Screening of USDA Cotton Accessions against Sucking Insect Pests Complex and Cotton Leaf Curl Virus (CLCuV) Disease with Major Emphasis on Abiotic Factors
Screening of USDA Cotton Accessions against Sucking Insect Pests Complex and Cotton Leaf Curl Virus (CLCuV) Disease with Major Emphasis on Abiotic Factors
Syed Ishfaq Ali Shah1,*, Tassawar Hussain Malik2, Imran Rafi Khan1 and Zahid Hussain3
ABSTRACT
This study was conducted to evaluate the germplasms imported from United State Department of Agriculture (USDA), United State of America (USA) primarily for Cotton leaf curl virus (CLCuV) disease with promising local varieties tolerant to the disease. After screening, the most resistant accessions of USDA were USG-14-2464 and USG-14-2478. However, USG-14-2481 and USG-14-2484 were recorded as partially resistant to CLCuV disease. Among the local germplasms, all accessions screened were found extremely susceptible. Disease index increased with day after planting (DAP) and high infestation level of whiteflies as it was positive and non-significantly correlated with DAP and whitefly on both USDA accessions and local varieties. Maximum and minimum temperatures, rainfall and wind velocity were negative and non-significantly correlated while, % relative humidity (%R.H) was found non-significantly and positively correlated both with USDA accessions and local varieties. On overall basis, during the course of the season, lowest number of jassid/leaf was recorded on USG-12-8 (1.7) followed by USG-12-44 (3.2) and USG-12-24 (3.3) while, number of whiteflies/leaf on USG-14-2460 (11.6) followed by USG-12-24 (12.4) and USG-14-2478 (12.7) whereas, highest resistance was recorded against thrips in all accessions. Among the local varieties, lowest jassid/leaf was noted on desi/arborum (0.8) followed by AA-703 (3.6) and AA-802 (3.7) while, whitefly (12.8) and thrips (0.4) on desi cotton. The most sensitive planting date (DAP) of the crop for jassid both on USDA accessions and local varieties were 30 DAP (June-July), for whitefly 90 DAP (August-September) and partially only on local varieties, 30-60 DAP (June-August) for thrips. Maximum temperature and wind velocity promoted jassid population both on USDA and local varieties while, %R.H and rainfall decreased it. Maximum temperature and wind velocity decreased whitefly on USDA accessions whereas, these positively favored (increased) on local varieties. Increased in %R.H efficiently developed whitefly on USDA accessions while, non-significantly on the local varieties however, rainfall was found non-significantly positively correlated with USDA as well as local. Thrips increased with increase in maximum and minimum temperatures, rainfall and wind velocity on USDA and local varieties while, increase in %R.H resulted to promote thrips on USDA accessions while it declined on local varieties.
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August 2017
Vol. 49, Iss. 4, Pages 1151-1546
