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

Table 2

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

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
Brown Crowder (P1)	51	2			53	0	1 : 0
Magnolia Blackeye (P2)	29	25			0	54	0 : 1
F1	78	11			89	0	1 : 0
F2	192	35	178	49	170	57	3 : 1	1.50	0.50–0.20
F1 x P1	172	30	188	14	202	0	1 : 0
F1 x P2	117	61	80	98	89	89	1 : 1	1.82	0.20–0.05

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