abstracts - INCDCSZ Brasov

STABILITY OF RESISTANCE TO PHYTOPHTHORA INFESTANS IN POTATO
CULTIVARS EVALUATED IN THE FIELD AND LABORATORY EXPERIMENTS.
Tatarowska B.,
Plant Breeding and Acclimatization Institute, Młochów Research Center, 05-832 Młochów, Platanowa
str.19, Poland
btatarowska@poczta.ihar.edu.pl
Stability of resistance across locations and over time is difficult to study because it requires
historical data so that inferences about stability may be drawn over a significant period. A genotype is
considered to be stable resistant, if among-environment variance of resistance is small. Becker and
Léon (1988) referred to this stability as a static or biological. A stable genotype possesses an
unchanged performance regardless of any variation of the environmental conditions. Analyses of
genotype by environment interactions and estimation of biological stability have been studied during
the last decades and several methods were proposed for its estimation.
In this study, genotype by environment (G × E) interactions and biological stability of resistance to
Phytophthora infestans were analyzed for 22 potato cultivars, using multi and one-dimensional
statistical methods. The Sergen program developed by Caliński et. al. (1998) was applied for these
analyses. The potato cultivars were tested in four experiments in Central and Southeastern parts of
Poland over four years.
The cultivars were planted at each location at the beginning of April and were cultivated
without protection against late blight. Tested cultivars were exposed to the natural infection with P.
infestans. Each cultivar was grown on 6-hill plots in two replications surrounded by susceptible
cultivar, which served as infector. The development of late blight in foliage was evaluated weekly
using 9 grade scale (where 9 = resistant). The relative area under the disease progress curve (rAUDPC)
for each cultivar was calculated after field observations.
The analysis of variance of diseases data (rAUDPC) for 22 cultivars in 13 environments
indicated significant (P