Sex structure of hemp convergent hybrids

Abstract

Inbreeding and its extreme form (self-pollination) are an effective method for stabilizing the monoecious traits of industrial hemp. The hybrids with self-pollinated lines as the components of which, in most cases, were characterized by a better sex composition than the output cultivar forms, and the absence of male plants. The number of monoecious feminized plant (the main sexual type of modern varieties) in hybrids created as a result of crossing in the directions of vertical convergence was from 54.2 to 100.0 %, and in hybrids created by crossing in horizontal convergence it was from 37.7 to 100.0 %. The use of hybridization in the directions of vertical and horizontal convergence is advisable in the breeding of industrial hemp, especially for obtaining a starting material with a stable trait of monoecious, with high plant biomass, fber content and seed productivity. We recommend the following crosses: the frst and third generations of simple linear-varietal hybrids of various ecological-geographical types, related to one of the parental forms (F1 × F3) (i); crossing of simple interlinear hybrids of various ecological-geographical types with an inbred line of the Central European type of a later generation from self-pollination (interline hybrid × self-pollinated line) (ii); reciprocal crosses of simple interlinear hybrids of various ecological-geographical types with the original cultivar of a self-pollinated line of the middle European type (interline hybrid × cultivar and cultivar × interline hybrid) (iii); crossing of simple linear-varietal and intervarietal hybrids of the frst generation, related in one of the parental forms (iiii). The consistent use of crossbreeding, inbreeding (or divergence), hybridization (or crossing in the vertical and horizontal convergence directions) has created heterotic hemp forms with stable productive potential, homogeneous sex structure, and non-psychotropic properties. The created variety ‘Aurora’ is an example of an innovative breeding method. Key words: hemp, breeding, sex, monoecious, crossbreeding, inbreeding, divergence, convergence, hybrid, productivity.