| Abstract |
The 1975-76 crop season was marked as the best cereal production year in Algeria since 1909 (the date from which data is kept). The rain distribution in almost all the regions was excellent from seeding to mid dough stage, except parts of western Algeria, where drought during March, April and an early sirocco did considerable damage to the cereals. From then on there were unusually heavy rains in almost all regions causing considerable damage to the cereals. Barley was the worst affected. Official estimates are that the production during the 1975-76 season was 29 million quintals or close to 10 million quintals more than the national average. The prolonged mild winter season helped the development of stripe rust into epidemic proportion in the eastern regions of Algeria. The spectrum of virulence was highly limited. However, the predominant variety Siete Cerros was susceptible. Based on the yield trial results of the past four years it is estimated that the average loss of Siete Cerros due to stripe rust was about 18% in the eastern regions of Algeria (TABLE A. l. ). Stem rust was also present in almost all regions. However, the prolonged cooler conditions did not permit it to develop into epidemic proportions. The virulence pattern based on the observations of the regional disease trap nursery suggests that, of the single genes only Sr.11 was effective. Almost all the combinations of Sr factors also held the resistance. Most of the bread wheats in cultivation except Mahon Demias held resistance to the prevailing races. However almost all the commercial durums were susceptible. Derivatives of Langdon, Leeds and Wells like Mexicali and Flamingo were holding resistance to the prevailing races. An analysis of the race spectrum during the 1974-75 season shows that races lSB, 9, 24, 19 and 17 were present. Since race 11 and its subraces are reported in all the neighboring countries this race is also likely in Algeria. There was very little leaf rust during the 197 5-76 season. Of the different LR lines only Th 6 x Aniversario, Thew and Fn x Mida/Kll 7A showed a susceptible reaction showing that the virulence during the year was highly limited. Septoria was of minor importance al though humidity was present in abundance throughout the crop season. Lack of prolonged cloudy days and relatively warm winter season can be the factors which kept Septoria from developing into a major disease. |
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