Meta-Analysis (MA) is one of the emerging and advanced methodology for quantitatively reviewing literatures for research that provides a wider picture of a research problem. The methodology combines secondary data from various primary studies and estimates the overall effect of an intervention or treatment. Though, it was first used in the field of medical sciences and psychology, its application has become wider and common even in agricultural sciences, especially economics and extension. MA helps in estimating the impact of an intervention by taking two different groups for comparison viz., Control and Treatment. Researchers frame certain criteria (Inclusion-Exclusion) in order to decide the studies to be included or excluded for analysis. Once the number of studies to be included are finalized, the analysed data from these studies are pooled and analysed again through various Meta-Analytical methods. These methods include Basic MA and Advanced MA which involves calculation of effect sizes, heterogeneity tests, moderator and sensitivity analysis and publication bias assessment. The inference of an MA can be derived from the overall effect sizes (estimates of MA) which indicates the amount of effect or impact an intervention has on the sample. Therefore, MA by aggregating data from various primary studies is said to have higher statistical power and hence reveals increasing prominence in social sciences as well as in efficient policy making process.
Nitroplast is a recently discovered eukaryotic organelle that functions in nitrogen-fixation. The first report of nitroplast was from the marine algae Braarudosphaera bigelowii, in which the endosymbiotic relationship of a nitrogen-fixing cyanobacteria evolved into an organelle. Like other organelles, during the course of evolution, the genome of the endosymbiotic organism lost many important genes and hence it cannot exist independently. As the B. bigelowii genome encodes most of the proteins required for the nitroplast, it is now regarded as an organelle. Engineering nitroplast enables autotrophic nitrogen fixation in crop plants, which in turn reduces the usage of chemical fertilizers, thereby leading to sustainable agricultural practices.
A mapping population can be used to map genetic markers through linkage. Thus, the population can be constructed by hybridizing two dissimilar genotypes. It identifies the distance between the two linked genes, which in turn is used to construct a genetic map. Primary mapping populations are constructed by hybridizing two homozygous lines with distinct characters, while the secondary mapping population consists of hybridizing the individuals from a developed mapping population.
