Murad Ali

Detection of potato mop-top virus in soils and potato tubers using bait-plant bioassay, ELISA and RT-PCR

The hilly region of Northwest of Pakistan is leading seed potato producing areas of the country. Soil and plant samples were collected from the region and tested for PMTV using both conventional and molecular techniques. The bait plants exhibited PMTV-characteristic v-shaped yellow leaf markings in Nicotiana debneyi plants grown in putative viruliferious soils from 20/26 locations. The results were confirmed by back inoculation of sap from both roots and leaves of bait plant on indicator hosts (N. debneyi, Nicotiana benthamiana). The root samples of bait plants grown in soils of 25 locations and leaves of 24 locations reproduced systemic infection on indicator hosts upon back inoculation. The virus was identified in bait plants grown in soils from 25/26 locations using double antibody sandwich-enzyme linked immunosorbent assay (DAS)-ELISA and reverse transcription and polymerase chain reaction (RT-PCR) methods. The products of the 566bp were amplified from coat protein region of PMTV RNA 3 in both root and leaf samples of baited plants. The virus was detected in 10 potato cultivars commercially grown in the region using DAS-ELISA and RT-PCR. The virus was also detected in zoospores of Spongospora subterranea derived from the peels of selected scabby tubers using triple antibody sandwich (TAS)-ELISA. The results indicate that a bait plant bioassay, infectivity assay, ELISA and RT-PCR can detect PMTV in roots and leaves of baited plants, field samples, zoospores of S. subterranea and tubers of 10 potato cultivars commercially grown in the region.

Effect of Water Deficiency and Potassium Application on Plant Growth, Osmolytes and Grain Yield of Brassica Napus Cultivars

Abstract One of the major issues with brassica oil seed production is the water requirement of the brassica crop. To address the problem, field experiments were conducted to evaluate the effect of potassium (K) and water deficiency levels on canola (Brassica napus L.). Analysis of the data revealed that application of K, irrigation and interactions between irrigation and cultivar (I x C), irrigation and potassium (I x K), potassium and cultivar (K x C), and irrigation and cultivar and potassium (I x C x K) had a significant (p < 0.05) effect on shoot proline content, relative water content, plant fresh weight and grain yield. Potassium application, irrigation and interaction between I x C, K x C, and I x C x K had a significant (p < 0.05) effect on shoot sugar content. Water deficiency increased shoot proline and sugar contents and decreased relative water content. Potassium application increased shoot proline level in a dose dependent manner. Minimum proline and sugar contents and maximum relative water content, plant fresh and dry weight and yield were obtained when 100% irrigation was applied. Maximum grain yield was obtained upon application of 100% irrigation in combination with 120 kg ha−1 K.

WETLAND WATER MANAGEMENT THROUGH EFFICIENT OPERATION OF HYDRAULIC REGULATING STRUCTURES FOR OPTIMIZING THE FISH STOCK VIS-À-VIS AGRICULTURAL PRODUCTIONS

Fish, agriculture and water are closely interrelated in flood plain wetlands. Timely proper quantity and quality water is required for living and breeding of aquatic lives especially fish species. But the water required for fish may not be fully beneficial for agricultural productions in the polders/wetlands. That’s why conflict arises. Fishermen want to allow entering flood water at the beginning of monsoon (May-June) on the other hand farmers oppose the entering early flood water in to the polder/wetlands as at that time some crops remain in the field, which are not tolerant to that much water. There is a conflict among the farmers too. Farmers having lands at higher elevations and cultivate aman rice need water in the early monsoon but land owners those have land at lower elevations oppose seriously entering water and they are relatively influential. Hydraulic structures with the polders/wetlands are operating as per need and demand of its beneficiaries that was constructed with the aim of maximizing agricultural products and keep the area inside the polder flood free. During construction of these hydraulic structures no fisheries/aquatic habitats were concerned to the planners and designers except agriculture and flood even no longer term water environments was concerned. Most of the structures are undershoot type. When flood water passes through the gates, there are high velocity-turbulence and pressure differences that cause high mortality rate to migrating fishes especially to fish fries and fingerlings. Extensive studies have been carried out in two large polders/wetlands in association with IIED-UK, MRAG-UK and Bangladesh Centre for Advanced Studies on hydrological environment at hydraulic regulating structures sites (3 Nos.), fish migration and land use pattern inside the polders. Operations of flow regulating structures were also monitored systematically. Stochastic water balance model for the wetlands/polders have been developed utilizing spread sheet and applied to find out the impact of different parameters on the water level and land use pattern inside the polders/wetlands. From the study it is found that a protocol for the operation of the flow regulating structures can be developed to optimize the benefits of fisheries-agriculture that will also be helpful to enhance the livelihoods of the people. Configurations of the hydraulic regulating structures can also be modified to facilitate fish migration safely i.e., to convert it as fish friendly. Recommendation was made as from now care must be taken in planning and designing any hydraulic regulating structures so that it can be operated in a fish friendly mode and it was highly appreciated and accepted.