Regional variation in pathogenicity of Meloidogyne incognitapopulations on sweetpotato in Kyushu Okinawa, Japan

Abstract

Regional variation in pathogenicity of Meloidogyne incognita populations on sweetpotato in Kyushu Okinawa, Japan. Zen-ichi San& and Hideaki Iwahori2To use resistant cultivars of sweetpotato effectively occurrence and distribution of pathogenic races of M incognita were examined. Five sweetpotato differential cultivars, 'Norin -1' ,'Norin-2','Tanegashimamurasaki-7','Elegant Summer' and Tred', which were selected from major Japanese sweetpotato cultivars based on resistance response to four M incognita populations with different virulence were used as differential hosts. A total of 129 M incognita populations were collected from mainly sweetpotato fields in Kyushu and Okinawa, Japan. Reproduction of the populations was assessed on the differentials based on production of egg-masses and pathogenic races were designated. Nine races, SP1 to SP9, were identified from these populations and 37.2%, 43.4% and 7.0% of the populations were, respectively, race SP1 that reproduces only on 'Norin-1', SP2 that reproduces on both 'Norin-1' and 'Norin-2', and SP4 that reproduces on four of the differential hosts but not on 'J-Red'. Region specific distribution was observed in these races. SP1 was widely distributed in Kumamoto and northern prefectures. SP2 was predominant in southern Kyushu, in both Miyazaki and Kagoshima Prefectures. SP4 was the major race in Okinawa Prefecture. Other races were detected from limited areas. Jpn. J. Nematol. 35(1), 1-12 (2005).

Development of molecular markers associated with resistance to Meloidogyne incognita by performing quantitative trait locus analysis and genome-wide association study in sweetpotato

“…In Japan, M. incognita can be found in most areas, including Kyusyu and Kanto, in which sweetpotato is cultivated 12–14 . Previous studies have reported that at least nine races of M. incognita (SP1–SP9) exist in Japan, and certain races are dominant in specific regions 15 . For example, the SP1 race is predominant in the Kumamoto, Nagasaki, and Saga Prefectures (Kyushu); in contrast, the SP4 and SP6 races are predominant in the Okinawa islands 15 and are found in the Ibaraki and Chiba Prefectures (Kanto) 16 , 17 .…”

Suppression of root-knot nematode damage to succeeding sweet potato by summer-sown cultivation of an oat variety, "Tachiibuki"

“…Each race has different pathogenicity to sweet potato cultivars bred in Japan (Sano and Iwahori, 2005). Each population was propagated for two to three months on tomato variety Pritz in pots under the greenhouse condition described below.…”

Suppression of Root-knot Nematode Damage to Next Crop by Prior Cultivation of Root-knot Nematode-resistant Sweet Potato Cultivars

“…M. incognita has many races (Sano & Iwahori 2005, Tabuchi et al 2017) that are identified based on their differing pathogenicity to several sweet potato cultivars. This has been investigated in Japanese cultivars (Sano et al 2002, Tabuchi et al 2015.…”

“…This has been investigated in Japanese cultivars (Sano et al 2002, Tabuchi et al 2015. SP2 is a dominant race in Miyazaki and Kagoshima prefectures in the southern area of Kyushu (Sano & Iwahori 2005). Some new cultivars have recently been found to exhibit a strong resistance to SP2 by evaluating the number of egg masses (Tabuchi et al 2015).…”

“…The suggested nematode management strategy must still consider several factors, such as the differences in the races of M. incognita in different areas of Japan. The dominant races in the field are only reported in Kyushu (Sano & Iwahori 2005). In Kyushu, the dominant race varies in each area.…”