Responses of different potato late blight control technologhies to the use of noninvasive methods

Abstract

The present study was conducted to investigate potato late blight influence on leaf chlorophyll level. Field experiments were carried out in the years 2014-2016 to the National Institute of Research and Development for Potato and Sugar Beet – Brasov, Romania. It was used a complet randomized block design with four replicates, two planting distance between plants on row and different fungicides. At measurements in early July in 2014 and 2016, the varieties had close SPAD values (SPAD 39.5 and 40.1 for Roclas variety, SPAD 41.9 and 37.5 for Christian variety), which were lower at all varieties compared to the values measured in 2015, at which the SPAD average values were 47.8 at Riviera, 48.0 at Roclas and 49.4 at Christian. In 2014, following the measurements made to Roclas and Christian varieties, there was a close correlation between the SPAD values and the number (0,752 *), respectively the weight of the tubers at nest (0,882 **), while the correlation was negative between the SPAD values and the weight of the aerial part of plants (-0,722) *. In this year correlations between SPAD average values, total yield and commercial one were insignificant. The only year of the experimental cycle in which SPAD average values from variants correlated significantly was 2016, the year leading to the highest SPAD correlation coefficients - totalyield (0,706 *) and SPAD - commercial yield (0,656 *)