Screening for tolerance to anthracnose (Colletotrichum gloeosporioides) of shallot (Allium ascalonicum) genotypes

I.M. Hidayat, I. Sulastrini
Screening of nine genotypes of shallot collected from shallot production in west, central and east Java was conducted by subjecting those genotypes to artificial inoculation with a selected virulent isolate of Colletotrichum gloeosporioides in the screen house and natural infection in the field of the Experimental Station, Indonesian Vegetable Research Institute (IVegRI), from March 2012 to April 2013. Seed bulbs were planted in the screen house, 20 bulbs per tray, with two replications per genotype, and maintained under humid growing conditions. At the 3-5 leaf stage, plants were sprayed with 1.0-1.2×106 spores mL‑1 of the selected isolate of C. gloeosporioides. Assessment of lesion development was taken at 1-21 days after inoculation. Screening in the field was conducted during the rainy season. Each genotype was planted in the field, 200 plants per plot, with three replications each with fungicide and no fungicide application. Observation was made on lesion initiation and development at 3-8 weeks after planting, twice a week. Results indicated that the isolate of C. gloeosporioides collected from a shallot production center in central Java (Brebes) was the most effective to trigger symptoms on shallot. This isolate was used in screening for resistance to anthracnose. Based on yield from tests with and without fungicide, genotypes Sumenep, Bali Karet and Maja performed with a degree of resistance equal to tolerance to the isolate of C. gloeosporioides in the screen house with artificial inoculation, as well as with natural infection in the field. Percentage of inhibition of no fungicide application and AUDPC of both applications supported the degree of tolerance of those genotypes.
Hidayat, I.M. and Sulastrini, I. (2016). Screening for tolerance to anthracnose (Colletotrichum gloeosporioides) of shallot (Allium ascalonicum) genotypes. Acta Hortic. 1127, 89-96
DOI: 10.17660/ActaHortic.2016.1127.16
inhibition, AUDPC, degree of tolerance, lesion, Sumenep

Acta Horticulturae