Breeding of Aromatic Rice (Oryza sativa L.) Variety Khao Dawk Mali 105 through Multiple Shoot Induction and Gamma Irradiation

Abstract

Breeding of aromatic rice (Oryza sativa L.) variety Khao Dawk Mali 105 (KDML 105) for photoperiod insensitivity, short culm, high yielding, good cooking and eating quality of grains was conducted by using in vitro multiple shoot induction and gamma irradiation. The 357 M₁R₁ rice plants derived from multiple shoots which were induced from embryos irradiated with various doses of gamma radiation (0-36 krad). The M₁R₁ plants varied for the number of days to flowering, plant height, number of tillers and panicles per plant, seed fertility and lodging. The 1,108 M₂R₂ progenies showed photoperiod insensitivity, however the selection for other desirable agronomic characters could not be made due to the progenies which were infected by yellow orange leaf disease. The seeds were harvested from total 371 M₂R₂ plants which could produce seeds. In M₃R₃ progenies, selection was made for photoperiod insensitivity, short culm, high tillering, and erect plant type. Ninety-five M₃R₃ plants were selected. The M₄R₄ progenies responded to short day length which indicated that they were weakly photoperiod sensitive. The selection was made only for desirable agronomic characters. Thirty-one M₄R₄ lines were screened. The selection of M5R5 progenies was made by considering both good agronomic characters and good cooking and eating quality of grains. Four M₅R₅ lines were selected which possessed weakly photoperiod sensitivity, short culm, moderately tillering, erect plant type, good cooking and eating quality of grain with aroma. These lines will be utilized for further breeding of aromatic rice variety KDML 105 for photoperiod insentivity.