Investigation of antixenosis resistance of 33 potato cultivars to the Colorado potato beetle, Leptinotarsa decemlineata (Col.: Chrysomelidae)

The Colorado potato beetle, Leptinotarsa decemlineata (Say), is a serious pest of potato, Solanum tuberosum L. worldwidely. One of the methods used for controlling of it is deployment of resistant cultivars. Field experiments were conducted to evaluate the antixenosis resistance in 33 potato cultivars to this pest during 2007 - 2009. Research method in 2007 was similar to 2008 and was different from 2009. In a field choice test, the numbers of attracted beetles to the cultivars were determined as antixenosis index. Numbers of attracted beetles to the cultivars and numbers of egg masses on them were used as antixenosis indices during 2009. Cluster analysis of cultivars was performed with MINITAB15 statistical software using UPGMA procedure based on Euclidean distance. Combined analysis of variance of choice test data in 2007 and 2008 showed that with point of settled adult beetles on the studied cultivars, significant difference was observed between experimental years, blocks, times of counting, cultivars and reciprocal effect of cultivar × year (P < 0.0001). Mean comparison showed that cultivars Bright, Delikat, Nicola, Sinja, Carlita and Cardinal in 2007 and Cardinal, Carlita, Sinja, Elles and Romina in 2008 had the highest antixenosis resistance with the least settled adult beetles on them. Cluster analysis showed that in two first years, cultivars Cardinal, Carlita, Sinja, Bright, Raja, Nicola, Romina, Santana, Elles, Fianna and Satina with the least attracted beetles were resistance group in antixenosis index. Also, cluster analysis based on the number of attracted beetles to the cultivars and number of egg masses on the cultivars showed that cultivars Bridjet, Baltica, Cardinal, Nicola, Raja, Bright, Delikat, Carlita, Provento, Cosima, Armada, Elles and Beluga were placed in one group and had the highest antixenosis effects compared to others cultivars in 2009. Mean comparison showed that cultivars Cardinal, Carlita and Bridjet had the highest antixenosis resistance with the least settled adult beetles on them in three experimental years.