It is used not only for the developing hybrid but to test the combining ability of the inbreeds. 6). 8). Seeds are space planted and single plant selection is done (F7 generation). In such case,it is important that the two parents should combine well to produce an outstanding F1. Hybrid rice increases yields between 5% and 15% over inbred varieties and China’s “super” rice achieves yields of 12 tonnes per hectare or 8% to 15% more than other hybrid varieties. Essay # 4. 2000-10000 F2 plants are space planted. In such small hermaphrodite flowers (e.g., Bajra, Jowar) emasculation is done by dipping the flowers in hot water for a certain duration (1-10 minutes) of time. Such crosses are called distant crosses. For example producing high quality seeds that are superior to the parent.This is possible by inducing the desirable characteristics into an existing variety so as to overcome it’s defects or weaknesses.Technically this process is known as hybridization. Genetic improvement of various crop plants has been done by adopting the following three steps : Introduction, Selection and Hybridization. The selection of parents depends upon the aims and objectives of breeding. The first artificial interspecific plant hybrid was produced by Thomas Fairchild in 1717. It is the science involved in improving the varieties of crops by breeding plants. What could be the reason for increasing the demand of food? B is then donor or non-recurring parent and A is recipient or recurring parent. (ii) Inter-varietal or Intraspecific hybridization: The crosses are made between the plants belonging to two different varieties. Nilsson-Eule of Sweden was first to use the bulk method and it is in use ever since. Hybrid Cultivar Development (Hybrid Breeding) References. Good quality seeds must be provided to the farmers. Tissue Culture: The growth of tissues of living organism in a suitable culture medium (in vitro)I is … Legumes and dried beans have a longer shelf-life and are cheap to buy. F3 plants are grown and their F4 seeds are harvested in bulk. Hybridisation is a central process in plant breeding. This method is also known as the mass or population method. Process is continued as in F3 generation. It is the sixth step. When two genotypically different plants are crossed, the genes from both the parents are brought together in F1. Two crops of good characters (desired character) are selected and crossed to obtain a new crop having desired characters of parental crops. These characters may be governed by oligogenes or polygenes.In this approach, increase in yield is obtained by correcting the weaknesses in the yield contributing traits like tiller number, grains per panicle, seed weight of the concerned variety. It can be defined as a cross among inbreeds, clones or sibbed lines without control of pollination. Seeds are stored properly with original tags. For maintaining good health, we require food. F1 plants are space planted to produce maximum number of F2 seeds (see Fig. It requires lot of time and money. (ii) Hybridization has to be done for each backcross. Normally 20-50 families may be retained at the end of F5 generation. The shortest duration of the crop from sowing to harvest is the most economical method of the varieties.Such shorter durations allow farmers to grow multiple rounds of crops in a year. It is similar to its parents in all qualities, excepting dark green What is the significance of transpiration? This is a question and answer forum for students, teachers and general visitors for exchanging articles, answers and notes. Hybridisation is the crossing between genetically dissimilar plants to obtain crops having useful characteristics like disease resistance,good- … The natural or artificial process that results in the formation of hybrid is known as hybridization. Acknowledgements. Extensive yield tests are not required because the performance of the recurrent parent is already known. Breeder does not require to handle large populations. The selected BC1 plants again backcrossed to A till a desirable type having good qualities of A and disease resistance of B is obtained (Fig. They are served as a staple food for the majority of population. (iii) Sometimes undesirable genes are closely linked with desirable one and get transferred to the new variety. In alfa-alfa, a treatment of even 10 seconds with 57 % alcohol is sufficient to kill the pollen grains. The crosses are made between the plants of the same variety. Desirable clones are crossed together and the hybrids are multiplied by cloning. F2 plants are grown and their F2 seeds are harvested in bulk. Discuss the role of hybridisation on crop improvement 2 See answers Answers reemabiswas982750 Helping Hand; any singal variety of plant species may not possess all the useful characters. These crosses generally have wider adaptation. Before sharing your knowledge on this site, please read the following pages: 1. Selection for plants in the desired combination of characters is started in the F2 generation and continued in succeeding generations until genetic purity is reached. In the coming season, the stored seeds are sown separately to raise the F1 generation. Crop variety improvement. Following are the important precautions while performing this method: i. This website includes study notes, research papers, essays, articles and other allied information submitted by visitors like YOU. (ii) Selfing of parents or artificial self-pollination. (iii) There are chances of recovering transgenic segregation by this method. Principles of Plant Breeding. Welcome to BiologyDiscussion! This method was first proposed by Harlan and Pope (1922). Improved clones of asexually propagating plants are selected and allowed to grow under conditions, which favour flowering and seed setting. From these it is possible to understand the reasons for the improvements in yield. The transfer of one or few qualitative characters. The degree of variation produced depends on the number of heterozygous genes in F1. Transfer of some genes from one species into the genome of the other species is known as introgressive hybridization. CROP VARIETY IMPROVEMENT For this purpose, a crop variety is chosen which can give good yield. Preliminary yield test are conducted (F9). 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