Int.J.Curr.Microbiol.App.Sci (2017) 6(8): 372-378 372 Original Research Article https://doi.org/10.20546/ijcmas.2017.608.050 Potential of Auxin in Inducing Spike Branching Trait in Black Pepper Smitha Bhasi 1 , Swapna Alex 1* , K.B. Soni 2 and Roy Stephen 2 1 Department of Plant Biotechnology, 2 Department of Plant Physiology, College of Agriculture, Vellayani-695 522, Kerala, India *Corresponding author ABSTRACT Introduction Black pepper, referred as „King of spices‟ is a major export oriented spice crop of India. Normally, black pepper species have non- branched spikes. A pepper type viz., „Thekken‟ a selection of Piper nigrum, made by a farmer in Idukki, Kerala exhibits profuse branching character with more than 30 well developed branches bearing about 300 berries altogether as shown in figure 1 which is a trait of high economic value that is directly linked to the yield potential. The yield of berries from spikes of black pepper „Thekken‟ is reported to be about four times that of the highest yielding varieties, Panniyur-1, Panniyur-3 Panniyur-5 and local varieties like „Karimunda‟ (ICAR, 2010; Subba et al., 2014; Vimarsha et al., 2014). Flowering is a highly regulated process (Hsing, 2011) and is influenced by multiple factors including environment and developmental signals. Inflorescence architecture observed in nature is found to be highly diverse and observed in many plants (Brown et al., 2006). Growth regulators such as auxins, cytokinins and carotenoid derivatives are reported to International Journal of Current Microbiology and Applied Sciences ISSN: 2319-7706 Volume 6 Number 8 (2017) pp. 372-378 Journal homepage: http://www.ijcmas.com Black pepper, the „King of Spices‟ has high value in the international market. Natural varieties of Piper nigrum (black pepper) usually have non-branched spikes. However, a natural selection of black pepper viz. „Pepper Thekken‟, shows inflorescence branching character i.e., about 20-30 branches per spike which is a trait of high economic value that is directly linked to the yield potential of this valuable spice crop. Auxin polar transport is reported to be one of the regulatory factors for branching architecture in many plants. Hence, in the present study, we tried to analyse the role of auxin in inducing branching trait in „Thekken‟ through quantification of Indol acetic acid content in immature spikes using HPLC and comparing it with that of non-branching varieties like „Karimunda‟ and “Panniyur- 1”. The study revealed that the IAA content in the spikes of branching variety „Thekken‟ was significantly low, that is about 1/4 th and 1/3 rd of „Panniyur‟ and „Karimunda‟ respectively. Keywords Black pepper, Spike branching trait, Indole-3- acetic acid (IAA), HPLC. Accepted: 04 June 2017 Available Online: 10 August 2017 Article Info