Seed discoloration other than called grain discoloration in rice is an emerging serious threat to global rice production. It is characterized by a change on the seed coat color due to fungal infestation which causes a decline in seed quality, germination potential, crop establishment, milling quality and market value. It is a complex disease mainly caused by different genera of fungi such as Fusarium spp., Bipolaris spp., Alternaria spp., Curvularia lunata, Sarocladium oryzae, and Aspergillus etc. Several other saprophytic fungi and pathogenic bacteria like Burkholderia glumae are also associated with the disease. The severity of infection is highly influenced by the environmental factors like high moisture and temperature fluctuations coupled with rainfall. It also results in reduced nutritional qualities like starch and protein content, increased phenolic compounds, reduced vigour, overall crop establishment and storability. Understanding the pathogen biology, epidemiology and host-pathogen interaction will help in formulating integrated disease management (IDM) measures like cultural, chemical, biological, and genetic methods to effectively reduce the losses. There is still limited understanding of host-pathogen interactions, pathogen/s associated with the disease, scanty information on host plant resistance mechanisms. The current review compiles available information on the origin, economic impact, symptoms, causal organisms, associated mycotoxins and their effect on plant physiology and finally, integrated management strategies.

Brown planthopper [Nilaparvata lugens] is a serious pest of rice (Oryza sativa) in all the rice-growing regions of the World. In the present study, 28 red rice genotypes were selected from the initial screening of 215 genotypes and evaluated for resistance to N. lugens under glass-house conditions for two seasons. The promising genotypes were also studied for antixenosis and tolerance mechanisms of resistance. Among red rice genotypes, Mata Meher, Manipuri black, Hermonona, and Sonahanan reported high resistance to N. lugens through antixenosis and tolerance mechanisms. These resistant genotypes could serve as a valuable source for developing brown plant hopper resistant varieties.

Rice crop is often attacked by several insect pests during its growth stages. Brown planthopper, BPH, is the most serious pest of rice which can cause epidemic losses. Though deployment of durable resistant variety is the safest and economic method of management, the breakdown of resistance is commonly being observed in several cases forcing farmers to use chemical pesticides. Under the negative effects of these chemical pesticides, Silicon provides a promising option as it is beneficial to plants, in alleviating the biotic and abiotic stress by imparting resistance. In the present investigation, attempt was made to manage the pest using different sources of Silicon mainly, Ca2SiO4, KSiO3 and MgSiO3. All the three forms of Si were applied as seed priming and soil application at 50 and 100 mg/kg of soil. The results showed that, application of Silicon sources enhanced plant growth promoting traits like germination (7–11.50

Fall armyworm (FAW), Spodoptera frugiperda (J.E. Smith) has significantly affected maize crop yields, production efficiency, and farmers’ incomes in the Indian Eastern Gangetic Plains region since it was first observed in India in 2018. A lack of awareness by maize growers of the appropriate selection, method, and timing of insecticide application not only creates a barrier to sustainable FAW control but also contributes to increased environmental pollution, reduced human health and increased production costs. We demonstrated that FAW inflicted the most damage in early whorl growth stage of maize, regardless of whether chemical insecticides were applied. FAW egg masses and larvae collected from maize fields in which no insecticides had been sprayed showed high parasitism rates by parasitoid wasps; in contrast fields that had been sprayed had much lower rates of parasitism on FAW. Ten hymenopteran parasitoids were observed in maize fields across the study region, suggesting a diversity of natural methods to suppress FAW in maize at different growth stages. These included two FAW egg parasitoids and eight FAW larval parasitoids. Microplitis manilae Ashmead was the most abundant FAW larval parasitoid species, and Telenomus cf. remus was the dominant FAW egg parasitoid species. Endemic FAW parasitoids such as those observed in this study have great potential as part of a sustainable, cost-effective agroecological management strategy, which can be integrated with other methods to achieve effective control of FAW.

The brown planthopper [Nilaparvata lugens (Stål.)] is one of the most destructive insect pests in all the rice-growing regions of the world. The pest is complicated to manage through the blanket application of chemical pesticides. The development of stable, durable N. lugens-resistant rice varieties is the most economical and efficient strategy to manage the pest. Landraces of red rice genotypes possess numerous nutritional and stress-resistant properties, though an exclusive study on the same is yet to be carried out. In the present study, we evaluated 28 red rice genotypes, along with two resistance checks and one susceptibility check, for their resistance to N. lugens. These promising lines revealed differential responses in the defense mechanism against the pest. The resistant accessions showed a greater accumulation of phenols, peroxidase, polyphenol oxidase, catalase, and superoxide dismutase under N. lugens-stressed conditions. However, the concentration of soluble proteins was substantially decreased in all the test genotypes. The concentration of crude silica was at maximum in highly resistant genotypes. Six red rice genotypes, namely Mata Meher, Manipuri Black, Hermonona, Sonahanan, Bavdi, and Bacharya Khuta fall under the highly resistant category, and can be utilized as valuable sources of resistance in breeding programs.

Bakanae, caused by a fungal pathogen Fusarium fujikuroi is a major burden in rice cultivation. Management of this disease is crucial as it has the risk of being associated with the seed while exporting. Regular application of fungicides promotes the development of resistance to the molecule, and the lack of newer compounds paved the way for alternative management strategies. Salicylic acid (SA) and potassium silicate (PS) have gained momentum recently for their beneficial effects in promoting plant growth and controlling disease. Potassium silicate and salicylic acid are known to play a key role in enhancing plant defense. The present study investigates the individual and combined effect of PS and SA seed priming for plant growth and defense responses against Fusarium fujikuroi . The seed priming combined with SA (100 mg/L) and PS (1.0%) effectively controlled the bakanae disease incidence. In addition, it was also effective on growth parameters like improved germination, root and shoot length, plant biomass, and seedling vigor. Accumulation of defense enzymes like phenylalanine ammonialyase (PAL), polyphenol oxidase (PPO), Peroxidase (POD), and phenol derivatives was significantly higher in the treated plants. The maximum activity of these defense enzymes was recorded in PS+SA-treated plants at 21 DAS. The plant treated with SA-100 mg/L+ PS-1% showed the best response without any phytotoxic effect. The information gathered in the present study suggests that seed priming of SA-100 mg/L+ PS-1% can promote plant growth and suppress bakanae disease in rice. This research demonstrates how PS and SA can be used to combat the F. fujikuroi in rice by activating key defense enzymes. Additionally, applying these substances to plants stimulates their antioxidant defences, which indirectly prevents the spread of disease. In place of fungicides, the PS and SA treatment options are harmless for the environment and can be used to manage the bakanae disease. Future studies may be initiated to identify potential mechanisms behind the combined effects of SA and PS on plant growth promotion and disease suppression.

Rice (Oryza sativa L) being one of the imperative food crops of the word contributes immensely to the food and nutritional security of India. The cultivation of rice is changed over the decades from a simple cultivation practices to the advanced cultivation to increase yield. Increased in rice yields especially after 1960s is mainly due to the introduction of high yielding semi-dwarf varieties which requires more inputs like chemical fertilizers, water and other resources. As a result, India achieved self sufficiency in rice and currently producing more than 115 MT of rice to meet country’s demand. Now India is exporting rice to other nations and earning foreign returns. With the change in rice cultivation practices, problems also aroused side by side. A number of biotic and abiotic stresses emerged as major constraints for rice cultivation in diverse agro-climatic conditions and growing ecologies. Diseases are the major biotic constraints to rice which can reduce the yields by 20–100% based on severity. Major diseases like blast, brown spot, bacterial blight, sheath blight and tungro still causing more damage and new minor diseases like bakanae, false smut, grain discoloration, early seedling blight, narrow brown spot, sheath rot have emerged as major problems. The losses due to these diseases may 1–100% based on the growing conditions, varietal susceptibility etc.., At present no significant source of resistance available for any of the above emerging diseases. But looking into the severity of these diseases, it is very important to address them by following integrated management practices like cultural, mechanical, biological and finally chemical control. But more emphasis has to be given to screen gerrmplasm against these diseases and identify stable source of resistance. Finally utilizing these sources in resistance breeding program by employing molecular breeding tools like marker assisted selection (MAS), marker assisted back cross breeding (MABB), gene pyramiding and transgenic tools. The present chapter discusses the importance of these emerging minor diseases of rice, the losses and possible management measures including resistance breeding.

Studies were undertaken to evaluate the rice genotypes of Sikkim and Tripura for their resistance against brown planthopper (BPH) under glasshouse conditions.Among 74 rice genotypes phenotyped, a genotype (AC-39843) was considered as resistant and two other genotype (AC-39842 and AC-39877) of Tripura were categorized as moderately resistant to BPH.To understand their mechanism of resistance, resistant genotypes were evaluated for different parameter of antixenosis and antibiosis.The antixenosis and antibiosis studies in terms of nymphal setting preference, per cent unhatchability of eggs, nymphal survival and development, honeydew excretion, probing mark test, plant dry weight loss and defence enzymes (Peroxidase, polyphenol oxidaseand catalase) indicated that these genotypes showed confirmation of resistance to BPH compared to susceptible check TN 1.Among resistant genotypes, AC-39843 recorded lowest sugar content followed by AC-39842 and AC-39877 compared to TN1.Total phenol content in AC-39843 was highest followed by AC-39877 and AC-39842.Resistant genotypes found in the study could be used as new resistant donors and utilized in resistance breeding programme against brown planthopper in rice.

India is the second most populated country only after China. The majority of the Indian population depends on agriculture for their livelihood. Post green era has resulted in tremendous increase in production and productivity of major crops which resulted in food and nutritional security of the nation. Though nation has achieved self sufficiency in food production, the production and productivity of pulses is not in an encouraging growth rate. So India till today importing major pulses from other countries. Pulses constitute an excellent supplement of proteins in vegetarian diet of human beings and play a significant role in correcting the wide spread malnutrition in the country. Cultivation of International Journal of Current Microbiology and Applied Sciences ISSN: 2319-7706 Volume 8 Number 07 (2019) Journal homepage: http://www.ijcmas.com

Red rice is the reservoir of large amount of phytochemicals such as carotenoids, phenolics, alkaloids, nitrogen and organosulfur containing compounds, possesses antioxidant properties, richer source of protein, zinc and have nutritive and medicinal value. Present study examines the utility of red rice accessions for their resistance against Brown planthopper (BPH), a damaging insect pest of rice. A total of 215 red rice accessions along with susceptible check TN1, resistance checks PTB-33 and Salkathi were evaluated under greenhouse condition of the National Rice Research Institute (NRRI), Cuttack. Accessions were screened using standard seed box technique for mass screening followed by replicated screening for the confirmation of resistant reaction. Only four accessions, namely, matameher, manipuri black sonahanan and hormonona were found to be highly resistant (score-1) while eleven showed resistant reaction (Score-3) and 13 were moderately resitant (Score-5) to BPH. Mechanism of resistance was studied in the resistant accessions through the method of antixenosis or nymphal preference to plants. Matameher and manipuri black showed least nymphal preference as compared to the susceptible check TN1. Resistant genotypes identified and confirmed in the present study can be grown as resistant varieties in BPH endemic areas and also can be utilised in resistance breeding programme to develop BPH-resistant varieties with other desired traits.