Morphological and molecular characterization of byadagi chilli (Capsicum Annum L.)

Abstract

Byadagi is a famous chilli type grown in Karnataka and is named after the town “Byadagi” which is located in Haveri district of Karnataka. This chilli is known for its deep red colour and negligible or zero pungency. The demand for Byadagi chilli has increased enormously as a source of natural red colour in food industry. Spices Board has taken steps to protect Byadagi chilli under GI registration. The investigations on “Morphological and molecular characterization of Byadagi chilli (Capsicum annuum L.)” was carried out at the Centre for Plant Biotechnology and Molecular Biology (CPBMB), College of Horticulture, Kerala Agricultural University, Thrissur during July 2013 - June 2014. The study was aimed to characterize Byadagi chilli using morphological and molecular markers with special emphasis on colour and pungency. Two Byadagi chilli cultivars viz. Byadagi Kaddi and Byadagi Dabbi and two KAU released varieties viz. Ujwala and Anugraha were characterized in the study. The variety Ujwala was selected for its high pungency and variety Anugraha for its less colour on drying. Morphological characterization was done as per NBPGR minimal descriptor for chilli. Molecular characterization was done using two different marker systems viz. RAPD and ISSR. Twenty one qualitative and sixteen quantitative characters were recorded as per minimal descriptor. Byadagi cultivars possessed dark green medium sized leaves, dark red ripened fruits with wrinkled surface, higher fruit weight (6.27 g), less number of fruits per plant (17.21), more number of seeds per fruit (97.49) and lesser fruit yield (100.12 g). KAU varieties viz. Ujwala and Anugraha recorded more number of fruits per plant (88.08) with less fruit weight (1.79 g) and higher fruit yield (152.4 g) with red coloured ripened fruits with smooth surface. The dried fruits were analysed for colour and pungency at Spices Board quality evaluation laboratory, Kochi. Byadagi cultivars recorded higher colour value (108.92 ASTA) and lower pungency (0.045 per cent capsaicin) while KAU varieties viz. Ujwala and Anugraha possessed lower colour value (59.1 ASTA) and higher pungency (0.32 per cent capsaicin). The RAPD marker system could generate a total of 155 amplicons with fourteen primers exhibiting an average polymorphism of 65.23 per cent and 7.14 polymorphic amplicons/ primer. The ISSR marker system could generate a total of 103 amplicons with eleven primers exhibiting an average polymorphism of 61.35 per cent with six polymorphic bands per primer. The dendrogram generated with RAPD, ISSR and combined profiles grouped Byadagi cultivars and KAU varieties in separate clusters. The varieties Ujwala and Anugraha were found closer with 67 per cent similarity and Byadagi Kaddi and Byadagi Dabbi with 61 per cent similarity. Eight amplicons resolved with five primers (S12, S13, OPAH 06, OPA10 and OPE18) in RAPD marker system and twelve amplicons resolved with seven primers (2UBCS2, ISSR05, ISSR08, ISSR15, UBC823, UBC840 and 17899A) in ISSR marker system were found specific to Byadagi Kaddi and Byadagi Dabbi. The morphological and molecular characterization attempted in the present study could distinguish the Byadagi cultivars from the KAU varieties , Ujwala and Anugraha with respect to colour and pungency. The specific traits of Byadagi cultivars like high colour and low pungency are expressed in a similar fashion under Kerala conditions also. In depth investigations on the unique amplicons identified specific to Byadagi cultivars will give further insight into the genes involved in colour and pungency of chilli, which could be utilized further in marker assisted selection, metabolic pathway engineering and secondary metabolite production.