Yield and quality of early potato cultivars in relation to the use of glufosinate-ammonium as desiccant

BACKGROUND: Glufosinate-ammonium (GA) is used for chemical vine killing of potato crop before harvest. Over two years we tested the effect of GA, applied at 0.48 kg ha-1 of active ingredient, on desiccation of haulms, yield and some qualitative traits of tubers of three cultivars of early potatoes, a typical crop of southern Italy and large areas of the Mediterranean countries. RESULTS: Seven days after treatment desiccation reached 90% of leaves for all cultivars. At harvest, the highest desiccation percentage of haulms was 85% in Spunta. The desiccant did not affect yield in either year during which the analysis was carried out, but it increased the percentage of tubers in the range of 35-70 mm in diameter. In the first year, the treatment decreased dry matter and vitamin C content and increased free sugar concentration in tubers. In the second year, no negative effects on the nutritional traits were observed. Strong differences were found on yield and quality between the two years as a result of the different climatic conditions. CONCLUSION: In the two experiments GA had no influence on yield, but increased the percentage of potato tubers in the 35-70 mm range. From a qualitative standpoint in 2004 the chemical vine-killing treatment had some negative effects (decreased dry matter and vitamin C content, increased free sugar concentrations), whereas no such negative effects were observed in 2005. Copyright © 2009 Society of Chemical Industry