Rice brown spot (BS) is a chronic disease that affects millions of hectares of rice every growing season, grown by some of the most resource-poor farmers. Despite its widespread occurrence and impact, much still needs to be understood about BS. Reported yield losses in relative terms vary widely from 4 to 52 %. However, accurate, systematic estimates are lacking. BS is conventionally perceived as a secondary problem that reflects rice crops that experience physiological stresses, e.g. drought and poor soil fertility, rather than a true infectious disease. Much remains to be understood about the mechanisms leading to epidemics and crop losses. Quantitative and qualitative knowledge gaps exist in our understanding of the epidemiological processes, sources of resistance and biocontrol methods. In this review we identify several of these gaps, which if filled, could lead to a strong impact on the management of brown spot. We also use the architecture of a simulation model to position and prioritize these knowledge gaps, assess the epidemiological consequences of disease management options on

Drought and limited availability of water serve as the serious limitation for rice production in rainfed ecosystems. Among the major rainfed rice-cultivating areas, states of eastern India occupy one of the largest drought-prone ecologies in the world. Cultivating drought tolerant rice varieties can serve as the most coherent approach to ensure food security in these areas. International Rice Research Institute (IRRI), along with its national collaborators, has developed drought tolerant rice varieties possessing high yield along with desirable grain quality. One such conventionally bred line, IR74371-70-1-1, has been released with different names in the different countries: in India as Sahbhagi Dhan, in Nepal as Sukha Dhan 3, and in Bangladesh as BRRI Dhan 56. This indicates the suitability of this line to show better performance across the wide range of environments. Sahbhagi Dhan is a short duration variety that has genetic drought tolerance and is more efficient at extracting available moisture from the soil. During drought years, farmers cultivating Sahbhagi Dhan obtained the yield advantage of 0.8 to 1.6 t ha−1 over currently grown long duration as well as traditional varieties. In 2012, when the paddy crop was hit by drought, Sahbhagi Dhan revealed the yield advantage of more than a t ha−1, which reduced to 0.78 and 0.56 t ha−1 during non-drought years of 2013 and 2014, respectively. Data taken from head to head trials during 2017 showed that Sahbhagi Dhan exhibited better performance over the existing rice varieties grown by farmers even under non-drought conditions. The important feature of Sahbhagi Dhan is its evident impact under drought and no yield penalty under favorable conditions over the counterfactual varieties of the same duration. Along with better yield under drought, the important advantage of Sahbhagi Dhan is the short maturity duration of this variety. This allows the farmers to advance the succeeding crop and creates an opportunity for accommodating an additional crop under favorable rainfed ecology, thereby enhancing the cropping intensity. Since the majority of the farmers living in drought prone ecologies are socio-economically under privileged, Sahbhagi Dhan, along with other drought tolerant varieties, can serve as one of the most viable and deliverable technologies for eradicating poverty from these ecologies dependent on rainfed rice.

Flash floods leading to complete submergence of rice plants for 10-15 days is one of the major constraints for rice production, mainly in rainfed lowland areas. In India, 30% of the rice growing area (12-14 M ha) is prone to flash flooding with average productivity of only 0.5-0.8 t ha −1 .

In soil, plant roots coexist with bacteria and fungi that produce siderophores capable of sequestering the available iron. Microbial cyanogenesis has been demonstrated in many species of fungi and in a few species of bacteria (e.g., Chromobacterium and Pseudomonas). Fluorescent Pseudomonas isolates P29, P59, P144, P166, P174, P187, P191 and P192 were cyanogenic and produced siderophores in the presence of a strong chelater 8-Hydroxyquinoline (50 mg/l). A simple confrontation assay for identifying potential antagonists was developed. Fluorescent Pseudomonas isolates P66, P141, P144, P166 and P174 were antagonistic against both Rhizoctonia solani and Sclerotium rolfsii. Vigorous plant growth was observed following seed bacterization with P141, P200 and P240. In field experiments, seed bacterization with selected bacterial isolates resulted in reduced collar rot (S. rolfsii) incidence.

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