Efficacy of Major Plant Extracts/Molecules on Field Insect Pests

Insect pests are considered the major hurdle in enhancing the production and productivity of any farming system. The use of conventional synthetic pesticides has led to the emergence of pesticide-resistant insects, environmental pollution, and negative effects on natural enemies, which have caused an ecological imbalance of the predator-prey ratio and human health hazards; therefore, eco-friendly alternative strategies are required. The plant kingdom, a rich repertoire of secondary metabolites, can be tapped as an alternative for insect pest management strategies. A number of plants have been documented to have insecticidal properties against various orders of insects in vitro by acting as antifeedants, repellents, sterilant and oviposition deterrents, etc. However, only a few plant compounds are applicable at the field level or presently commercialised. Here, we have provided an overview of the broad-spectrum insecticidal activity of plant compounds from neem, Annona, Pongamia, and Jatropha. Additionally, the impact of medicinal plants, herbs, spices, and essential oils has been reviewed briefl

Diversity Studies Using Molecular Markers

The introduction of molecular markers in the latter part of the twentieth century denoted a major advancement in the research on plant genetics. Molecular markers have become highly advantageous to help overcome certain inherent difficulties associated with the genetic improvement of perennial crops such as coconut. Starting from the middle of the 1990s, considerable progress has been achieved in the genetic diversity analysis of coconut. The early attempts of molecular research on coconut used the common molecular marker systems of the time, such as randomly amplified polymorphic DNA and amplified fragment length polymorphism. Later, the generation of coconut-specific DNA markers and the adoption of high-throughput systems have paved the way for an acceleration, with greater accuracy, in using molecular markers for diversity studies in coconut. Molecular markers have also been used in the development of linkage maps and the identification of quantitative trait loci (QTL) in coconut. The research using molecular markers has been used, and will be further useful, in formulating and refining the further collection and conservation of coconut germplasm, the management of genebanks, identification of duplicates, and determining the strategies for rejuvenation of the existing field genebanks. The data can further be used in the parental selection in the coconut breeding programmes aimed at combining the desirable characters from diverse parents into novel cultivars. The availability of high-throughput marker systems will increase the accuracy and precision of genetic and QTL mapping via linkage analysis. Further, association studies which facilitate the use of existing populations in QTL mapping will be an important tool in moving towards marker-assisted selection of coconuts for desirable traits to ensure sustainability of the coconut industry