Assessment of Physiological Efficiency in Bt and Non-Bt Cotton Hybrids
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Date
2012
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Publisher
UAS, Dharwad
Abstract
A field experiment was conducted during 2011-12 under rainfed condition at
Agricultural Research Station, Dharwad to assess the physiological efficiency in Bt
and non-Bt cotton hybrid. The experiment consisted of five Bt hybrids and their non
Bt counterparts comprising ten treatments and laid out in a randomized block design
with three replications.
Among the genotypes JK-Durga Bt hybrid produced significantly higher seed
cotton yield (3032 kg/ha) followed by MRC-7351 Bt (2915 kg/ha) and least was
recorded by MRC-7301 non-Bt (2223 kg/ha). Further, JK-Durga Bt recorded
significantly high boll weight, boll number as compared to other genotypes. In general
Bt genotypes recorded more boll weight and more boll number as compared to their
non-Bt counterparts. Significantly more total nitrogen content in leaves, stem and
bolls was recorded by JK-Durga Bt genotype at 140 DAS as compared to other
genotypes. Significantly more photosynthesis rate, transpiration rate, relative water
content and chlorophyll content was recorded in JK-Durga Bt followed by MRC-
7351 Bt at 110 DAS as compared to other genotypes, while at 140 DAS non-Bt
genotypes recorded more photosynthesis rate, transpiration rate and chlorophyll
content than their Bt counterparts.
Genotypes differed significantly in their growth pattern, morphological and
phonological characters. Non-Bt hybrids recorded more plant height, LAI and SLW
compared to their Bt counter parts at 140 DAS indicating more vegetative growth in
non-Bt genotypes. The number of days taken for 50 per cent squaring, 50 per cent
flowering, 50 per cent boll opening, was significantly less in Bt genotypes compared
to their non-Bt counter parts. In general, Bt cotton hybrids are physiologically more
efficient than non-Bt counterparts.