Highlights Agriculture plays an important role in a country's economy. In modern intensive agricultural practices, chemical fertilizers and pesticides are applied on large scale to increase crop production in order to meet the nutritional requirements of the ever-increasing world population. However, rapid urbanization with shrinking agricultural lands, dramatic change in climatic conditions and extensive use of agrochemicals in agricultural practices has been found to cause environmental disturbances and public health hazards affecting food security and sustainability in agriculture. Besides this, agriculture soils are continuously losing their quality and physical properties as well as their chemical (imbalance of nutrients) and biological health due to indiscriminate use of agrochemicals. Plant-associated microbes with their plant growth- promoting traits have enormous potential to solve these challenges and play a crucial role in enhancing plant biomass and crop yield under greenhouse and field conditions. The beneficial mechanisms of plant growth improvement include enhanced availability of nutrients (i.e., N, P, K, Zn and S), phytohormone modulation, biocontrol of phytopathogens and amelioration of biotic and abiotic stresses. This plant-microbe interplay is indispensable for sustainable agriculture and these microbes may perform essential role as an ecological engineer to reduce the use of chemical fertilizers. Various steps involved for production of solid-based or liquid biofertilizer formulation include inoculum preparation, addition of cell protectants such as glycerol, lactose, starch, a good carrier material, proper packaging and best delivery methods. In addition, recent developments of formulation include entrapment/microencapsulation, nano-immobilization of microbial bioinoculants and biofilm-based biofertilizers. Thus, inoculation with beneficial microbes has emerged as an innovative eco-friendly technology to feed global population with available resources. This review critically examines the current state-of-art on use of microbial strains as biofertilizers in different crop systems for sustainable agriculture and in maintaining soil fertility and enhancing crop productivity. It is believed that acquisition of advanced knowledge of plant-PGPR interactions, bioengineering of microbial communities to improve the performance of biofertilizers under field conditions, will help in devising strategies for sustainable, environment-friendly and climate smart agricultural technologies to deliver short and long terms solutions for improving crop productivity to feed the world in a more sustainable manner.

A field experiment was conducted during the pre-kharif season of 2012 and 2013 at Varanasi to study the effect of nitrogen, phosphorus and potassium (NPK) (100% and 125% recommended dose of fertilizer), sulfur (0, 25 and 50 kg S ha −1 ) and zinc (0, 5 and 10 kg Zn ha −1 ) fertilization on growth, yield, economics and quality of baby corn. Growth attributes like plant height, number of green leaves, stem girth, dry matter plant −1 , crop growth rate (CGR), chlorophyll content of leaves, yield attributes like number of baby cobs plant −1 , cob and corn weight, length and girth of corn as well as yield of cob, corn and green fodder besides gross return, net return and benefit:cost ratio were increased significantly with application of 125% RDF (recommended dose of fertilizer) over 100% RDF. Increasing level of sulfur application up to 50 kg S ha −1 had a marked effect on all the growth characters, yield attributes and yield. Each increment of zinc application up to 10 kg Zn ha −1 correspondingly improved growth, yield attributes, cob yield, corn yield and green fodder yield as well as gross return, net return and the benefit:cost ratio.

Biofertilizers contribute in N(2) fixation, P solubilization, phytohormone production and thus enhance plant growth. Beneficial plant-microbe interactions and the stability and effectiveness of biofertilizer depend upon the establishment of bacterial strains in the rhizosphere of the plant. This interaction depends upon many factors, one of them being plant exudates. Root exudates are composed of small organic molecules like carbonic acids, amino acids or sugars etc., which are released into the soil and bacteria can be attracted towards these exudates due to chemotaxis. The chemotactic behaviour of Azotobacter strains was studied using cotton (Desi HD 123 and American H 1098) and wheat (WH 711) seedlings and the root exudates of these two plants were chemically characterized. Analysis of the root exudates revealed the presence of sugars and simple polysaccharides (glucose), amino acids (glutamate, lysine) and organic acids (citric acid, succinic acid, maleic acid, malonic acid). Differences between cotton cultivars in root exudates were observed which influenced chemotactic response in Azotobacter. These results indicate colonization with rhizobacteria which implies that optimal symbionts, on the sides of both plant cultivar and bioinoculant bacteria can lead to better plant growth under cultivation conditions.

Fifty four genotypes including four checks were grown in a RBD with three replications during Rabi 2010-11 at Vegetable Experimental Research Farm, Nauni, Solan HP to estimate the parameters of variability and association of important characters with yield in garden pea. Analysis of variance showed significant differences among the genotypes for all the morphological characters under study. The genotypic and phenotypic coefficients of variation were high for total soluble solids, total sugars, pod yield per hectare and total phenols. High heritability estimates coupled with high to moderate genetic gain observed for pod yield (kg/plot), node at which the first flower appear (number), number of pods per plant and total Phenols (g/100g). Pod yield was positively correlated with number of pods per plant, pod length (cm), number of seeds per pod and shelling percentage thereby indicating that the selection based on these traits could be effective for improvement of green shelled peas yield.

Astaxanthin is a ketocarotenoid, super antioxidant molecule. It has higher antioxidant activity than a range of carotenoids, thus has applications in cosmetics, aquaculture, nutraceuticals, therapeutics, and pharmaceuticals.Naturally, it is derived from Haematococcus pluvialis via a one-stage process or two-stage process. Natural astaxanthin significantly reduces oxidative and free-radical stress as compared to synthetic astaxanthin. The present review summarizes all the aspects of astaxanthin, including its structure, chemistry, bioavailability, and current production technology. Also, this paper gives a detailed mechanism for the potential role of astaxanthin as nutraceuticals for cardiovascular disease prevention, skin protection, antidiabetic and anticancer, cosmetic ingredient, natural food colorant, and feed supplement in poultry and aquaculture. Astaxanthin is one of the high-valued microalgae products of the future. However, due to some risks involved or not having adequate research in terms of long-term consumption, it is still yet to be explored by food industries. Although the cost of naturally derived astaxanthin is high, it accounts for only a 1% share in total astaxanthin available in the global market. Therefore, scientists are looking for ways to cut down the cost of natural astaxanthin to be made available to consumers.

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A field experiment was conducted during kharif season 2008-09 and 2009 - 10 to evaluate the response of pigeonpea [Cajanus cajan (L.) Millsp.] + blackgram (Vigna mungo L.) intercropping system to integrated nutrient levels. Intercropping failed to influence the dry matter production /plant, CEC of roots, root N content, yield and quality parameters of both crops. Both the intercropping system gives significantly higher uptake of N, P and K when compared to sole pigeonpea. The available soil N, P, K after harvest of crop (s) was maximum observed under sole pigeonpea followed by normal intercropping and lowest inpaired intercropping. Application of 100% RDF+50% RDN+5 kg Zn/ha significantly increased the dry matter production /plant,CEC of roots, root N content, grain yield, protein content, protein harvest (kg/ha) and nutrient uptake (NPKS and Zn) in pigeonpea and black gram cropping system. Integrated use 100% RDF with 50% RDN and 5 kg Zn/ha also significantly improved the available N, P and K soil after harvest during both the years.The maximum net return (Rs. 117010) was obtained with combination of normal intercropping system + 100% RDF+50% RDN+5 kg Zn/ha followed by normal intercropping system + 50% RDF+100% RDN+5 kg Zn/ha (Rs. 115102).

The phyllosphere refers to the habitat provided by the aboveground parts of plants and on a global scale supports a large and complex microbial community. Microbial interactions in the phyllosphere can affect the fitness in natural communities and the productivity of agricultural crops. The structure of phyllospheric communities reflects immigration, survival and growth of microbial colonists, which is influenced by numerous environmental factors in addition to leaf physico-chemical properties. Culture-independent microbiological technologies as well advances in plant genetics and biochemistry provide methodological preconditions for exploring the interactions between plants and their microbiome in the phyllosphere. We are trying to focus here on the current knowledge of the composition of the foliar microbiome, its impact on plant growth and techniques for study of this science.