Impact of Nitrogen, Phosphorus and Potassium on Brown Planthopper and Tolerance of Its Host Rice Plants

The brown planthopper(BPH),Nilaparvata lugens(St?l),appeared as a devastating pest of rice in Asia. Experiments were conducted to study the effects of three nutrients,nitrogen(N),phosphorus(P) and potassium(K),on BPH and its host rice plants. Biochemical constituents of BPH and rice plants with varying nutrient levels at different growth stages,and changes in relative water content(RWC) of rice plants were determined in the laboratory. Feeding of BPH and the tolerance of rice plants to BPH with different nutrient levels were determined in the nethouse. Concentrations of N and P were found much higher in the BPH body than in its host rice plants,and this elemental mismatch is an inherent constraint on meeting nutritional requirements of BPH. Nitrogen was found as a more limiting element for BPH than other nutrients in rice plants. Application of N fertilizers to the rice plants increased the N concentrations both in rice plants and BPH while application of P and K fertilizers increased their concentrations in plant tissues only but not in BPH. Nitrogen application also increased the level of soluble proteins and decreased silicon content in rice plants,which resulted in increased feeding of BPH with sharp reduction of RWC in rice plants ultimately caused susceptible to the pest. P fertilization increased the concentration of P in rice plant tissues but not changed N,K,Si,free sugar and soluble protein contents,which indicated little importance of P to the feeding of BPH and tolerance of plant against BPH. K fertilization increased K content but reduced N,Si,free sugar and soluble protein contents in the plant tissues which resulted in the minimum reduction of RWC in rice plants after BPH feeding,thereby contributed to higher tolerance of rice plants to brown planthopper.

Using Environmentally Friendly Hydrogels to Alleviate the Negative Impact of Drought on Plant

The use of natural hydrogels in agriculture provides solutions to many problems without threatening the environment. This study aims to evaluate the potential impact of environmentally friendly hydrogels (pectin, starch and pectin + starch) in reducing the negative effects of drought stress on tomato yield and quality. Two different peels (orange peel and banana peel) are used to prepare environmentally friendly hydrogels. The water retention efficiency of hydrogels has been studied. Greenhouse experiment for tomato under drought stress was conducted during 2019. These hydrogels were used under several level of irrigation (100%, 75%, and 50% FC), soil without hydrogel was used as a control. The results showed that the eco-friendly hydrogels (starch, pectin, and pectin + starch) had capacity retention of water for a long time. The obtained data from the greenhouse experiment showed that the eco-friendly hydrogel showed a positive effect on retention of water and increase the soil moisture content compared to control. The highest increase was observed at pectin + starch treatment. This increase reached to 2.8-, 2.4- and 2.0-fold for 100%, 75% and 50% FC compared to the control. Eco- friendly hydrogel application under different drought conditions led to improve yield and quality of tomato fruits. Moreover, conversion of agricultural wastes to hydrogels and the use of these eco-friendly materials instead of synthetic hydrogels are necessary to utilize the limited natural resources and decrease the harmful impact of agricultural wastes on the environment and pave the way for the transition to a sustainable agriculture system.

The Impact of Inoculum Preparation Media on Pollutant Removal through Phycoremediation of Agricultural Drainage Water by Desmodesmus sp.

Water is the most essential natural resource for the future development.Agriculture production is extensively water-dependent and a significant polluter of water resources.So,this work investigated the effect of two different preparation media[Bold’s Basal Medium(BBM)and Domiati cheese whey(DCW)]for agricultural drainage water(ADW)remediation.All treatments were incubated for 6 days.According to the results of biomass productivity,specific growth rate,photosynthetic pigments,and biochemical composition,Desmodesmus sp.can grow in drainage water without dilution.The two treatments significantly reduced the concentration of nitrate,phosphate,chemical oxygen demand,and sodium in ADW.Finally,using cheese whey with BBM as inoculum preparation media enhanced the lipid accumulation in the algal biomass(25.4%w/w)and gave the best biodiesel properties among treatments.Therefore,combining remediation of drainage water with microalgae mass production can achieve the sustainability of agriculture.

Carbon stock estimation for tree species of Sem Mukhem sacred forest in Garhwal Himalaya, India

Carbon stock estimation was conducted in tree species of Sem Mukhem sacred forest in district Tehri of Garhwal Himalaya, Uttara- khand, India. This forest is dedicated to Nagraj Devta and is dominated by tree species, including Quercus floribunda, Quercus semecarpifolia and Rhododendron arboreum. The highest values of below ground bio- mass density, total biomass density and total carbon density were （34.81±1.68） Mg·ha^-1, （168.26±9.04） Mg·ha^-1 and （84.13±4.18） Mg·ha^-1 for Pinus wallichiana. Overall values of total biomass density and total carbon density calculated were 1549.704 Mg·ha^-1 and 774.77 Mg·ha^-1 respectively. Total value of growing stock volume density for all species was 732.56 m3·ha^-1 and ranged from （144.97±11.98） m3·ha^-1 for Pinus wallichiana to （7.78±1.78） m3·ha^-1for Benthamidia capitata.

Genetic mapping of quantitative trait loci for the stigma exsertion rate in rice(Oryza sativa L.)

The efficiency of hybrid rice seed production can be improved by increasing the percentage of exserted stigmas. To identify quantitative trait loci （QTLs） for this trait, we conducted QTL mapping using 75 chromosome segment substitution lines （CSSLs） developed from a cross between the donor parent, Xieqingzao B （XQZB）, a maintainer line which has high stigma exsertion and the recurrent parent, Zhonghui 9308 （ZH9308）, a restorer line which has low stigma exsertion. Atotal of nine QTLs （qSSE5, qSSE10, qSSE11, qDSE10, qDSE11, qTSE5, qTSE6, qTSE10, and qTSE11） for single stigma exsertion （ssE）, dual stigma exsertion （DSE） and total stigma exsertion （TSE） were assessed in two environments （Hainan and Zhejiang）. Six of these QTLs （qSSE10, qSSE11, qDSE10, qDSE11, qTSE10, and qTSE11） were found in both environ- ments, while one QTL （qTSE6） was found in only Hainan, and two QTLs （qSSE5 and qTSE5） were found in only Zhejiang. The qSSE10, qSSE11, qDSE10, qDSE11, qTSE6, qTSE10, and qTSE11 alleles, which are derived from the parent XQZB, exhibited a positive additive effect. In contrast, the qSSE5 and qTSE5 alleles, which are derived from the parent ZH9308, exhibited a negative additive effect. The SSE, DSE and TSE traits were significantly correlated with each other in an en- vironmentally dependent manner. These results indicated that the lines showing higher values for SSE were more likely to exhibit increased values for DSE, which would ultimately increase TSE. To evaluate the advantage of exserted stigmas for cross-pollination, single, dual and total stigma exsertion should be considered separately in future attempts at genetic improvement to achieve increased production of rice hybrid seeds. This study also provides information for fine mapping, gene cloning and particularly marker-assisted selection （MAS）, on the latter and with an emphasis the phenotypic effects and implications of the QTLs for practical use in hybrid rice breeding.

Improvement of Upland Rice Variety by Pyramiding Drought Tolerance QTL with Two Major Blast Resistance Genes for Sustainable Rice Production

Varalu is an early maturing rice variety widely grown in the rainfed ecosystem preferred for its grain type and cooking quality.However,the yield of Varalu is substantially low since it is being affected by reproductive drought stress along with the blast disease.The genetic improvement of Varalu was done by introgressing a major yield QTL,qDTY_(12.1),along with two major blast resistance genes i.e.Pi54 and Pi1 through marker-assisted backcross breeding.Both traits were transferred till BC_(2) generation and intercrossing was followed to pyramid the two traits.Stringent foreground selection was carried out using linked markers as well as peak markers(RM28099,RM28130,RM511 and RM28163)for the targeted QTL(qDTY_(12.1)),RM206 for Pi54 and RM224 for Pi1.Extensive background selection was done using genome-wide SSR markers.Six best lines(MSM-36,MSM-49,MSM-53,MSM-57,MSM-60 and MSM-63)having qDTY_(12.1) and two blast resistance genes in homozygous condition with recurrent parent genome of 95.0%-96.5% having minimal linkage drag of about 0.1 to 0.7 Mb were identified.These lines showed yield advantage under drought stress as well as irrigated conditions.MSM-36 showed better performance in the national coordinated trials conducted across India,which indicated that improved lines of Varalu expected to replace Varalu and may have an important role in sustaining rice production.The present study demonstrated the successful marker-assisted pyramiding strategy for introgression of genes/QTLs conferring biotic stress resistance and yield under abiotic stress in rice.

Physiological Studies on Ratoonability of Sugarcane Varieties under Tropical Indian Condition

The ratoon crop occupies approximately 40% of the total area of sugarcane crop in tropical India. The main reason for the lower average cane productivity is the yield decline in ratoon crops (40 - 50 t/ha) despite the release of the high yielding varieties and advanced cane production technology. The physiological factors associated with ratooning performance and the variation in growth and yield were studied in 11 sugarcane varieties in two cycles of one plant and two ratoon crops each. The first ratoon and second ratoon crop showed 17.0% and 28.1% reduction in tiller production and 15.5% and 15.7% reduction in NMC, respectively, over plant crop. The differences in growth parameters between the plant and ratoon crops at the formative phase were lesser than that of grand growth and maturity phases. Varieties Co 86032, Co 97008, Co 95020 Co 99004 and Co 2000-10 showed better physiological efficiency in terms of plant height, shoot population, leaf size, TDMP, partitioning efficiency, chlorophyll content and nitrate reductase activity and significantly higher yield components such as NMC, SCW, cane length, internodal length as well as cane yield compared to other varieties. The higher reduction in ratoon yield in Co 99008, Co 94012, Co 8021 and Co 97009 (>35.00% reduction) was due to higher reduction in tiller production associated with stunted plant growth and root system, reducetion in individual leaf size and LAI, TDMP, total chlorophyll content, NMC, internodal length and SCW. The results obtained indicated that the plant height, TDMP, stem partitioning, leaf size, total chlorophyll content, SCW, cane length and cane girth were highly associated with yield of first and second ratoon crops than that of plant crop. Therefore the difference in the association between physiological parameters with yield of plant and ratoon crops therefore decides the ratooning potential of the crop.

Ecological fitness of brown planthopper, Nilaparvata lugens (Stål), to rice nutrient management

Introduction:The brown planthopper(BPH),Nilaparvata lugens(Stål)(Hemiptera:Delphacidae),is a notorious insect pest of rice.Nutrient supplementation can alter plant biochemical compositions which may indirectly affect on ecological fitness parameters of its insect pest.However,few findings are available on nutrient-induced ecological fitness of BPH and relationship of BPH fitness parameters with its host rice plant biochemical contents.Methods:We studied the main and interaction effects of nitrogen(N),phosphorus(P),and potassium(K)inputs on BPH fitness,as measured by the following variables:nymph survival,nymphal duration,adult body weight,and its survival.Brown planthopper fitness parameters were regressed as function of rice plant(Oryza sativa)biochemical composition.A completely randomized design with four replications in a factorial scheme was used considering N,P,and K levels as factors.Results:Nitrogen application to the host rice plants provided greater survival and enhanced body weight of BPH.The nymphal duration was found to decrease with N subsidy that caused shorter generation time of BPH.Nitrogenous compounds N and soluble protein(SP),total free sugar(TFS),and silicon(Si)content in rice plant tissue correlated strongly with all fitness traits of BPH.Nitrogen,SP,and TFS associated positively with BPH survival and body weight,while negatively with nymphal duration.In contrast,Si had negative correlation with BPH survival and body weight,but positive with nymphal duration.Phosphorus supplementation to host plant contributed to increase BPH body weight.Relationships of P with all parameters of BPH were weak except body weight which was highly significant and positive.Interaction between N and P inputs demonstrated significant effect on BPH body weight.Application of K had no significant effect on BPH survival and development.Regression analysis did not detect significant relationship of BPH fitness parameters with plant tissue content of K.Conclusions:The results suggest that BPH ecological fitness characters were improved after N and P fertilization to rice plants which are associated with biochemical content of rice plant.Therefore,N and P inputs should be used judiciously in rice cultivation to keep BPH ecological fitness potential at minimum level.

Soil Microbiological Activity and Carbon Dynamics in the Current Climate Change Scenarios:A Review

Microbial activities are affected by a myriad of factors with end points involved in nutrient cycling and carbon sequestration issues.Because of their prominent role in the global carbon balance and their possible role in carbon sequestration, soil microbes are very important organisms in relation to global climate changes. This review focuses mainly on the responses of soil microbes to climate changes and subsequent effects on soil carbon dynamics. An overview table regarding extracellular enzyme activities(EAA) with all relevant literature data summarizes the effects of different ecosystems under various experimental treatments on EAA. Increasing temperature, altered soil moisture regimes, and elevated carbon dioxide significantly affect directly or indirectly soil microbial activities.High temperature regimes can increase the microbial activities which can provide positive feedback to climate change, whereas lower moisture condition in pedosystem can negate the increase, although the interactive effects still remain unanswered. Shifts in soil microbial community in response to climate change have been determined by gene probing, phospholipid fatty acid analysis(PLFA),terminal restriction length polymorphism(TRFLP), and denaturing gradient gel electrophoresis(DGGE), but in a recent investigations,omic technological interventions have enabled determination of the shift in soil microbe community at a taxa level, which can provide very important inputs for modeling C sequestration process. The intricacy and diversity of the soil microbial population and how it responds to climate change are big challenges, but new molecular and stable isotope probing tools are being developed for linking fluctuations in microbial diversity to ecosystem function.

Comparison of blood glucose responses by cane sugar(Saccharum offi cinarum)versus coconut jaggery(Cocos nucifera)in type 2 diabetes patients

Type 2 diabetic mellitus is a predominant metabolic disorder that has a direct impact on human health.Although scientific data are deficit,coconut jaggery has been suggested as a better alternative for cane sugar by some individuals.This study was conducted to assess the credibility of this claim.Coconut jaggery was prepared at Coconut Research Institute,Sri Lanka and nutritional composition of coconut jaggery was compared with cane sugar using standard methods.Significantly higher(P<0.05)moisture(8.92±0.22)%,ash(2.09±0.33)%,protein(1.91±0.28)%,fat(0.14±0.02)%and fiber(0.05±0.03)%contents were observed in coconut jaggery compared to cane sugar.The total starch and total sugar content of the coconut jaggery was significantly(P<0.05)lower than that of the cane sugar.Forty-three patients(Male:16,Female:27)with type 2 diabetes from the Endocrinology unit,National Hospital Colombo,Sri Lanka were voluntarily engaged in the study,subjected to an initial health screening.Then,determination of postprandial blood glucose responses after intake of the standard(glucose),cane sugar and coconut jaggery.Average age of the selected group was(48.19±7.95)years and they were all overweight(BMI>23.0).The mean fasting blood glucose level and HbA1c of the subjects were(149.05±54.88)mg/dL and(9.170±2.022)%,respectively.There was no significant difference(P>0.05)in peak blood glucose concentrations or incremental area under the curve in blood glucose response of two test food.Therefore,coconut jaggery cannot be considered as a healthy substitute for cane sugar in type 2 diabetic patients.