Nitrogen:

• Research trials on early sown (in the month of March) Bt cotton revealed that 400 kg N ha-1 was found to be appropriate for realizing economic yield.
• In normal season planting, 150-200 kg N per hectare should be applied in split doses and fertilizer application should be completed by the time the crop makes canopy or by mid-August. Excessive use of nitrogen does not improve the yield but attracts the pests and delays the crop maturity.
• The crop showing deficiency of nitrogen late in the season may be sprayed with 3% urea solution (3 kg urea/100 lit water).
• Fertigation (fertilizer application with irrigation water) of nitrogenous fertilizers is also a useful method to apply nitrogen during cropping season in leveled fields.



Phosphorus:

• In soils showing phosphorus less than 10 ppm, use 50 kg P2O5 per hectare at the time of planting. Band placement or mixing of phosphate fertilizer with farmyard manure in 1:2 ratios improves its efficiency.
• Experiments have shown that fertigation of P (application along with irrigation water) improved phosphorus use efficiency and 14% higher seed cotton yield over P application by broadcast method.
• Moreover, split applications (2 or 3) of phosphorus in comparison to full dose, applied at seed bed preparation, were found to be superior in maintaining higher soil-P availability, P use efficiency and 9% more seed cotton yield.
• Increased application of phosphorus @ 100 kg P2O5 ha-1 mitigated the adverse effects of water stress and improved seed cotton yield over recommended dose (50 kg P2O5 ha-1) applied under normal irrigation (no stress).

Potassium:

• Use 50 kg K2O per hectare at planting, to soils showing available potassium less than 125 mg kg-1 soil or soils where canal irrigation is not possible.
• Early sown transgenic cotton responded more positively to application of potassium in two splits in comparison to full dose of K applied at pre-plant. Foliar application of K provided additional benefits in terms of yield over non-sprayed plots.
• Potassium fertilizer application to conventional cotton crop through soil @ 50 kg K2O ha-1 along with four foliar sprays of 2% KNO3 produced similar yield as obtained with 100 kg K2O ha-1 without any foliar spray.

Sulphur and Farm Yard Manure:

• Studies revealed that incorporation of 25 ton FYM along with 12.5 kg elemental sulphur ha-1 provided economical seed cotton production and improved oil content of cotton seed.

Micronutrients:

• Alkaline calcareous soils of Pakistan limit the availability of soil applied micronutrients to cotton crop. The research revealed that foliar application of micronutrients i.e. zinc and boron was more efficient and economical than their incorporation into the soil.
• A total of three foliar applications of B and Zn at fruiting phase @ 0.05% solution proved to be more economical and productive in comparison to soil application.
• Addition of 2% urea with B and Zn foliar spray solution further improved nutrient absorption and seed cotton yield.

Soil health improvement:

• Alternate sources of fertilizers like FYM, humic acid; seed inoculants and growth regulators can help in improving yield and cost benefit ratio in cotton crop.
• Addition of poultry broiler litter @ 5 t ha-1 along with half of the recommended dose of NPK (75N, 25 P2O5, 25 K2O kg ha-1) produced the maximum seed cotton yield with a VCR of 6.7 and improvement in soil health.

Screening of cotton genotypes for thermal stress tolerance:

• Out of 112 cotton genotypes screened during the last 10 years, 19 genotypes were categorized as heat tolerant and approved by Punjab Seed Council, on the basis of heat tolerance data provided by the section. The detail is given below.

Sr. #	Variety	Origin	Year of approval
1	CIM-499	Breeding Section, CCRI, Multan	2003
2	CIM-506	Breeding Section, CCRI, Multan	2004
3	CIM-496	Breeding Section, CCRI, Multan	2005
4	CIM-534	Breeding Section, CCRI, Multan	2006
5	CIM-554	Breeding Section, CCRI, Multan	2009
6	CIM-573	Breeding Section, CCRI, Multan	2012
7	Bt.CIM-598	Breeding Section, CCRI, Multan	2012
8	Bt.CIM-599	Breeding Section, CCRI, Multan	2013
9	Bt.CIM-602	Breeding Section, CCRI, Multan	2013
10	NIAB-777	Nuclear Institute for Agriculture, Faisalabad	2009
11	NIAB-852	Nuclear Institute for Agriculture, Faisalabad	2012
12	BH-167	Cotton Research Station, Bahawalpur	2012
13	SLH-317	Cotton Research Station, Sahiwal	2012
14	MNH-886	Cotton Research Station, Multan	2013
15	NIAB-112	Nuclear Institute for Agriculture, Faisalabad	2013
16	*CIM-600	Breeding Section, CCRI, Multan	2015
17	Cyto-124	Cytogenetic Section, CCRI, Multan	2015
18	*Cyto-177	Cytogenetic Section, CCRI, Multan	2015
19	*NIAB-2008	Nuclear Institute for Agriculture, Faisalabad	2015

Screening of varieties for water stress tolerance:

• A total of 35 genotypes have been screened for water stress tolerance during the last 10 years, out of which 10 varieties were found to be tolerant and approved by Punjab Seed Council.
• Following water stress tolerant varieties CIM-496, CIM-506, CIM-573, CIM-554, Bt.CIM-602, Bt.CIM-608 (2013), Bt.CIM-598, Bt.CIM-599, BH-167, Bt.BH-178 (2013) and BH-184* have been approved by Punjab Seed Council. The data on drought tolerance parameters were provided by the Physiology/Chemistry Section.

• Seed priming and subsequent foliar sprays of proline demonstrated its advantage over other treatments by improving the seed cotton production per unit area and also the seed health and quality parameters of cotton seed.
• Seed physiology studies revealed that appropriate nutrition (NPK, B, Zn) have positive correlations with seed index and germination; crude protein and oil contents. Seed health and germination is negatively correlated with CLCuV, pest infestation and free fatty acids in cotton seed oil.