Sexual expression of castor influenced by fertilizer and mepiquat chloride

Abstract

Trend for maleness in castor flowers (Ricinus communis) is probably one of the reasons for reducing yield in some genotypes when cultivated at low altitude. Sexual expression in several plants is a physiological process regulated by plant hormones, mainly gibberellins and cytokinins. This study aimed to the evaluate effect of five doses of growth plant regulator mepiquat chloride (0.08%; 0.16%; 0.24% e 0,32%) and presence / absence of mineral fertilization on characteristics related to growth and sexual expression of castor plants. Mineral fertilization influenced characteristic related to growth, such as: number of fruits, number or length of male and female nodes. However it did not influenced characteristics related to sex expression, while mepiquat chloride had effect on the number of female flowers, ratio of female:male nodes and ratio of female number nodes: length. We concluded that is possible to shift sexual expression and the doses 0,08% and 0,16% were most effective on feminization of castor plants.