Resumen

ORTIZ DOMINGUEZ, Aída  y  OJEDA MUNOZ, Marjorien. Evaluation of the effect of different proportions of weedy rice variety types on milling quality of rice varieties. Agronomía Trop. [online]. 2006, vol.56, n.2, pp.199-218. ISSN 0002-192X.

Weedy rice-variety types (WRVT) produce severe losses in rice seed production in Venezuela, however this damage has not been evaluated in rice mills, therefore this study was proposed with the objective of evaluating the effect of four WRVT on certain attributes of milling quality of 2 rice varieties. D-Sativa seed was multiplied with its 2 WRVT, 1 of beige pericarp (DS-B) and the other 1 red pericarpe (DS-R); and Fedearroz 50 with its WRVT FD-B (beige) and FD-R (red), with isolation in space of 50 m of separation between them. Grain harvest was performed when grains had between 21 to 23% of humidity. Subsequently, when the humidity content (CH) of these grains decreased to 12±1, 4 trial were established in ASOPORTUGUESA rice mills, in Acarigua, Portuguesa State. An evaluated was performed of 11 physical mixtures of paddy rice between the two varieties and their WRVT with intervals of 10%, beginning at 0 up to 100%. A completely randomized design was used with five repetitions. Data were subjected to analysis of variance using SAS Software and mean Tukey at the 5% level of probability, as well as to regression analyses to each milling quality attribute against the percentage of weedy rice of the paddy mixture. Certain attributes associated with milling quality were also measured. The contamination with WRVT in the rice Paddy of D-Sativa and Fedearroz varieties linearly reduced head rice (HR) and increased the attribute of chalky+white grains; in the case of WRVT with red pericarp, these increased RR percentage of RR grains in HR. WRVT had a negative effect on milling quality of rice varieties, thus indicating that more kilograms of Paddy rice might be required to produced 1 kilogram of head rice with low percentages of de chalk+white grains and RR in polished rice in polished rice, when Paddy rice contaminated with this weed.

Palabras clave : Oryza sativa L; Paddy mixed proportion; weedy rice-variety types; varieties; milling quality.