24.01.2014 15:17

ARTICLE

Received 15 Jul 2013 | Accepted 4 Dec 2013 | Published 16 Jan 2014

Phytochrome RNAi enhances major fibre quality and agronomic traits of the cotton Gossypium hirsutum L

Ibrokhim Y. Abdurakhmonov¹, Zabardast T. Buriev¹, Sukumar Saha², Johnie N. Jenkins², Abdusattor Abdukarimov¹ & Alan E. Pepper³

Simultaneous improvement of fibre quality, early-flowering, early-maturity and productivity in Upland cotton (G. hirsutum) is a challenging task for conventional breeding. The influence of red/far-red light ratio on the fibre length prompted us to examine the phenotypic effects of RNA interference (RNAi) of the cotton PHYA1 gene. Here we show a suppression of up to B70% for the PHYA1 transcript, and compensatory overexpression of up to B20-fold in the remaining phytochromes in somatically regenerated PHYA1 RNAi cotton plants. Two independent transformants of three generations exhibited vigorous root and vegetative growth, early-flowering, significantly improved upper half mean fibre length and an improvement in other major fibre characteristics. Small decreases in lint traits were observed but seed cotton yield was increased an average 10–17% compared with controls. RNAi-associated phenotypes were heritable and transferable via sexual hybridization. These results should aid in the development of early-maturing and productive Upland cultivars with superior fibre quality.

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