MADRAS AGRICULTURAL JOURNAL

Characterization of Xanthomonas axonopodis pv. punicae (Hingorani and Singh) Vauterin et al. and Isolation of Xap Specific Bacteriophage

Abstract

                                Bacterial blight (BLB) caused by Xanthomonas axonopodis pv. punicae (Xap) has emerged as a potential threat in pomegranate cultivation in India. To know the present disease scenario and to identify the root cause for its epidemic, survey was conducted in five different localities of Tamil Nadu. Per cent disease severity (PDS) ranged from 1 to 36 per cent on leaves and zero to 40 per cent infection on fruits. Bacteriophage or bacteria killer specific to Xap-1 (Sennampatty) isolate was isolated from pond water after enrichment of water sample. Phage produced plaques of 2 mm, 1 mm and < 1mm size that coalesced after 18 h of plating which shows virulence and rapid phage multiplication. Disease severity on test plants were studied to know the degree of virulence and variability among the isolates with highest severity of 37.31 per cent documented in Xap-1 followed by Xap-3 (28.7%) and Xap-2 (24.3%). Physiological factors such as temperature, pH and their role in growth of Xap-1 were accessed. Maximum growth was observed at 28˚C (0.86 OD) followed by 30˚C (0.68 OD) and pH 7 (1.83 OD) and optimum at 7-8 pH for virulent (Xap-1) isolate. Molecular confirmation of Xap through 16S rRNA sequencing gave the amplicon of 1500 bp size and amplification through KKM5 and KKM6 further confirmed specific identity.

Key words : Pomegranate, Bacterial blight, Bacteriophage, Physiological and molecular characterization

Copyright @ 2019 Madras Agricultural Journal | Developed by Crystalpro All right reserved.

Brinjal is the most common and popular vegetable crop. The application of composts and organic amendments influence organic matter and nutrient cycling and increase soil nutrient level. Pot experiment was conducted in Department of Soil Science and Agricultural Chemistry, Annamalai University to evaluate the response of brinjal with conventional, non-conventional organic sources, industrial by-products combined with inorganic fertilizers. The treatments imposed were T1 -Control (100% RDF), T2 -T1 + Municipal solid waste compost @ 5 t ha-1, T3 -T1 + Municipal solid waste compost @ 10 t ha-1, T4 -T1 + Vermicompost @ 2.5 t ha-1, T5 -T1 + Vermicompost @ 5 t ha-1, T6 -T1 + Rice husk ash @ 5 t ha-1, T6 -T1 + Rice husk ash @ 5 t ha-1, T7 -T1 + Rice husk ash @ 10 t ha-1, T8 -T1 + Lignite Fly ash @ 5 t ha-1, T9 -T1 + Lignite Fly ash @ 10 t ha-1. There were nine treatment combinations replicated thrice in CRD. The soil was sandy in texture pH 7.83 (saline), EC 0.22 dSm-1, available N (257 kg ha-1), available P (10.2 kg ha-1) and available K (117 kg ha-1) respectively which fell in fertility status of low. The soil classified taxonomically as Typic udisamments. The results showed that application of 100% RDF + Vermicompost @ 5 t ha-1 (T5 ) significantly recorded brinjal fruit yield of 934.2 g plant-1 and brinjal stover yield of 403.7g plant-1. The post harvest organic carbon content (3.5 g kg-1), available N (148 mg kg-1) available (7.15 mg kg-1) recorded in the treatment T5 which received 100% RDF + Vermicompost @ 5 t ha-1. The post harvest available K (77.48 mg kg-1) was registered with application of 100% RDF + Lignite Flyash @ 10 t ha-1 (T9 ).

Key words : : Brinjal, Municipal solid waste compost, Vermicompost, Rice husk ash, Lignite flyash. .

Copyright @ 2019 Madras Agricultural Journal | Developed by Crystalpro All right reserved.

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    Copyright @ 2019 Madras Agricultural Journal | Developed by Crystalpro All right reserved.