Southern Blight (Sclerotium rolfsii Sacc.) of Cowpea: Genetic Characterization of Two Sources of Resistance

Table 1

Segregation for resistance to southern blight (Sclerotium rolfsii) in parental, F₁, F₂, and backcross populations of the cross “Carolina Cream” x “Magnolia Blackeye” (inheritance study I).

Population	Observed segregation				Expected segregation			Chi-square^c	𝑃
	Unweighted		Weighted		No. of plants		Expected ratio (R : S)
	𝑅^a	𝑆^b	𝑅	𝑆	𝑅	𝑆
Carolina Cream (P1)	58	0			58	0	1 : 0
Magnolia Blackeye (P2)	9	48			0	57	0 : 1
F1	94	19			113	0	1 : 0
F2	154	77	164	67	173	58	3 : 1	1.87	0.20–0.05
F1 x P1	199	25	218	6	224	0	1 : 0
F1 x P2	97	104	98	103	101	100	1 : 1	0.18	0.80–0.50

^a𝑅: number of resistant plants (stem lesion index ≤2); ^b𝑆: number of susceptible plants (stem lesion index ≥3); cweighted observed segregation versus expected segregation.