Doubled Haploids in Plant Breeding What is a doubled haploid plant? Cells are the building blocks of plants. A doubled haploid plant has cells containing 2 gene sets which are exactly identical. Each cell contains 2 sets of genetic information which are almost (but not exactly) identical. For example, one gene set may carry a gene for disease resistance when How do doubled haploids accelerate breeding? Plants selected from a conventional breeding population do not Plants selected from a doubled haploid breeding breed true. population always breed true. Selected Plant Selected Plant Progeny: Progeny: This attribute of doubled haploids allows new Progeny: cultivars to be released 3 to 5 years earlier than with conventional breeding. Continue for 10-12 generations until all offspring breed true to type How are doubled haploids produced? Tissue culture of immature pollen Using tissue culture techniques referred to as “anther culture” and “isolated microspore culture”, immature pollen grains can grow to produce colonies of cells. The colonies are transferred to media with different plant growth regulators and sugars to induce growth of shoots and then roots. colonies shoot growth root growth genetic information (ie. It is This genetic information is duplicated “haploid”) in the culture process to produce a “doubled haploid”. Crossing with other species When barley is pollinated by the wild barley Hordeum bulbosum, the resulting embryos contain only the barley genes because the Hordeum bulbosum genes are excluded from the embryo.
If the embryos are cultured in vitro they will grow into haploid plants. Haploid Doubled Haploid Plant Haploid Plant Doubled Haploid
Haploid plants are sterile but can be converted to fertile doubled haploids by treating them with the chemical colchicine.
Wheat doubled haploids can be produced in a similar manner if wheat is pollinated with maize. Doubled haploids: tools for rapid oat breeding Benefits • True breeding plants in one generation Potential to produce cultivars 3 years earlier More efficient screening for grain quality and disease resistance
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http://www.miamiherald.com/news/miami-dade/north-central/story/970237.html Miami Gardens Junior Council stands against neighborhood violence BY Wilma Hernandez March 27, 2009 Every other Wednesday the Miami Gardens Junior Council meets at City Hall to talk about what is affecting the youth. The top priority in several past agendas: stopping violence. ''Stop the violence has been our them
Doubled Haploids in Plant Breeding
How are doubled haploids produced?
Doubled haploids: