摘要
Breeding for improved cultivars of existing crops depends mainly on the available amount of genetic variability in yield or quality related genes.For thousands of years,humans have relied on naturally occurring mutations to recombine and select improved crops.Using chemical or physical mutagens,the amount and range of mutations could be increased,accelerating the development of new traits.Nevertheless,naturally occurring or randomly induced mutations lead to unpredictable breeding outcomes and therefore necessitate tedious rounds of backcrossing to eventually produce useful phenotypes(Pacher and Puchta,2017).
