Biological World

 

 

 

  Pure Line Selection   Pure line selection is one of the oldest and most important methods of plant breeding. It is mainly used for the improvement of self-pollinated crops. In agriculture, many crop plants show natural variation in characters such as plant height, maturity, grain size, seed colour, disease resistance, and yield. A plant breeder studies this variation and selects the best plant from the available population. When the selected superior plant is self-pollinated generation after generation, its progeny becomes highly uniform and stable. This uniform and genetically similar group of plants is called a pure line.   The concept of pure line selection has played a major role in the development of improved crop varieties. It helped breeders convert variable local populations into uniform and high-performing varieties. The method is simple, scientific, and economical, so it has remained a fundamental topic in plant breeding courses. For undergraduate stud...

Major Objectives of Plant Breeding Program Plant breeding is an important branch of agricultural science. Its main purpose is to develop new and improved crop varieties. These improved varieties give better yield, better quality, and better resistance against diseases and harmful environmental conditions. A plant breeding program is planned according to the needs of farmers, consumers, industries, and climate. The major objectives of plant breeding are explained below in simple paragraph form. 1. Higher Yield The first and most important objective of plant breeding is to increase crop yield. Food demand is increasing due to rapid population growth, so breeders try to develop varieties that produce more grains, fruits, seeds, or biomass per unit area. High-yielding varieties help farmers earn more profit and improve food security. This is why yield improvement is considered the central objective of every breeding program. 2. Improved Quality Another major objective is to improve t...

IUCN The International Union for Conservation of Nature and Natural Resource (IUCN) plays a pivotal role in global biodiversity conservation by providing authoritative assessments and frameworks that guide environmental policy and scientific research. Established as a global authority, the IUCN’s primary contribution is its Red List of Threatened Species, which categorizes species based on their extinction risk. This categorization helps prioritize conservation efforts, informs sustainable development policies, and supports ecosystem management strategies worldwide. The Red List operates on a rigorous scientific methodology that evaluates species against criteria such as population size, rate of decline, geographic range, and degree of population fragmentation. These criteria place species in categories ranging from Least Concern to Critically Endangered, with some species classified as Extinct or Extinct in the Wild. This systematic approach provides a standardized language for conser...

Affinities of Anthoceros with other members. Anthoceros shows affinity with algae, members of Hepticopsida and Bryopsida of Bryophyta and Pteridophyta.The affinity and relationship of Anthoceros with green algae lies in the presence of a single large chloroplast together with a pyrenoid in cach cell of the gametophyte and in the formation of biciliated sperms. Anthoceros shows affinity with members of Hepaticopsida such as Riccia, Marchantia, etc. in the construction and structure of sex organs and in the apical growth of the thallus.It has affinity with members of Bryopsida i.e. Polytrichum, in the structure such as presence of columella, reduction of sporogenous tissue etc. and development of sporogonium. The spore production from amphithecium resembles the condition of that in Sphagnum. Anthoceros also shows sunken archegonium and development of antheridium from hypodermal initial cell like Pteridophyta. Highly developed sporophyte having photosynthetic tissue, functional stomata, i...