Submitted to: Temperate Rice Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 3/10/2003
Publication Date: 3/10/2003
Citation: Gealy, D.R., Yan, W., Rutger, J.N. 2003. Characterization of hybrid populations from rice crossed with awned and awnless red rice. 3rd Temperate Rice Conference Proceedings. Paper #140, 7pp. (available on CD ROM only) Interpretive Summary: Interpretive summary not required.
Technical Abstract: Red rice (Oryza sativa L.) is a major weed of rice (Oryza sativa L.) in the southern U.S. and it intercrosses at low rates with the rice cultivars produced in this region. Knowledge of the plant phenotypes produced from such crosses may help farmers to accurately identify and manage crosses derived from specific red rice ecotypes and rice, including herbicide-resistant cultivars. F1 hybrids were produced by hand-crossing southern long grain tropical japonica cultivars, Kaybonnet-1789 (male sterile dominant) and Cypress-1819 (male sterile recessive), with awned and awnless U.S. red rice types. Parental, F1, and F2 (>150) plants from these crosses were transplanted to the field and grown under flooded conditions in 2002 at Stuttgart, AR. Phenotypic characteristics including culm angle, leaf texture, culm color, days to flowering, awn length, and seed bran color were determined. F1 plants produced pubescent leaves and red bran color, confirming that these were dominant traits. Crosses with awned red rice resulted in F1 plants with reddish-purple culms (not expressed in any of the parents) and flowering dates similar to both parents. Crosses with awnless Stuttgart strawhull red rice resulted in F1 plants with green culms and flowering dates much later than either parent. Crosses with awned red rice produced F1 plants with awns and F2 plants with awn lengths ranging from zero to the length of the red rice parent. F1 and F2 offspring from crosses with awnless red rice were awnless. F1 plants had an intermediate culm angle (similar to the red rice parent), while F2 plants produced culm angles ranging from erect (similar to the rice parent) to more open than the red rice parent. Based on these results, true F1 hybrids of rice and red rice (if homozygous) should be pubescent with red bran color and an open plant type. F1 hybrids may be awned or awnless, have purple or green stems, or have normal or delayed heading, depending on the red rice parental type. F2 hybrids have a wide range of phenotypic characteristics that may include combinations of all parental and F1 traits.