|Developing Chromosome Segment Substitution Lines to Understand Transgressive Variation|
This illustrates the plants obtained after crossing the ancestral rice species to the cultivated rice parent, IR64, for three generations. Notice the plants become more like IR64. The backcross method, is being used to develop the sets (libraries) of chromosome segment substitution lines (CSSLs). In the backcross method, the hybrid plant is crossed to the cultivated parent several times.
The world population is predicted to be 9 billion people by 2050. To keep pace with the growth, it is important to increase the rice yields to meet this need. Earlier studies showed that incorporating DNA from the ancestral rice species Oryza rufipogon into cultivated rice increases yields through the phenomenon called hybrid vigor or transgressive variation. Currently, we are developing six libraries. Each library is a set of chromosome segment substitution lines (CSSLs) with a particular segment of the ancestral Oryza rufipogon parent in the background of cultivated rice. These libraries can be used to increase yield in new rice varieties developed by rice breeding programs.
This picture shows the genotypes of the 63 lines selected for one set (library) of chromosome segment substitution lines derived from a IR64 (cultivated rice) x Oryza rufipogon (ancestral rice) cross. Each row represents the genotype of a particular chromosome segment substitution line.
This project is funded in part by the National Science Foundation PGRP #1026555. See http://www.ricediversity.org/for more information. (external link)
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