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Incidence and
severity of cotton leaf curl virus disease on different BG II hybrids and its
effect on the yield and quality of cotton crop
D. Monga and S.K.
Sain*
ICAR-Central Institute
for Cotton Research, Regional Station, Sirsa-125 055, India
*Corresponding Author Email : sain.skumar@gmail.com
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Abstract
Aim:
To understand the effect of Cotton Leaf Curl Disease incidence and severity
at various crop growth stages on Bollgaurd-II cotton hybrids having different
levels of susceptibility and resistance and its effect on, seed cotton yield
and fibre quality.
Methodology: The effect of cotton leaf curl disease (CLCuD)
incidence, severity and its progress on highly resistant to susceptible cultivars
was compared. The loss of seed cotton yield (SCY) corresponding to CLCuD
incidence at 80 DAS, 81-110 DAS, 111-140 DAS was estimated separately in each
hybrid. The loss of fibre quality corresponding to CLCuD incidence at seven
different stages, i.e., 50 to 140 days after sowing (DAS) was also
calculated.
Results:
The highest relative area under disease progress curve (AUDPC) values of PDI
were observed in Ankur 3028 (100%) and Ankur Jai BG II (83%), while the
lowest values were recorded in highly resistant hybrids Yuva-841-2 (4.6%) and
Bunty 2113-2 (13.8%). When the disease appeared up to 80 DAS compared to 110,
140 DAS the reduction range in SCY (4.6-62.4%), fibre length (23.9-29.9%),
strength (21.4-30.1%) and uniformity (62.5-83%) was recorded to be higher in
susceptible hybrids. The fibre length, strength, and uniformity were reduced
in diseased plant (25.9 mm, 24.4 g/tex, 68.2%) when incidence took place at
50 DAS compared to disease-free plants (27.6mm, 25.9 g/tex, 72.9%). However,
reduction in SCY, fiber length, fiber strength and uniformity at 80 DAS
varied with respect to hybrid and their resistance
category.
Interpretation: These results provide the basis to prove
the hypothesis that the yield loss is associated with the stage of CLCuD
incidence and its severity in cotton hybrids with different levels of
resistance as well as its genetic potential of a particular cotton cultivar.
However, the extent of yield reduction within the resistant or susceptible
category is also dependent on the yield potential of a particular cultivar.
Thus, breeders must consider both the criteria-lower PDI /AUDPC and higher
productivity to select high yielding cotton lines.
Key
words:
Cotton, Disease index, Leaf Curl Disease, Virus
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