Screening and identification of Piper species as rootstocks resistance against the root knot nematode under glasshouse condition

A study was conducted to evaluate the reaction of different Piper species to root knot nematode (Meloidogyne incognita) and the nematode reproduction were studied in the nematode infested pot culture experiment. Three Piper species viz., Piper colubrinum, Piper argyrophyllum and cultivated Piper nigrum varieties of IISR Sakthi, IISR Thevam, Panniyur-1 and Karimunda were screened.  In this study, seven rootstocks were evaluated for resistance based on the growth of pepper cuttings and resistance indexes to Meloidogyne incognita, which were surveyed 45 days after inoculation with M. incognita. The observation was recorded viz., nematode soil population (200 cc), number of galls, number of egg mass, number of females, gall index. All the Piper species show varying degree of response. Out of seven rootstocks used in this experiment IISR Sakthi were found to be  highly resistant, Piper colubrinum, IISR Thevam and Karimunda resistant to root knot nematode and these cultivars can be used as a source of resistance. Black pepper (Piper nigrum L.), in particular, suffer extensive damage due to root-knot nematodes, and only a few wild species are known to be resistant. Grafting of cultivated plants to rootstocks of known resistant Piper species rootstocks could be an effective method to resolve this problem

FISSR-PCR: a simple and sensitive assay for highthroughput genotyping and genetic mapping

The recently developed Inter-Simple Sequence Repeat PCR (ISSR-PCR) or microsatellite primed PCR or Simple Sequence Repeat (SSR)-Anchored PCR technique detects polymorphic markers in a wide variety of genomes. Usually the ISSR primers are either 5' end-labeled with γ[32P]ATP or one of the α[32P] labeled dNTPs is added to the PCR reaction and the PCR products are resolved on PAGE and autoradiographed. Alternatively, cold PCR products are resolved on agarose gel electrophoresis. In the present study, we show that informativity, sensitivity and speed of the ISSR-PCR can be substantially enhanced by adding fluorescent nucleotide in the PCR reaction followed by resolution of PCR products on an ABI 377 automated sequencer. The informativeness, measured as a number of detectable amplified fragments, was two-fold higher and the quantity of required template DNA is two-fold lower than the regular ISSR-PCR. We have termed this method as FISSR-PCR and show its usefulness in generating large number of species and varietal specific markers in plants, insects, parasites of insects and human and various infectious organisms. Further, we show that the FISSR markers are inherited and segregated in Mendelian fashion as demonstrated on a panel of 99 F2 offspring derived from a cross of two divergent silkworm strains. The FISSR-PCR marker assay could be a method of choice for large scale screening of varieties/cultivars and highthroughput genotyping in mapping of genomes where microsatellite information is scanty or absent