Embryo rescue from seedless grapevines (<i>Vitis vinifera</i> L.) treated with growth retardants

Abstract

The effects of two retardants (CCC and paclobutrazol) and the new compound XE 1019, applied before grapevine anthesis, were studied in order to increase the number of fertilised embryos and growing plantlets derived from in ovulo culture of seedless cultivars CG 102.011, Emperatriz and Malvinas. No significant differences were detected between treatments with CCC (400 and 800 mg . l^-1, applied 2, 3 and 4 weeks before bloom), and the control in the cv. CG 102.011. The number of growing plantlets at 10 weeks after anthesis and at maturity was significantly higher than that from 8 weeks. In applications closer to bloom, CCC treatments increased the number of ovules per berry in the cultivars assayed. From all cultivars, only CG 102.011 showed a significant increase in plantlet production after CCC treatment when clusters were harvested the 10th week after bloom. It is believed that CCC would act through inhibition of endogenous gibberellin synthesis as the cause of ovule abortion. The idea is based on the fact that gibberellic acid can induce seedlessness in some seeded cultivars.