Assessment of yield losses in Bt and non Bt cotton induced by cotton leaf curl virus disease (CLCuVD) in tolerant and susceptible varieties/lines in relation to epidemiological factors
2013
Sabir, Z.
Keeping in view the importance of this disease, the present studies were carried out to assess the effects of cotton leaf curl virus disease on yield traits of cotton especially plant height, number of sympodial and monopodial branches, boll weight, number of bolls per plant and 50% open boll under favorable environmental factors. Twelve different cotton genotypes were screened against the disease under field conditions. Out of twelve varieties/lines (VH-335, VH-309, VH-307, VH-306, VH-311, VH-327, VH-336, VH-340, VH-300, VH-281, VH-289, MNH-789) 7 varieties (VH-300, VH-311, VH-306, VH-327, VH-281, MNH-789 and VH-309) exhibited tolerant response, five varieties (VH-289, VH-340, VH-336, VH-307, VH-335) demonstrated susceptible response against cotton leaf curl virus disease. In case of Bt-cotton, maximum yield losses were recorded on VH-306 while remaining varieties revealed less yield losses. On the other hand, in non Bt-cotton varieties, maximum yield losses were demonstrated by MNH-789 followed by VH-281, VH-289 and VH-300 respectively. There was an overall negative correlation between vector population and air temperature (max and min) and wind velocity while relative humidity and rainfall exhibited positive correlation with vector population. Similarly, an overall negative correlation between max, min temp and wind speed while positive correlation of relative humidity and rainfall was observed with disease severity. The varieties with both groups responded differently against disease severity and vector population. Environmental conditions were conducive for CLCuV disease and whitefly development during the disease rating period.
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