|BILAL, MUHAMMAD - University Of Agriculture - Pakistan|
|SALEEM, MUHAMMAD - University Of Agriculture - Pakistan|
|WAHID, MUHAMMAD - University Of Agriculture - Pakistan|
|SHAKEEL, AMIR - University Of Agriculture - Pakistan|
|SARWAR, MUHAMMAD - University Of Agriculture - Pakistan|
Submitted to: Journal of Plant Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/13/2017
Publication Date: 7/14/2017
Publication URL: https://handle.nal.usda.gov/10113/5763064
Citation: Bilal, M.F., Saleem, M.F., Wahid, M.A., Shakeel, A., French, A.N., Sarwar, M. 2017. Management practices to control premature senescence in bt cotton. Journal of Plant Nutrition. DOI:10.1080/01904167.2017.1310886.
Interpretive Summary: Introduction of Bt cotton has led to major benefits for commercial cotton production such as increased yield, improved lint quality and reduced pesticide costs. However, higher yields from Bt cotton substantially increases plant nutritional requirements which can lead to premature senescence. Recent research has suggested that this problem can be avoided with selective fruiting branch removal and adjustment of soil potassium levels. A two-year study (2011-2012) in Pakistan was conducted to help determine which combinations of these strategies would be the most beneficial. The best combination was removal of all squares from the first and second fruiting branches along with application of 150 kg ha-1; this practice significantly reduced premature senescence compared with 7 other less aggressive treatments. These results are important for cotton growers worldwide and especially important for those in South Asia where plant-by-plant management can be practical.
Technical Abstract: Commercial cultivation of Bt cotton produced higher boll load which led to stiff inter-organal competition for photosynthates resulting in early cessation of growth (premature senescence) due to more availability of sink and less sources. To overcome this problem field experiment was conducted during 2011 and 2012 using five treatments of plant growth manipulation viz. no fruiting branch removal (F1), removal of first fruiting branch (F2), removal of first and second fruiting branch (F3), removal of all squares from first fruiting branch (F4), removal of all squares from first and second fruiting branch (F5) and three potassium application rates viz. 50 kg ha-1 (K1), 100 kg ha-1 (K2), and 150 kg ha-1 (K3). More nodes above white flower were recorded in F5, followed by F3, while minimum were recorded in F1. Among potassium levels maximum nodes above white flower were recorded in K3 followed by K2 and K1 during both years of study. Plant height recorded at physiologically cut-out stage or at maturity stage showed that plants gained more height with removal of all squares from 1st and 2nd fruiting branches with higher potassium dose. Leaf K increased with increasing applied potassium and also with square/branch removal. So early removal of squares/fruiting branches along with higher potassium dose helped in delaying canopy senescence in Bt cotton.