Table 3.

Actual PSII efficiency (ϕ_{PS II}), maximal efficiency of PSII photochemistry (F_v/F_m) and non-photochemical quenching (NPQ) in the subtending leaf during cotton boll development at different fruiting branch nodes (FBN) during 2009 and 2011.

Cultivars	FBN	Days post-anthesis (d)
		2009			2011
		17	31	45	17	31	45
ϕPS II
Kemian 1	FB10–11	0.64 a	0.57 a	0.54 a	0.69 b	0.65 a	0.52 a
	FB2–3	0.68 a	0.62 a	0.56 a	0.73 a	0.66 a	0.53 a
Sumian 15	FB10–11	0.52 b	0.53 b	0.51 a	0.68 b	0.61 a	0.45 a
	FB2–3	0.67 a	0.64 a	0.52 a	0.71 a	0.63 a	0.47 a
Fv/Fm
Kemian 1	FB10–11	0.82 a	0.78 a	0.71 a	0.76 a	0.75 a	0.65 a
	FB2–3	0.84 a	0.81 a	0.72 a	0.79 a	0.76 a	0.63 a
Sumian 15	FB10–11	0.80 a	0.73 a	0.69 a	0.74 a	0.72 a	0.63 a
	FB2–3	0.81 a	0.74 a	0.71 a	0.77 a	0.73 a	0.67 a
NPQ
Kemian 1	FB10–11	0.81 a	0.84 a	0.91 a	0.75 a	0.86 a	0.89 a
	FB2–3	0.78 a	0.82 a	0.90 a	0.73 a	0.85 a	0.86 b
Sumian 15	FB10–11	0.74 a	0.81 a	0.89 a	0.77 a	0.83 a	0.87 a
	FB2–3	0.73 a	0.80 a	0.86 b	0.73 b	0.82 a	0.84 b

Values followed by a different letter within the same column are significantly different at P = 0.05 probability level.