PRESOWING SEED TREATMENTS TO ENHANCE SUPERSWEET SWEET CORN SEED AND SEEDLING QUALITY

Poor emergence and low seedling vigor are characteristics of many supe rsweet sweet corn (Zea mays L.) cultivars carrying the shrunken-2 (sh2 ) gene. Four sh2 sweet corn cultivar seeds ['How Sweet It Is' (HSII), 'Crisp N' Sweet 711' (CNS-711), 'Sweet Belle' (SB), and 'Dazzle' (DZ)] were solid-matrix-primed (SMP), SMP with sodium hypochlorite (SMP(cl) ), treated with a fungicide combination (F) (Imazalil + Captan + Apron + Thiram), or primed with the aforementioned fungicides (SMP(f)). The seed treatments were tested in the laboratory and the field. Seed imb ibition and leachate electrical conductivity were lower in SMP seeds t han in nonprimed seeds. In the field, emergence percentage and rate of CNS-711 and SB (high-vigor seeds) were not improved by the seed treat ments compared to the nontreated seeds. Emergence percentage and rate of HSII and DZ (considered low-vigor seeds) were improved as a result of SMP(cl), SMP(f), or F treatments compared to nonprimed seeds. Compa red to the F treatment, the SMP(cl) presowing treatment increased DZ s eedling emergence rate and percentage. The combined SMP and seed disin fection via NaOCl seems to be a promising fungicide seed-treatment sub stitute that improves the stand establishment and seedling vigor of sh 2 sweet corn cultivars. Chemical names used: [2-(2,4-dichlorophenyl)-2 -(2-propenyloxy)ethyl]-1H imidazole (Imazalil); chloromethyl)thio]-4-c yclohexene-1,2-dicarboximide (Captan); N-(2,6-dimethylphenyl)-N-(metho xyacetyl)alanine methyl ester (Apron); tetramethylthiuram disulfide (T hiram).