Effects of Cropping System and Cowpea Variety on Symbiotic Potential and Yields of Cowpea (Vigna unguiculata L. Walp) and Pearl Millet (Pennisetum glaucum L.) in the Sudano-Sahelian Zone of Mali

Table 1

Cowpea nodules number (nodules/plant) and efficiency as affected by cropping system and cowpea variety at flower buds stage at Cinzana Agronomic Research Station, 2007 and 2008.

Treatments	Flower buds stage
	Nodules number (nodules/plant)	Efficient nodules (%)
Years
Year 1: 2007	41^a	77
Year 2: 2008	30^b	76
Cropping systems
Millet/cowpea intercropping (1 row/1 row)	47^a	78^ab
Millet/cowpea intercropping (2 hills/1 hill)	19^c	69^b
Cowpea sole crop	40^b	81^a
Cowpea varieties
V1: IT89KD-374	36	86^a
V2: CZ1-94-23-1	32	62^b
V3: CZ11-94-5C	37	80^a
Effect	𝑃 values	𝑃 values
Year (Y)	<0.01	—
Cropping system (S)	<0.01	0.03
Year × cropping system (Y × S)	0.07	—
Cowpea variety (V)	0.06	<0.01
Year × variety (Y × V)	<0.01	0.30
Cropping system × cowpea variety (S × V)	—	—
Year × cropping system × variety (Y × S × V)	0.13	—
Coefficient of variation (%)	22.78	21.21

Means followed by the same letters in the same column for each parameter are not significantly different (𝑃≤0.05), according to Duncan test.