Sori as potential indices for evaluating date palm germplasm against Graphiola leaf spot Thind S.K., Kaur Nirmaljit, Thatai S.K. Punjab Agricultural University Regional Fruit Research Station, Abohar-152116 Online published on 5 December, 2011. Abstract Graphiola leaf spot caused by the fungus Graphiola phoenicis (Moug.) Poit is one of the serious disease of Date palm (Phoentix dactylifera Linn). Date palm cultivars viz., Zahidi, Hallawi, Thoory, Barhee, Degletnoor, Khalsaa, Shamran, Hayani, Khadrawi and Medjool were evaluated against this disease at PAU, Regional Fruit Research Station, Abohar, India. The sori number and disease severity were taken for screening the date palm germplasm. The varieties (s) having sori number less than 4 per sq. cm were resistant (Zahidi), 4–8 moderately susceptible (Thoory, Hallawi, Barhee, Degletnoor, Khalasa, Sharman), 9–12 were susceptible (Hayani and Khasrawi) and more than 12 were highly susceptible (Medjool) to the disease. A significant positive correlation between number of sori and disease severity was established. The Prediction Model for forecasting the disease severity by using the number of sori was computed as, Y=12.06 + 4.78 X. The validity of the model was tested and predicated disease severity was significantly positively correlated with the observed disease severity. This model may be used for screening of the date germplasm against Graphiola disease and devising a judicious spray schdeule. Top Keywords Graphiola leaf spot, date palm, varietal screening. Top |