puccinia and wheat rust

stem , leaf and sripe rust in wheat

1. Symptoms and important characters of puccinia

2. puccinia Kingdom: Fungi Division: Basidiomycota Class: Pucciniomycetes Order: Pucciniales Family: Pucciniaceae Genus: Puccinia The genus contains about 4000 species. Puccinia is a genus of fungi. All species in this genus are obligate plant pathogens and are known as rusts. 

3. some species are autocious whereas some are heteroecious Mainly 3 species are found to be devastating wheat and other cereal crops through rust: Puccinia graminis : stem rust P. recondita : brown leaf rust P. striformis : yellow stripe rust

4. P. graminis P. graminis is an obligate parasite, polymorphic ( several forms of spores exists in its life cycle) and heteroecious rust . It affects wide range of hosts including wheat, barley, oats and rye.   P. graminis tritici involves in its life cycle two distinct alternate host plants i.e., wheat ( Triticum vulgare fam. Poacae) and Barberry ( Berberis vulgaris fam. Berberidaceae).

5. Symptoms On Wheat: The symptoms of the disease appear as large, elongated and brown pustules (uredosori) on the stem, leaf, sheath and leaf . Later on these brown pustules change into black coloured large pustules (teleutosori) Grains of the infected plants are shriveled, much lighter in weight and thus reducing the yield. The pathogen shows a balanced host parasitic relationship. Even in the severe infection, the parasite does not cause much serious damage except that the growth of the plants may be somewhat retarded and the granis may be of reduced size and of poor quality

6. On Barberry: Infection first starts on the dorsal surface of the leaf in the form of minute, dark coloured and flask shaped pycnia which appear as yellow spots. Beneath Pycnia, on the ventral surface, appear cup like projections of aecia or aecidia.

7. Puccinia graminis causes stem rust of different cereals like wheat, rye, oat etc. The isolate of wheat cannot infect oat or any other host and vice versa, which indicate their host specificity. i.e. biological specialisation. Thus P. graminis is a composite species. Based on pathogenecity, size of spores and cul­tural variability, it has been divided into different subspecies

8. All the above biological strains/forms and physiological races have the common barberry plant as their alternate i.e., secondary host. The differences they show are the graminaceous host.

9. Wheat crops of Northern and Southern region of India are largely affected by Puccinia graminis tritici. In South India (Nilgiri ranges) the disease appears in November, thereby the vegetative growth of the crop is affected much more than North India, where the disease appears in late March or thereafter when the crop is near its maturity. The rate of photosynthesis reduces greatly, thereby causing much loss in yield

10. Wheat leaf rust Wheat leaf rust  is a fungal disease that affects wheat, barley and rye stems, leaves and grains. Infections can lead up to 20% yield loss, which is exacerbated by dying leaves, which fertilize the fungus. The pathogen is :   Puccinia triticina  causes "black rust"   P. recondita  causes "brown rust"   P. striiformis  causes "yellow rust" It is the most prevalent of all the wheat rust diseases, occurring in most wheat growing regions. It causes serious epidemics in North America, Mexico and South America and is a devastating seasonal disease in India. All three types of  Puccinia  are heteroecious 

11. Symptoms   Small brown pustules develop on the leaf blades in a random scatter distribution. They may group into patches in serious cases. Onset of the disease is slow but accelerated in temperatures above 15 °C, making it a disease of the mature cereal plant in summer, usually too late to cause significant damage in temperate areas. On barberry leaf the disease appears as powdery yellow spots with aecia being dispersed from the underside of the leaf Losses of between 5 and 20% are normal but may reach 50% in severe cases.  Symptoms can range in severity from barely aesthetic to completely overrun on the leaf surface .

12. yellow stripe rust " Yellow rust" takes its name from the appearance of yellow- colored stripes produced parallel along the venations of each leaf blade. These yellow stripes are actually characteristic of  uredinia  that produce yellow colored   urediniospores

13. Symptoms stunted and weakened plants shriveled grains fewer spikes loss in number of grains per spike and grain weight. Losses can be 50%, but in severe situations 100% is vulnerable. In countries where wheat is grown in winters or at high elevations, yellow rust is a common threat, but not more significant than wheat leaf rust and stem rust, which are continuous threats in all wheat-growing countries.

14. References Wikipedia https://www.researchgate.net https://www.ncbi.nlm.nih.gov http://www.biologydiscussion.com/fungi/puccinia-graminis

15. Thank you Presented by : Naincy Sharma Id no. 2017002056