How some native upland rice and cultivated lowland rice varieties responded to callus induction and regeneration medium?

The seed collected from ethnic farmers (Pa-gha-ker-yor People), at Pala U village, Hau Hin district, Prachuap Khiri Khan province, Thailand for genetic conservation and investigating feasibility for breeding and improvement. For genetic improvement, information on either some qualification or ability to assist in the breeding process is required, such as the ability to culture seed, explants or other tissues in a sterile laboratory condition. The objective of this study evaluated the effectiveness of callus induction and regeneration upland rice seeds (var. Nikor, var. Raw Bi, var. Gi Poo and var. Nah San, var. Baw Pae Soo and var. Pae Taw Gaw Bi) collected from minority farmers and some lowland cultivated rice varieties (var. RD51 and var. Pratumtani1) in Thailand. The culture medium used in the study were derived from the previously reported formulations that are highly effective in inducing callus (MS1, MS2 and MS8) and regenerating (MS1, MSa and MSb) in rice. The different formulas in medium were from various combinations of plant growth regulator both or either on cytokinin (Benzyl aminopurine; BAP) and/or auxins (Napthalene acetic acid; NAA, 2,4-dichlorophenoxy acetic acid; 2,4-D) for callus induction and regeneration. For statistical analysis, the data have been analyzed using analysis of variance (ANOVA). The means among treatments were compared with the Duncan’s new multiple range test (DMRT). The results showed the increasing on callus induction percentage were recorded on MS2 (86%) and MS8 (90.5%) mediums studied on immature and mature seed, respectively. The callus of upland rice varieties induced on a medium which showed higher percentage (90.5% callus induction on MS8 and 0% on MS1) were selected to shoot regeneration experiment contained three media (MS1, MSa, and MSb). However, in the regeneration process, there is no significant difference between medium; the percentage of regenerating callus of these media at 6.25%, and the interaction between media and varieties of rice.