Relation between leaf age and resistance to Cercospora leaf spot disease in sugar beet [electronic resource].

Includes reference.

This investigation was conducted during 2011/2012 season at Sakha Agricultural Research Station farm and screen-house belongs to Sugar Crops Institute. This investigation was carried out on Kawamera sugar beet cultivar to answer the question of why young Leaves of sugar beet possess a high level of resistance to Cercospora leaf spot? Under artificial inoculation by Cercospora beticola spores (50 x 103 spores / ml), disease severity, chlorophyll content, losses in both yield and sugar were evaluated in randomized complete block design experiment. Different histological and biochemical factors were measured i.e., size of stomatal apparatus, mineral contents in different leaves starting from heart leaves up to outer leaves of the plant. Results obtained revealed that percent losses of inoculated leaves was 64.15% in chlorophyll content, 52.05% and 41.74% in root and sugar yields were (respectively. Dimensions of stomatal apertures, diameter and stomata intensity showed that the young leaves were narrow and it has less number of stomata ranged from in inner leaves 115 stomata / mm2 up to 331 stomata / mm2 in outer leaves. Relative water content (RWC) was determined for sugar beet leaves, data obtained showed that young inner leaves contain less relative water content than mature outer leaves. Moreover, peroxidase activity was higher in the younger leaves than the mature one.

Summary in Arabic.

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