Screening of clovers for resistance to clover scorch

Clover Scorch (Jointly with Dr C.M. Francis). One thousand four hundred and seventy six legumes were screened in the field at the Denmark Research Station for susceptibility to clover scorch. They comprised 1440 subterranean clovers, eight other Trifoliums, two medics and 26 serradellas. The clovers from Australia gave interesting results. Thirty four of them were selections of Seaton Park, chosen by R.C. Rossiter and W. J. Collins on the basis of their variation. They did not differ in their reaction to clover scorch; all gave rating of 9. Twenty-six lines of Woogenellup from W.A. and 12 of Woogenellup and Morrar from N.S.W. were also tested. The Western Australian lines comprised 9 certified lines and 17 farmer samples from throughout the State (Esperance, Gairdner River, Kojanerrup, Albany and Ravensthorpe). They were tested because some farmers claimed that there appeared to be variation between lines and sources of Woogenellup in susceptibility to clover scorch; - all gave similar, high ratings at Denmark. The 12 lines of Woogenellup and Morrar also gave similar and high ratings. Sixty one per cent of the 309 cross breds gave low ratings (Table 2). Some crosses were quite unsuccessful, e.g. Midland B x Gingin, where 26 of the 27 crosses gave exceptionally high disease ratings. Others were the reverse, e.g. Dalkeith x 47308C and Dinninup x Daliak x Toodyay C where the majority proved very resistant