Morphomolecular charecterisation of the variants of piper nigrum L. variety panniyur -1

Abstract

The study entitled “Morphomolecular characterization of variants of Piper nigrum L. variety Panniyur-1” was conducted at the Department of Plant Biotechnology, College of Agriculture, Vellayani, Thiruvananthapuram and in the Block V of Panniyur-1 at the Regional Agricultural Research Station (RARS), Ambalavayal during the year 2006-2007 with an objective of characterizing the variants of black pepper variety Panniyur-1 based on morphological traits and RAPD profiles. Black pepper often referred to as the ‘King of spices’ is the most important spice in the world. The first ever hybrid of black pepper, Panniyur-1 (Uthirankotta x Cheriyakaniyakadan) is the most popular pepper variety grown in India and also in Kerala. In black pepper, propagation through cuttings is being practiced for decades for producing true-to type plants. However, contrary to this belief, there are reports for the existence of variability. Variability was reported even at the intraclonal level. The first such report in black pepper was in the local variety Karimunda (Ratnambal et al., 1985). According to Pradeepkumar et al. (1999), there exists intra-clonal variability in yield among the hybrid clone Panniyur-1 at the RARS, Ambalavayal. Such reports deserve serious concern and in depth analysis as pepper is a leading commercial crop of India, important in the domestic as well as international markets. The present study was taken up in this context utilising the progeny of the forty variant plants reported by Pradeepkumar et al. (2003) from the RARS, Ambalavayal. The objective was to assess the extent of variability with respect to morphological traits including yield parameters as well as the molecular analysis of genetic variability. On morphological analysis of the forty plants, considerable variation was observed. The maximum variation was observed in number of berries per spike followed by drying percentage. The analysis of the dendrogram showed that none of the plants were 100 per cent similar at a distance of 1.0. At a distance of 2.0 the clones can be grouped into five clusters. At a distance of 10, the plants can be grouped into two clusters comprising a major group with twenty-nine plants and a minor group with eleven plants. Molecular analysis also revealed variability, accounting for 66.34 per cent polymorphism. In the dendrogram at the similarity index 0.70 the plants grouped into two major clusters indicating thirty per cent dissimilarity. None of the plants were showed 100 per cent similarity. All the forty plants under study formed individual clusters at a similarity index 0.91 except V36 and V37. Ninety percent similarity was observed between the plants V20 and V30. At a similarity index below 0.70 the dendrogram showed a cluster including all the plants except V14. The present findings need further confirmation with more number of primers and other molecular markers like ISSR, AFLP etc. The occurrence of variability among the clones of Panniyur-1 in other major pepper growing tracts also needs to be investigated in detail.