Fecha de publicación: 06/09/2013 Fuente: WIPO Agriculture Portada Improvement of fiber quality of Upland cultivars (Gossypium hirsutum), while maintaining early maturity and productivity, is a fundamental problem in conventional cotton breeding. Phytochromes play a fundamental role in plant development, flowering and cotton fiber length. Targeted RNAi of PHYA 1 genes in cotton suppressed expression of PHYA 1 and/or PHYB, resulting in over-expression of the remaining PHYA2/B/C/E genes. This altered expression induced a number of phytochrome- associated phenotypes, including increased root length and mass, increased anthocyanin-pigment, vigorous shoot development and vegetative growth, early flowering, early boll maturity, increased fiber length and increased seed cotton yield compared to control plants. These RNAi phenotypes were stably inherited and expressed through four generations (T0-3) and were transferable from RNAi Coker-312 plants to Upland cultivars via conventional hybridization. These effects in Upland cotton breeding can offer a new paradigm in cotton breeding resulting in the development of productive, early-maturing Upland cultivars with increased fiber length and fiber strength.