Abstract

ORTIZ DOMINGUEZ, Aída; MIRANDA, Rubén; FIGUEROA, Rosana  and  RAMIS, Catalina. Morphological characterization of a F₂ progenies obtained from natural crossing between rice variety and red rice (part I). Agronomía Trop. [online]. 2008, vol.58, n.3, pp.299-307. ISSN 0002-192X.

The objective of this study was to characterize the F₂ progeny obtained from crosses between the variety of rice "ZETA 15" and the black glumes red rice (RR) without awn, in order to explain to rice producers how weedy rice variety types (WRVT) may be originated. Descriptive statistics were used and the test of Ji-square for plant height. Eight morphologic characteristics were evaluated. Results showed that F₂ progenies had segregation in all the evaluated characteristics, mainly in plant height up to the panicle where a minimum value of 35 cm and a maximum of 166 cm were observed; tiller number was 5 to139 and growth habit open, intermediate, and erect. Days to flowering of the F₂ showed that 96% of the individuals flowered earlier than the parents, between 100-112 days after seeding (das), 2% had 109-112 das and 1.63% between 100-103 das, while RR had 114 and ZETA 15® 117 das. The presence of individuals having similar characteristics to the variety, such as small plants, intermediate or erect growth habit, as well as similar flag leaf length, panicle exertion and days to flowering, indicates the possibility that they may convert into WRVT if the process of selection by the purification of fields occurs, confirming that the occurrence of these mimetic forms of rice in seed fields perhaps is because of the flow of pollen between cultivated rice and red rice.

Keywords : Oryza sativa L; Rice; Red rice; F₂; morphology.