Publicación y repositorios

1_{Institut National de la Protection des Végétaux, EI Harrach, Alger, Algeria.} 2_Institut National Agronomique, El Harrach, Alger, Algeria. 3_{Correspondence:} [email protected]

SUMMARY

A study of the influence of soil temperature on hatching of Heterodera avenae over two successive years revealed emergence of 21, 37, 27, 39 and 42% of juveniles for populations of Djendel (Aïn Defla), Oued Fodda (Chlef), Dahmouni (Tiaret), Amari (Tissemsilt) and Oued Smar (Algiers), respectively. Emergence occurred during the winter period, starting in October or November and ending in April. The data indicate that temperatures from 10 to 20C are suitable for hatching, with and optimum of 14.5C for the populations studied. These populations have hatching patterns typical of the southern European ecotype of H. avenae, with winter emergence of juveniles and a summer-autumn diapause.

INTRODUCTION

The influence of soil temperature on the hatching of second stage juveniles (J2) of Heterodera avenae and their emergence cycles have been the subject of investigation under laboratory and field conditions (Meagher 1970, Rivoal 1978, 1983, Mokabli et al. 2001).

In Canada and in the countries of northern Europe, the emergence of juveniles starts when the temperatures reach 15 to 20C in the spring (Fushtey and Johnson 1966). By contrast, in countries where the climate is hot in summer, the hatching begins by decreasing soil temperatures in the autumn. In India, the optimal temperature for the emergence was estimated by Bhati and Malhan (cited in Zancada and Sanchez 1989) between 15 and 20C. In South Australia, Banyer and Fisher (1971) have determined that a temperature of 15C stimulated hatch.

In our investigations, we have used populations of H. avenae from diverse geographic origins to evaluate the effect of soil temperature on the hatching process

*_{Smaha D, Hamroun O, Mokabli A (2009) Soil temperature on hatching of Heterodera avenae}

in Algeria. In ‘Cereal cyst nematodes: status, research and outlook.’ (Eds IT Riley, JM Nicol, AA Dababat) pp. 130-133. (CIMMYT: Ankara, Turkey)

(release and arrest) of J2 emergence. Percentages of J2 hatching per cyst and year were calculated to evaluate the numbers of hatching cycles.

METHODS

Populations of H. avenae from five locations in Algeria were examined (Table 1). The study was carried out in two successive years (2005/06 and 2006/07) at the Institut National de la Protection des Végétaux experimental station.

For each population, 20 cysts were individually placed in tubes with 1 ml of distilled water. Tubes were placed in a hole dug at 30 cm depth in the soil and covered with sod. The soil temperature was recorded with a thermometer placed vertically just close to the tubes containing cysts. The temperatures as daily averages were obtained, which allowed subsequent calculations of weekly averages. The J2 emergence was counted each week.

RESULTS

First emergence of J2 was from November to February for the five H. avenae populations in the first year and from October to January in the second year (Table 2). The commencement of the first cycle of emergence occurred at lower temperatures than the second. Hatching was finished by the end of April each year when soil temperature reached 17C.

At the end of the two hatching cycles, proportion of J2 hatch was 42, 21, 37, 39 and 27% for the populations from Oued Smar, Djendel, Oued Fodda, Amari and Dahmouni (north to south), respectively. For each population, emergence occurred systematically in the winter period with a beginning in October or November and finishing at the end of April (Figure 1).

DISCUSSION

All populations of H. avenae studied showed hatching cycles similar to that of other populations from Mediterranean climates. Emergence began in October or

Table 1. Location (no

Algeria, and range an locations.

orth to south) of po nd mean of soil tem

opulation mperature ns of He es (C) fo eteroder or Janua ra avena ary and J ae samp July fo pled in or these

Town (Province) Latitude JJanuary July

Town (Province) Latitude

Max Min Mean Max Min Mean

Oued Smar (Alger) 36°43’ N 16.2 5.6 10.9 31.2 24.9 18.7

Djendel (Aïn Defla) 36°16’ N 13.6 5.3 9.4 33.5 21.4 27.4

Oued Fodda (Chlef) 36°11’ N 15.5 5.9 10.7 40.2 23.7 31.9

Amari (Tissemsilt) 35°37 N 11.9 2.2 7.0 36.4 20.3 28.3

November, when the soil temperature fell below 20.3C. The J2 cease to hatch in April when the soil temperature reached 17C again.

The Algerian populations were similar to their counterparts of southern Italy (Greco 1981, Greco and Brandonisio 1987), Spain (Romero and Valdeolivas 1990, Valdeolivas et al. 1991) and South Australia (Meagher 1970), where hatching occurred during the periods of lower temperatures. In Algeria, hatching was triggered by declining temperature, while increase of temperature (up to 17C) caused cessation of the hatching cycle for all populations tested.

The work confirmed that Algerian populations of H. avenae from the five locations belong to the Mediterranean ecotype characterised by winter hatching activity.

Figure 1. Proportion of hatch of five populations of Heterodera avenae collected in

Algeria (north to south) buried at 30 cm in field soil and monitored over two successive years; 2005/06 (bottom), 2006/07 (middle) and unhatched (top).

0 25 50 75 100

Oued Samar Djendel Oued Fodda Amari Dahmouni

Hatch/Unhatched (%) Table 2. First em locations (north t mergence of juve to south) in Alger eniles of Heterod ria buried at 30 cm

dera avenae from m in field soil.

m cyst from five

Year Source location First emergence

(week - month) J2/cyst Soil temperature

Oued Smar 2 - Nov 2.4 18.4

Djendel 2 - Jan 0.4 12.3

2005/06 Oued Fodda 1 - Dec 1.9 14.8

Amari 4 - Nov 1.1 16.5

Dahmouni 3 - Feb 5.3 11.3

Oued Smar 2 - Oct 0.9 20.1

Djendel 4 - Oct 0.9 20.3

2006/07 Oued Fodda 2 - Nov 1.1 18.1

Amari 4 - Oct 0.8 20.3

Furthermore, we observed that the proportion of unhatched eggs was considerable (about 60-80%) at the end of the two-year experiment, which indicates cohort of J2 which are able to hatch each year as previously noted by Meagher (1970) in Australia and Rivoal (1983) in France.

In Algeria, variation of the tolerance of cereal cultivars to H. avenae can be explained, in part, by the biology of the nematode. Indeed, durum and bread wheat sown in late autumn are more vulnerable to nematode attack, as their early vegetation coincides exactly with the beginning of J2 emergence. Such vulnerability of durum wheat to H. avenae infestations was observed also in France. In contrast, in northern Europe, spring sown cereals, such as oat or maize, are more vulnerable to this nematode because their growing period coincides with the spring activity of the northern ecotype (Rivoal and Ireholm 1990).

REFERENCES

Banyer RJ, Fisher JM (1971) Effect of temperature on hatching of eggs of Heterodera avenae. Nematologica 17, 519-534.

Fushtey SG, Johnson PW (1966) The biology of the oat cyst nematode, Heterodera avenae in Canada. I. The effect of temperature on the hatchability of cysts and emergence of larvae. Nematologica 12, 313-320.

Greco N (1981) Hatching of Heterodera avenae. Nematologica 27, 366-371.

Greco N, Brandonisio A (1987) Investigations on Heterodera avenae in Italy. Nematologia Mediterránea 15, 225-234.

Meagher JW (1970) Seasonal fluctuations in numbers of larvae of the cereal cyst nematode (Heterodera avenae), Pratylenchus minyus and Tylenchorhynchus brevidens in soil. Nematologica 16, 333-347.

Mokabli A, Valette S, Gauthier JP, Rivoal R (2001) Influence of temperature on the hatch of Heterodera avenae Woll. populations from Algeria. Nematology 3, 171-178.

Rivoal R (1978) Biologie d'Heterodera avenae Wollenweber en France. I. Différences dans les cycles d'éclosion et de développement des deux races Fr1 et Fr4. Revue de Nématologie 1, 171-179.

Rivoal R (1983) Biologie d’Heterodera avenae Wollenweber en France. III. Evolution des diapauses des races Fr1 et Fr4 au cours de plusieurs années consécutives: influence de la température. Revue de Nématologie 6, 157-164. Rivoal R, Ireholm A (1990) Cycles d'éclosion de trois populations d'Heterodera

avenae (Nematoda, Heteroderidae) de France et Suède: influence de la température sur l’évolution de leur diapause respective. Colloque INRA (Régulalion des cycles saisonniers cmz les inverlébrés. Dourclan, France, 20-22 Févrler 1990) 52, 171-174.

Romero MD, Valdeolivas A (1990) Bio-ecological characteristics of the cereal cyst nematode Heterodera avenae in Spain. Nematologia Mediterránea 18, 145-149. Valdeolivas A, Romero MD, Muniz M (1991) Effect of temperature on juvenile

emergence of Spanish populations of Heterodera avenae. Nematologia Mediterránea 19, 37-40.

Zancada M, Sanchez A (1988) Effect of temperature on juvenile emergence of Heterodera avenae Spanish pathotypes Ha81 and Ha22. Nematologica 34, 218-225.

PART 4 MANAGEMENT BY HOST

RESISTANCE

SUCCESS OF CEREAL CYST NEMATODE