Effect of Phytohormones on Shoot Proliferation of Doubled Haploid Lines of African Marigold (Tagetes erecta L.)

In vitro propagation of marigold has played a very important role in rapid multiplication of cultivars with desirable traits and production of healthy and disease-free plants. Shoot proliferation is a very important phase of micropropagation. This paper describes an efficient protocol for In vitro micropropagation of Doubled haploid lines of marigold (Tagetes erecta L.) using nodal explants. Murashige and Skoog medium (MS) supplemented with various concentrations and combinations of Benzylaminopurine (BAP), Naphthylacetic acid (NAA), Gibberellic acid (GA3) and Thidiazuron (TDZ) were employed for shoot regeneration in this study, maximum percent sprouting (100%) and minimum days to sprout break (1.48) were found in MS media supplemented with BAP 2mg/L + NAA 0.05mg/L + GA3 1mg/L, while maximum number of sprouts (1.73) and maximum average shoot length (3.98cm) were observed in case of media supplementation with BAP 1mg/L + NAA 0.05mg/L + GA3 0.5mg/L. However, in case of Thidiazuron (TDZ) minimum days taken for shoot proliferation (2.66) and maximum number of shoots per micro shoot (7.04) were observed in media supplemented with BAP 1mg/L + NAA 0.1mg/L + TDZ 0.5mg/L, while maximum length of shoots (4.2cm) was observed in control devoid of any hormones.