<p>The research of the durability of maize high-yielding variety resistance towards downy meldew from the Peronosclerospora maydis species aims to discover the durability of maize high-yielding variety resistance towards Downy mildew P. maydis. This research was conducted in Kediri, East Java particularly in downy mildew endemic area, from pathogen which causes P. maydis. There are 10 new high-yielding varieties that were tested. The experiment was compiled in group plan with 3 rehearsals. Every patch size are 5 x 4, the plant space is 75 x 20 cm, the population each patch is 90 plants. At the age of 10 days after the cultivation, the plants were supplied with mixed basic fertilizer from urea, ZA, SP-36, and KCI in which their amount are 100 kg, 100 kg, and 100 kg/ha. At the second and third fertilization on the 30th and 45th days after the cultivation, the plants were supplied 100 kg urea/ha each fertilization period. The result show that the variety of Bima 5, HJ 21 Agritan, Bima-14 Batara dan Bisi 19 URI which previously had a high characteristic of resistance towards downy mildew performed low resistance durability or turned to be vulnerable with downy meldew infection approximately 62 % - 77,25 %. In contrast, the variety of Bima-3 Bantimurung, Bima -20 URI, Bima 15 Sayang and Lagaligo composite maize indicated higer resistence durability with downy mildew infection approximately 13,59 % - 20,39 % in vulnerability comparison (Anoman) reached 100%. The systemic influence of the characteristic of resistance durability also appeared on the production variable and weight of 1000 seeds.</p><p> </p>

Green leafhopper (GLH), Nephotettix virescens, is the most efficient vector of rice tungro virus disease. The disease is endemic in some provinces of Indonesia and commonly con-trolled using resistant varieties. Resistance of rice varieties to tungro could be classified into resistance to a virus and a vector. The history of GLH resistant varieties adoption affected the GLH adaptation in an area. The study was conducted in the period of 2009-2011 to evaluate the resistance status of five GLH resistant rice variety groups (T0-T4) using survival and transmission test. The GLH populations were collected from 15 tungro endemic provinces in Indonesia. The GLH was then reared in the greenhouse before used for the test. The degree of resistance to tungro viruses was calculated by adding the value of survival (weight x score of survival rate) and virus transmission rate (weight x score of transmission rate). The weights for survival and transmission rate were set to 40 and 60, respectively. The results showed that the rank of resistant variety groups in decreasing order of resistance were T4, T1, T2 and T3. Five variations in GLH transmission efficiency were identified, i.e. 170, 070, 050, 030 and 010. GLH populations from Bali and West Nusa Tenggara were the most efficient vector for rice tungro virus. We concluded that there were diversities in the degree of resistance among GLH resistant varieties. Variation in virus transmission efficiency (biotype) among GLH populations collected from various tungro endemic areas closely related to the history of adoption of rice varieties.

The resistance level of several national superior corn varieties to the primary disease of corn is still varied and unstable. Therefore, evaluating the resistance of hybrid corn varieties candidate to the primary disease of corn is deemed necessary as an initial step in managing the disease. This study aimed to evaluate the resistance reaction of the hybrid corn varieties candidate against the primary disease of corn. This study was conducted at two different locations. The first location was at the Agricultural Technology Research and Assessment Installation (ATRAI) of the Indonesian Cereals Research Institute in Bajeng District, Gowa Regency, South Sulawesi first, where the test for P. phillipinensis downy mildew, leaf blight, and leaf rust was conducted. The next location was at the ATRAI of Muneng of the Research Institute for Various Nuts and Tubers in Probolinggo, East Java, where the test for the P. maydis downy mildew was conducted. The tests were carried out using plants as the source of the test pathogen inoculum planted around the experimental block. The four corn genotypes tested were CHC1, CHC02, CHC3, CHC5, and CHC5. Meanwhile, the comparison varieties used were P36, Pertiwi-6, PAC339, BISI18, Anoman, and Pulut. The test results showed the two hybrid corn varieties candidate that were moderately resistant to P. philipinensis, namely CHC1 and CHC2, with attack intensities of 30.94% and 32.07%, respectively; one variety candidate resistant to P. maydis, namely CHC1 with an attack intensity of 15.92%. Meanwhile, the five hybrid corn varieties candidate, namely CHC1, CHC02, CHC3, CHC5, and CHC5, showed a moderately resistant reaction to maydis leaf blight and leaf rust with an attack intensity of 35%.

Indigenous fungi can suppress infection by pathogens and produce secondary metabolites that directly or indirectly affect plant growth. This study aimed to test indigenous fungi collected from corn plants as biological control agents and their effects on the viability and vigor of corn seeds. Purposive sampling method was used for sampling where soil samples taken from the rhizosphere zone, corn stem and leaf tissue from three locations namely Maros-South Sulawesi, Bone-South Sulawesi, Sigi-Central Sulawesi, Indonesia. Rhizospheric fungi were isolated from soil collected at the rhizosphere and rhizoplane using a serial dilution technique, while the endophytic fungi isolated from the leaves and stem tissues using surface sterilization method. The isolated fungi were cultured on a potato dextrose agar (PDA) medium. An antagonism test was performed using the dual culture method on PDA media with F. verticillioides as target pathogen. Pathogenicity test and the effect of fungi on corn seed germination was carried out using the blotter test method. Parameters observed were; necrotic symptoms on seedlings, growth potential, germination, growth rate, growth simultaneity, vigor index, germination rate, and time needed for 50% of the total germination. The effect of the isolated indigenous fungi on corn growth was carried out in-planta using seedling trays. The results of the blotter test and in-planta test were further confirmed by a physiological characteristic test. And assessing the fungi's ability to dissolve potassium, phosphate, and produce protease enzymes. A total of 89 fungal isolates were isolated and collected from various parts of the corn plant. Nineteen of the 89 fungal isolates showed inhibitory activity against F. verticillioides by ! 50% inhibition. The fungal isolates JRP 5 MRS, JRP 9 MRS, JRP 10 MRS, JRP 7 MRS, and JEDF 1B BN were selected based on the tests and showed a consistently positive effect on seed viability and vigor with a value of !90%. The isolates did not cause necrosis in corn, and had the ability to suppress the growth of pathogenic F. verticillioides by ! 50%.