Evaluation of mendok and dalapon as male gametocides and their effects on growth and yield of linseed

Abstract

Linseed plants were sprayed with aqueous solutions of Mendok (sodium 2,3-dichloroiso-butyrate) and Dalapon (sodium 2,2-dichloropropionate) at 250, 500 and 1000 ppm with a view to inducing male sterility. Both compounds produced more or less similar responses except that Mendok was slightly more effective than Dalapon. Toxicity symptoms consisted of hypo-nasty, chlorosis and slight to severe burning of young leaves and flower buds. Treated plants showed profuse branching, enhanced vegetative growth and heavy flower production. However, flowers became progressively smaller and gradually closed. Production and germination of seeds were both considerably reduced in the treated plants. Gamete fertility was reduced by almost all treatments. Female sterility was caused by decrease in size and abnormal morphology of pistils, and non-separation of styles and stigmas. Male sterility was induced in two forms: developmental and functional. The former was characterized by fully or partially barren anthers and non-viable pollen. Rhythms of pollen non-viability interspersed with periods of restoration of viability were noted. Functional male sterility resulted from lack of anthesis, fusion and non-dehiscence of fertile anthers and agglutination of pollen. The tapetal cells in the anthers of undersized flowers were highly vacuolate, radially stretched and they persisted up to the mature pollen grain stage. Another feature of morphological interest was the differentiation of microsporangia on petals. It is concluded that neither Mendok nor Dalapon can be used as a specific male sterilizing agent in linseed.