Elimination of Potato viruses from the local land races through in vitro culture

Abstract

newline The present investigation on local landraces of potatoes from Assam was newlineconducted to eliminate the viral infections. For this the local landraces were collected newlinefrom different districts of Assam viz., Jorhat, Biswanath, Sonitpur, Barpeta, Dibrugarh newlineand Kokrajhar. Different symptoms like puckering of leaves, cupping of leaves, leaf newlinerolling, purple colouration on leaves, calico pattern, mosaic symptoms, crinkling of newlineleaves, etc. were observed. It was observed that the landrace from Barpeta had the newlinehighest disease incidence of 62.22 per cent and the lowest incidence of 10.00 per cent newlinewas observed in Badami aloo collected from Kokrajhar. PCR analysis of the newlinesymptomatic samples showed the presence of different viruses like PVY, PLRV, PVM, newlinePVX, PVS and AMV. The potato tubers were also subjected to PCR analysis and only newlinePLRV was detected with the highest incidence in Barpeta landrace (75.00 %). The newlinegrowth and yield attributing characters of the landraces collected were also recorded. newlinePlant height was observed to be highest in the landrace of Dibrugarh with 43.36 cm. newlineThe highest number of branches was observed in Dibrugarh landrace. The weight of newlinetubers per plant was observed to be highest in case of Dibrugarh landrace (383.48 g). In newlinethe in vitro studies, three types of explants (nodal segment, tuber eyes and apical newlinemeristem) with two types of media (MS and PM media) were used to conduct the newlineexperiment. Among the various hormonal combinations used for shooting, the best newlinehormonal combination observed was 2 mg/ l GA3 + 4mg/ l NAA + 2 mg/ l BAP newlineirrespective of the explant and media used in case of the parameters viz., time required newlinefor shooting, number of shoots developed and length of shoots. Similarly in case of newlinerooting the best hormonal combination observed was 1.5 mg/ l IAA + 1.5 mg/ l GA3 + newline1.5 mg/ l KIN irrespective of the explant and media used in case of the parameters viz., newlinetime required for rooting, number of roots developed and length of roots. The potato newlineplantlets survived highest (86.67 %) when g