Effect of two biological control agents and calcium chloride on controlling wheat leaf rust and their efficacies on grain and flour qualities [electronic resource].

Includes reference

Leaf rust, caused by Puccinia triticina, has been recognized as the main and widespread disease of wheat in the growing areas of this crop. In the present study, to set up new effective and eco-compatible control methods against the pathogen, the activity of two biological control agents (Bacillus subtilis and Trichoderma harzianum) were tested on two bread wheat cultivars at Al-Nubariya and Kafr El-Hamam Agricultural Research Stations. The two biological control agents were tested alone or in combination with Calciven, as a mineral salt. Greenhouse investigations showed that the most desirable effects on incubation and latent periods, infection type and number of pustules/leaf were improved by treating wheat seedlings with the combinations between biological control agents and Calciven (calcium chloride), with favorability to T. harzianum. Results revealed that Calciven alone or in combination with biological control agents showed the greatest effects on rust severity and area under disease progress curve (AUDPC) values, with a positive impact on yield components. Combination between T. harzianum and Calciven, at Al-Nubariya location, gave the lowest value of rust severity for Gemmiza-7 and Gemmiza-11 with the subsequent lowest value of AUDPC for both studied cultivars. Combination between T. harzianum and Calciven, at Kafr El-Hamam location, gave the highest values of 1000-kernel weight for Gemmiza-7 and Gemmiza-11 with the subsequent highest values of yield/plot for both studied cultivars. The efficiency of the studied treatments on grain and flour characteristics was evaluated on samples which obtained from Kafr El-Haman location. Technological studies were assessed in terms of grain test weight (p/B), percentages of protein content, moisture, ash, flour extraction, wet and dry glutens as well as zeleny (ml), falling number (s). Generally, the studied treatments improved the qualities of wheat grains and flour. The highest percentages of wet and dry glutens were recorded by treating Gemmiza-11 with the combination between T. harzianum and Calciven. The effects of different treatments on the curvilinearity of the relations between rust severity and grain test weight and protein content were performed. The obtained curves indicated that grain test weight as well as grain protein content can be related to rust severity. Relation between rust severity and grain protein content recorded the highest correlation coefficient (0.973), for Gemmiza-7. Collectively and in view of the seriousness of wheat leaf rust, as well as the necessity to improve the quality of wheat, the present study is helpful for further developing integrated biological control approaches for managing leaf rust of wheat.

Summary in arabic.

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