Submitted to: Weed Science Society of America Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 2/9/2016
Publication Date: 3/9/2016
Citation: Gealy, D.R., Ziska, L.H. 2016. Influence of intermittent irrigation, red rice biotype, and rice grain type on outcrossing between red rice and imidazolinone-resistant rice. [Abstract]. Weed Science Society of America Meeting Abstracts. 56. Available; http://wssaabstracts.com/public/38/proceedings.html
Technical Abstract: Whether outcrossing rates between red rice and imazethapyr resistant rice are affected as a function of irrigation management is unclear. Potentially, differences between conventionally-flooded (CNV) and intermittently flooded (INT) systems could affect plant water deficits, as well as vegetative and reproductive development. The objectives of this study were to determine the rice-red rice outcrossing rates for two imazethapyr-resistant cultivars (CL 261, medium grain; CL 142-AR, long grain) and two red rice biotypes (PI 653437 strawhull [SH] and PI 653427 blackhull [BH]) under CNV and INT flood irrigation in a field study. We found that outcrossing occurred under both CNV and INT irrigation treatments, and between all four combinations of rice cultivar and red rice biotype. Outcrossing rates were highest with CL 142-AR as the rice cultivar and with red rice as the female (pollen recipient) of the cross. Irrigation method affected outcrossing minimally, suggesting that water deficit stress and other biological or environmental differences potentially present in INT plots were not sufficient to affect outcrossing in these experiments. However, it is yet to be determined whether greater flowering-time stresses, which are more likely during a drier summer, would alter the dynamics of rice-red rice outcrossing. A repeat of this experiment in which greater water deficits were imposed during flowering is underway.