The effect of two QTLs for resistance to Meloidogyne incognita in cotton on nematode egression from roots.

Autor:	da Silva MB; Formerly University of Georgia, Department of Plant Pathology, Tifton, GA 31793, currently Germains Seed Technology, Gilroy, CA 95020., Davis RF; USDA-ARS Crop Protection and Management Research Unit, Tifton, GA 31793., Nichols RL; Cotton Incorporated, Cary, NC 27513., Kumar P; USDA-ARS Crop Improvement and Protection Research Unit, Salinas, CA 93905., Chee PW; University of Georgia, Department of Crop and Soil Sciences and Institute of Plant Breeding, Genetics, and Genomics, Tifton, GA 31793.
Jazyk:	angličtina
Zdroj:	Journal of nematology [J Nematol] 2021 Jan 13; Vol. 52. Date of Electronic Publication: 2021 Jan 13 (Print Publication: 2020).
DOI:	10.21307/jofnem-2020-122
Abstrakt:	Cotton is widely grown in the southern US and Meloidogyne incognita is its most significant pathogen. The germplasm line M-120 RNR is highly resistant to M. incognita due to two resistance QTLs (quantitative trait loci), qMi-C11 and qMi-C14 . Both QTLs reduce total egg production, but the QTLs affect M. incognita development at different life stages. The QTLs do not appear to affect initial penetration of M. incognita but genotypes containing qMi-C11 had fewer nematodes in the roots 8 days after inoculation than near isolines without qMi-C11 , which may indicate M. incognita egression from roots. Three greenhouse trials were conducted using cotton isolines to determine whether qMi-C11 and qMi-C14 affect egression of M. incognita juveniles from roots. On each of the five sampling dates (4, 6, 8, 10, and 12 DAI), nematodes that egressed from roots were counted and roots were stained to count nematodes that remained in the roots. The effect of resistance QTLs on M. incognita egression from the roots differed among the trials. Nematode egression was consistently numerically greater, but inconsistently statistically different, from plants with both QTLs than from plants with neither QTL. Plants with only one QTL generally did not differ from plants with both QTLs, and the effects of qMi-C11 and qMi-C14 did not differ in any consistent way. In a separate experiment, plants with neither QTL had more eggs per egg mass than did plants with both QTLs, whereas plants with only one QTL had an intermediate number. Root gall size was measured in two trials and no consistent differences in gall size were observed. We conclude that (1) qMi-C11 and qMi-C14 do not stimulate nematode egression from cotton roots, (2) both qMi-C11 and qMi-C14 reduce M. incognita eggs/egg mass, and (3) neither qMi-C11 nor qMi-C14 affect gall size. (© 2020 Authors.)
Databáze:	MEDLINE
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