Resistance source detection against Stalk Rot (Fusarium Verticilliodes) under different seasons by two disease assessment methods

Abstract

Hundred maize genotypes along with two checks were grown in Maize and Millet Research Institute (MMRI) Sahiwal-Pakistan in autumn (2009) and spring (2010) to check severity of stalk rot (Fusarium Verticilliodes) under natural infection and artificial inoculation. The disease was recorded using SR (stalk rating) and LL (lesion length). Classification of genotypes was performed by using rank-sum analysis. Means of severity recorded on the basis of SR and LL in autumn were higher than spring under both methods of disease assessment. SR only exhibited significant results (P < 0.05) in autumn under natural infection while LL in natural infection and SR and LL in artificial inoculation showed highly significant results (P < 0.01) in both seasons. Genotype-season interaction was highly significant (P < 0.01) for both severity scale and seasons except for SR (P < 0.05) under natural infection. Means of SR for both seasons showed highly significant results (P < 0.01) under artificial inoculation. In natural infection, significant positive correlation (r = 0.90 to 0.93; P < 0.01) was noted between SR and LL while same correlation (r = 0.82 to 0.90; P < 0.01) was also studied under artificial inoculation between SR and LL under autumn and spring season respectively. Inbred lines (EL7, EL17, and Y11) showed highly resistance against stalk rot under both seasons and disease assessment methods. These highly resistance genotypes may be used as donor of resistant gene or genes in highly adaptive and productive susceptible varieties in further breeding programms.