Fusarium wilt incidence in cotton fields and its effect on seed germination of different cultivars/varieties

Cotton fields in the surroundings of Tandojam viz. Khesano Mori, Mossa Khatian, Rahooki, Shahpur, Tando Qaiser. Villages Imam Bux Pusio, Village Jiskani, Shafqat Hussain Shah, were surveyed during April and May 2005, to estimate the Fusarium wilt disease incidence. The incidence ranged between 3.00 to 42.00%, minimum (3.00%) at Village Shafqat Hussain Shah and the maximum (42.00%) at Village Jiskani. The studies on effect of Fusarium wilt in available cotton varieties were carried out from April to September 2005. Fusarium oxysporum f.sp. vasinfectum was isolated and identified. Ten seeds of 10 commonly available cotton cultivars/varieties viz., CRIS-134, Hari dost, Malmal, NIAB-78, Rehmani, Reshmi, Shahbaz, Sindh-1, TH-10/96 and TH-57/96 were sown in earthen pots containing 2kg sandy soil followed by mixing 0.00, 0.25, 0.50, 0.75 and 1.00 petridish per pot of fresh culture. The results showed highly significant difference at P < 0.05 with reference to effect of Fusarium wilt on seed germination. Significantly minimum seed germination (0.25 to 1.00 seed/pot with 2.50 to 10.00%) was recorded in TH 10/96, TH 57/96, NIAB-78, Shahbaz, Malmal and Reshmi, 5 and 10 days after sowing at 1.00 petridish/pot. Maximum germination (6.50 seeds/pot with 65.00%) was in CRIS-134 followed by 6.25 with 62.50% in Shehbaz, 6.00 with 60.00% in Hari dost, Sindh-1, Malmal, Reshmi and NIAB-78 and 5.75 with 57.50% in TH-57/96, at 0.00 petridish/pot 10 days after sowing. Some of the varieties increased seed germination from 5 to 10 days after sowing while few remain at the same (equal) number of germinated seeds even on 5 and or on 10 days after sowing. The germination was significantly decreased over control as inoculum level increased.