and 9.2% were purebred flocks belonging to Balkhi, Hashtnagri and Michni populations, respectively. Sheep flocks were reared under three different production systems, i.e. sedentary, transhumant and nomadic. Nomads keep Balkhi and are sole responsible for their development as a mutton breed. They practise autumn breeding only, for which they select the heaviest ram/s available within the community. Sedentary and transhumant shepherds had mixed flock, who were constantly replacing their native breed stock, i.e. Michni and Hashtnagri through outcrossing with Balkhi. The size of Balkhi and Michni populations warrants no immediate threat to their existence and diversity. However, in case of increased popularity of crossbreeding, Michni could pose threats of extinction. Hashtnagri on the other hand can be declared as breed at risk. Age at first lambing was significantly lower in Hashtnagri ewes, followed by Michni, crossbred and Balkhi. Hashtnagri ewes outperformed other populations in lambing twice per annum.

Microsatellite Genotyping of the Wheat Yellow Rust Pathogen Puccinia striiformis

To combat the ever-increasing threat of wheat yellow rust worldwide, understanding of the pathogen (Puccinia striiformis) population biology is indispensable. Molecular markers, particularly microsatellites, have been reported to be important tools for deciphering pathogen population structure, invasion sources, and migration history. The utility of these DNA-based markers and sequencing has been increased by the direct DNA extraction from infected leaves with subsequent multiplex-based SSR genotyping. In this chapter we describe the protocol for direct DNA extraction and its genotyping with microsatellite markers in multiplex reactions. We describe the procedure for allele scoring, and various troubles faced during microsatellite scoring and potential solutions for them.