CHARACTERIZATION OF AVENAE PATHOTYPES FROM SPAIN

BY

AGUSTIN SANCHEZ and Ma CRISTINA ZANCADA Instituto de Edafologia y Biologia Vegetal (C.S.I.C.), Madrid, Spain

Populations of Heteroderaavenae from 12 infested sites from different geographical areas of con- tinental Spain are characterized by the International test assortment for resistance to H. avenae. The 12 populations can be grouped in three new and different pathotypes. These three pathotypes also differ from the ten previously reported in the literature. The new pathotypes are: Ha22 - populations 1-6 from Teruel, Ha71 - populations 7-11from Toledo and Ha81 - population 12 from Sevilla. Keywords:Cereal cyst , pathotypes, , , , .

Heterodera avenae Wollenweber has been recorded from Spain by a number of investigators (Romero et al., 1973; Sanchez et al., 1983, 1985) and detailed morphological observations are available (Romero, 1977, 1980 & 1982). The present work was done to characterize the pathotypes in some Spanish popula- tions of H. avenae. Andersen (1959) first recorded the existence of different pathotypes of the cereal cyst nematode, Heterodera avenae, in Denmark. Since then, a total of ten pathotypes have been detected which according to Andersen & Andersen (1982) can be placed in three groups: group 1 includes Hall from Denmark (Andersen, 1959 & 1961) and France (Rivoal, 1977); Ha21 from Holland (Kort et al., 1964); Ha3l found in India (Mathur et al., 1974); Ha41 reported from France by Rivoal (1977); Ha51 in Holland (Kort et al., 1964) and in Norway (Stoen, 1971); and Ha6l in Holland and Germany by Lücke (1976). Group 2 includes only pathotype Hal2 detected in Denmark by Andersen (1959 & 1961) and in France by Rivoal (1977). The following pathotypes are in group 3 : Hal3 found in Australia (Brown & Meagher, 1970; O'Brien & Fisher, 1979); Ha23 detected by Cook (1975 & 1982) and Ha33 found by Jakobsen (1981), both from England and Denmark. The last two are not widely distributed. This paper reports the results obtained by testing 12 populations of H. avenae collected from different geographical areas of continental Spain.

MATERIALS AND METHODS

Pathotypes of H. avenae were distinguished by testing for virulence against a number of discriminating cereal cultivars. 56

Seed samples of the 25 cultivars used in testing for resistance to H. avenae were obtained from Denmark (Table I). These cultivars have been recom- mended by Nielsen (1972) for characterizing H. avenae pathotypes. Sampling was planned in such a way that cysts were extracted from soil col- lected from 12 infested sites in three different geographical areas of continental Spain: North-East (sites 1-6 in province of Teruel), Central Plateau (sites 7-111 in province of Toledo) and South-West (site 12 in province of Sevilla). Seeds of the test cultivars were germinated in a moist chamber. Each test cultivar was planted in a 1.5 1 plastic bottle and infested with cysts of H. avenae placed inside a small 250 itm mesh nylon bag. Each of these bags contained 25 cysts. However for testing cultivars 40 cysts were used. The soil for the experiments was collected from the same 12 sites, sterilized by dry heat in a Pasteur stove at 160°C and fertilized with 1 g of granular NPK when required. Four replicates of each cultivar were maintained. The experiments were done outdoors from November 1981 to July 1985; those with oats were repeated for two consecutive years.

RESULTS

Table I shows the reaction of the different cereal cultivars to the 12 popula- tions tested. In barley, cultivars Varde, Emir, Martin 403-2 and Dalmatische were susceptible to all 12 populations of H. avenae; however, Siri, Morocco and P. 31 322-1 were resistant to all of them; Ortolan was susceptible to populations 1-6 (Teruel) and resistant to the remaining populations; finally, Bajo Aragon was resistant to populations 1-6 and 12 and susceptible to populations 7-111 (Toledo). All the oat cultivars were resistant to the 12 populations of H. avenae. The behaviour of the wheat cultivars was as follows: Capa and Iskamish K- 2-dark were susceptible to all populations and 63/1-7-15-12 (Loros) and Psathias resistant to all of them. Iskamish K-2-light was susceptible to popula- tions 1-11 (Teruel and Toledo) and resistant to population 12 (Sevilla) and Aus 10894 susceptible to populations 1-6 (Teruel) but resistant to 7-12 (Toledo and Sevilla). Both rye cultivars were susceptible to all nematode populations, although Petkus Spring was always more susceptible than Rogo. Virulence of the populations 1-6 from Teruel to Ortolan barley and Aus 10894 wheat makes them different from populations 7-11 from Toledo and population 12 from Sevilla. Likewise, the five populations from Toledo (7-11) were virulent to Bajo Aragon barley, indicating their difference from populations 1-6 from Teruel and 12 from Sevilla; the latter also differs from both groups in being avirulent to Iskamish K-2-light wheat.