Harnessing weedy rice as functional food and source of novel traits for crop improvement.

A relative of cultivated rice (Oryza sativa L.), weedy or red rice (Oryza spp.) is currently recognized as the dominant weed, leading to a drastic loss of yield of cultivated rice due to its highly competitive abilities like producing more tillers, panicles, and biomass with better nutrient uptake. Due to its high nutritional value, antioxidant properties (anthocyanin and proanthocyanin), and nutrient absorption ability, weedy rice is gaining immense research attentions to understand its genetic constitution to augment future breeding strategies and to develop nutrition-rich functional foods. Consequently, this review focuses on the unique gene source of weedy rice to enhance the cultivated rice for its crucial features like water use efficiency, abiotic and biotic stress tolerance, early flowering, and the red pericarp of the seed. It explores the debating issues on the origin and evolution of weedy rice, including its high diversity, signalling aspects, quantitative trait loci (QTL) mapping under stress conditions, the intricacy of the mechanism in the expression of the gene flow, and ecological challenges of nutrient removal by weedy rice. This review may create a foundation for future researchers to understand the gene flow between cultivated crops and weedy traits and support an improved approach for the applicability of several models in predicting multiomics variables.

Productivity, soil health, and carbon management index of soybean-wheat cropping system under double zero-tillage and natural-farming based organic nutrient management in north-Indian plains.

Conservation-agriculture and organic-farming are two sustainable-agriculture approaches to ensure food security and environmental-sustainability. Hence, a field study assessed the productivity, soil-health and carbon-dynamics of soybean-wheat cropping system (SWCS) under four tillage and residue-management practices (TRMPs) viz., Conventional-tillage without residues (CT-R), conventional-tillage with residue-retention in both crops at 3 t ha-1 each (CT + R), zero-tillage without residues (ZT-R), and zero-tillage with residue-retention in both crops at 3 t ha-1 each (ZT + R); and five organic-nutrient-management-practices (ONMPs) in both crops viz., 100 % RDF (N1), 100 % RDN through FYM (N2), 100 % RDN through VC (N3), 100 % RDN through FYM + Biofertilizers + Cow-urine + Panchgavya + Jeevamrut (N4), and 100 % RDN through VC + Biofertilizers + Cow-urine + Panchgavya + Jeevamrut (N5), in split-plot-design replicated-thrice. Among TRMPs, ZT + R enhanced system-productivity (SEY) by ∼17.2 % over CT-R, besides improved soil available-N, P, K by 6.4, 6.5 and 6.5 %, respectively. SMBC, SMBN and SMBP were higher under ZT + R by 16.2, 21.5 and 10.8 % over CT-R, respectively. ZT + R had higher soil enzyme activities of DHA, Acid-P, ALP, URA, and FDA over CT-R by 19.4, 20.7, 21.5, 20.7 and 15.2 %, respectively. ZT + R also had higher VLC, ACP, LI and CMI over CT-R. Among ONMPs, the natural-farming based ONMP, N5 considerably improved SMBC, SMBN, SMBP, FDA, DHA, Acid-P, URA, and ALP by 12.7-12.9 % over N1 (100 % RDF). ONMP-N5 improved the available-N, P, K content over N1 by 6.6, 5.8 and 6.7 %, respectively. ONMP-N5 had higher (p < 0.05) microbial-count, VLC, APC, LI and CMI; however, system-productivity was ∼4.1 % lower than N1 in this two-years' short-study which further need investigation in multi-location long-term experiments. Overall, the dual-crop basis ZT + R at 6 t ha-1 year-1 + NF-based ONMPs (N5) may harness higher and sustained productivity under SWCS besides advancing soil-health and soil carbon-pools in sandy-loam soils of north-Indian plains and similar soils across south-Asia.

Zinc-solubilizing Bacillus spp. in conjunction with chemical fertilizers enhance growth, yield, nutrient content, and zinc biofortification in wheat crop.

Micronutrient deficiency is a serious health issue in resource-poor human populations worldwide, which is responsible for the death of millions of women and underage children in most developing countries. Zinc (Zn) malnutrition in middle- and lower-class families is rampant when daily calorie intake of staple cereals contains extremely low concentrations of micronutrients, especially Zn and Fe. Looking at the importance of the problem, the present investigation aimed to enhance the growth, yield, nutrient status, and biofortification of wheat crop by inoculation of native zinc-solubilizing Bacillus spp. in conjunction with soil-applied fertilizers (NPK) and zinc phosphate in saline soil. In this study, 175 bacterial isolates were recovered from the rhizosphere of wheat grown in the eastern parts of the Indo-Gangetic Plain of India. These isolates were further screened for Zn solubilization potential using sparingly insoluble zinc carbonate (ZnCO3), zinc oxide (ZnO), and zinc phosphate {Zn3(PO4)2} as a source of Zn under in vitro conditions. Of 175 bacterial isolates, 42 were found to solubilize either one or two or all the three insoluble Zn compounds, and subsequently, these isolates were identified based on 16S rRNA gene sequences. Based on zone halo diameter, solubilization efficiency, and amount of solubilized zinc, six potential bacterial strains, i.e., Bacillus altitudinis AJW-3, B. subtilis ABW-30, B. megaterium CHW-22, B. licheniformis MJW-38, Brevibacillus borstelensis CHW-2, and B. xiamenensis BLW-7, were further shortlisted for pot- and field-level evaluation in wheat crop. The results of the present investigation clearly indicated that these inoculants not only increase plant growth but also enhance the yield and yield attributes. Furthermore, bacterial inoculation also enhanced available nutrients and microbial activity in the wheat rhizosphere under pot experiments. It was observed that the application of B. megaterium CHW-22 significantly increased the Zn content in wheat straw and grains along with other nutrients (N, P, K, Fe, Cu, and Mn) followed by B. licheniformis MJW-38 as compared to other inoculants. By and large, similar observations were recorded under field conditions. Interestingly, when comparing the nutrient use efficiency (NUE) of wheat, bacterial inoculants showed their potential in enhancing the NUE in a greater way, which was further confirmed by correlation and principal component analyses. This study apparently provides evidence of Zn biofortification in wheat upon bacterial inoculation in conjunction with chemical fertilizers and zinc phosphate in degraded soil under both nethouse and field conditions.

Reactive oxygen species turnover, phenolics metabolism, and some key gene expressions modulate postharvest physiological deterioration in cassava tubers.

Rapid postharvest physiological deterioration (PPD) in cassava (Manihot esculenta Crantz) tuber is a significant concern during storage. The freshly harvested tubers start spoiling within 24 to 72 h. Accumulation of H2O2 is one of the earliest biochemical events that occurred during PPD, which was detected using the 3,3 diaminobenzidine (DAB) in two contrast cassava genotypes, MNP Local A (29-57 µg g-1) and Sree Prakash (64-141 µg g-1). Accumulating the fluorescence hydroxycoumarin compounds emitted by the cassava tubers observed under an ultraviolet (UV) lamp showed significant variations at 0, 3, 6, 9, 12, and 15 days of storage. The total phenolics and carotenoids significantly and negatively correlated with PPD progression; however, the anthocyanin and flavonoids positively correlated with the PPD-anchored ROS accumulation. The primary compound, Phthalic acid, di(2-propylpentyl) ester, was identified in both the cassava tubers, Sree Prakash (57.21 and 35.21%), and MNP Local A (75.58 and 60.21%) at 0, and 72 h of PPD, respectively. The expression of PPD-associated genes APX-2, APX-3, PAL, and AP was higher at 6-12 days of PPD, which signified the synthesis of ROS turnover and phenylpropanoid biosynthesis. A significant, strong, and positive correlation was established between the secondary metabolites and PPD signaling gene expression, which was inversely correlated with hydroxycoumarin and H2O2 accumulation. MNP Local A tubers exhibited longer storage life of 15 days with a low PPD score, higher metabolites synthesis, and gene expression. The PPD-resistant lines may be used to augment cassava breeding strategies for large-scale commercial and industrial use.

Elucidating the impact of boron fertilization on soil physico-chemical and biological entities under cauliflower-cowpea-okra cropping system in an Eastern Himalayan acidic Inceptisol.

Information on the role of boron (B) on soil physico-chemical and biological entities is scarce, and the precise mechanism in soil is still obscure. Present field investigation aimed to assessing the implication of direct and residual effect of graded levels of applied-B on soil biological entities and its concomitant impact on crop productivity. The treatments comprised of five graded levels of B with four replications. To assess the direct effect of B-fertilization, cauliflower was grown as a test crop wherein, B-fertilization was done every year. For assessment of succeeding residual effects of B-fertilization, cowpea and okra were grown as test crops and, B-fertilization was phased out in both crops. The 100% recommended dose of NPK (RDF) along with FYM was uniformly applied to all crops under CCOCS. Results indicated that the direct effect of B had the edge over residual effect of B in affecting soil physico-chemical and biological entities under CCOCS. Amongst the graded levels of B, application of the highest B level (2 kg ha-1) was most prominent in augmenting microbiological pools in soil at different crop growth stages. The order of B treatments in respect of MBC, MBN, and soil respiration at different crop growth stages was 2.0 kg B ha-1 > 1.5 kg B ha-1 > 1.0 kg B ha-1 > 0.5 kg B ha-1 > 0 kg B ha-1, respectively. Moreover, maximum recoveries of potentially mineralizable-C (PMC) and potentially mineralizable-N (PMN) were noticed under 2 kg B ha-1. Analogous trend was recorded in soil microbial populations at different crop growth stages. Similarly, escalating B levels up to 2 kg B ha-1 exhibited significantly greater soil enzymatic activities viz., arylsulphatase (AS), dehydrogenase (DH), fluorescein diacetate (FDA) and phosphomonoesterase (PMA), except urease enzyme (UE) which showed an antagonistic effect of applied-B in soil. Greater geometric mean enzyme activity (GMEA) and soil functional diversity index were recorded under 2 kg B ha-1 in CCOCS, at all crop growth stages over control. The inclusive results indicated that different soil physico-chemical and biological properties CCOCS can be invariably improved by the application of graded levels of B up to 2 kg B ha-1 in an acid Inceptisol.

Role of biostimulants in mitigating the effects of climate change on crop performance.

Climate change is a critical yield-limiting factor that has threatened the entire global crop production system in the present scenario. The use of biostimulants in agriculture has shown tremendous potential in combating climate change-induced stresses such as drought, salinity, temperature stress, etc. Biostimulants are organic compounds, microbes, or amalgamation of both that could regulate plant growth behavior through molecular alteration and physiological, biochemical, and anatomical modulations. Their nature is diverse due to the varying composition of bioactive compounds, and they function through various modes of action. To generate a successful biostimulatory action on crops under different parameters, a multi-omics approach would be beneficial to identify or predict its outcome comprehensively. The 'omics' approach has greatly helped us to understand the mode of action of biostimulants on plants at cellular levels. Biostimulants acting as a messenger in signal transduction resembling phytohormones and other chemical compounds and their cross-talk in various abiotic stresses help us design future crop management under changing climate, thus, sustaining food security with finite natural resources. This review article elucidates the strategic potential and prospects of biostimulants in mitigating the adverse impacts of harsh environmental conditions on plants.

Microbes-mediated integrated nutrient management for improved rhizo-modulation, pigeonpea productivity, and soil bio-fertility in a semi-arid agro-ecology.

Excessive dependence on chemical fertilizers and ignorance to organic and microbial inputs under intensive cropping systems are the basic components of contemporary agriculture, which evolves several sustainability issues, such as degraded soil health and sub-optimal crop productivity. This scenario urges for integrated nutrient management approaches, such as microbes-mediated integrated plant nutrition for curtailing the high doses as chemical fertilizers. Rationally, experiment has been conducted in pigeonpea at ICAR-IARI, New Delhi, with the aim of identifying the appropriate nutrient management technique involving microbial and organic nutrient sources for improved rhizo-modulation, crop productivity, and soil bio-fertility. The randomized block-designed experiment consisted nine treatments viz. Control, Recommended dose of fertilizers (RDF), RDF+ Microbial inoculants (MI), Vermicompost (VC), Farm Yard Manure (FYM), Leaf Compost (LC), VC + MI, FYM + MI, and LC + MI. Rhizobium spp., Pseudomonas spp., Bacillus spp., and Frateuria aurantia were used as seed-inoculating microbes. The results indicated the significant response of integration following the trend VC + MI > FYM + MI > LC + MI > RDF + MI for various plant shoot-root growth attributes and soil microbial and enzymatic properties. FYM + MI significantly improved the water-stable aggregates (22%), mean weight diameter (1.13 mm), and geometric mean diameter (0.93 mm), soil organic carbon (SOC), SOC stock, and SOC sequestration. The chemical properties viz. available N, P, and K were significantly improved with VC + MI. The study summarizes that FYM + MI could result in better soil physico-chemical and biological properties and shoot-root development; however; VC + MI could improve available nutrients in the soil and may enhance the growth of pigeonpea more effectively. The outcomes of the study are postulated as a viable and alternative solution for excessive chemical fertilizer-based nutrient management and would also promote the microbial consortia and organic manures-based agro-industries. This would add to the goal of sustainable agricultural development by producing quality crop produce, maintaining agro-biodiversity and making the soils fertile and healthy that would be a "gift to the society."

Double zero-tillage and foliar-P nutrition coupled with bio-inoculants enhance physiological photosynthetic characteristics and resilience to nutritional and environmental stresses in maize-wheat rotation.

Conventionally tilled maize-wheat cropping system (MWCS) is an emerging cereal production system in semi-arid region of south-Asia. This system involves excessive tillage operations that result in numerous resource- and production-vulnerabilities besides impeding environmental-stresses. Likewise, phosphorus is a vital nutrient that limits crop growth and development. It's a matter of great concern when ∼80% of Indian soils are low to medium in available-P due to its sparing solubility, resulting in crop stress and low yields. Hence, crop productivity, photosynthetic parameters and resilience to nutritional and environmental stresses were assessed in a MWCS using four crop-establishment and tillage management (CETM) practices [FBCT-FBCT (Flat bed-conventional tillage both in maize and wheat); RBCT-RBZT (Raised bed-CT in maize and raised bed-zero tillage in wheat); FBZT-FBZT (FBZT both in maize and wheat); PRBZT-PRBZT (Permanent raised bed-ZT both in maize and wheat)], and five P-fertilization practices [P100 (100% soil applied-P); P50+2FSP (50% soil applied-P + 2 foliar-sprays of P through 2% DAP both in maize and wheat); P50+PSB+AM-fungi; P50+PSB+AMF+2FSP; and P0 (100% NK with no-P)] in split-plot design replicated-thrice. The results indicated that double zero-tilled PRBZT-PRBZT system significantly enhanced the grain yield (6.1; 5.4 t ha-1), net photosynthetic rate (Pn) (41.68; 23.33 µ mol CO2 m-2 s-1), stomatal conductance (SC) (0.44; 0.26 mol H2O m-2 s-1), relative water content (RWC) (83.3; 77.8%), and radiation-use efficiency (RUE) (2.9; 2.36 g MJ-1) by 12.8-15.8 and 8.5-44.4% in maize and wheat crops, respectively over conventional tilled FBCT-FBCT. P50+PSB+AMF+2FSP conjugating soil applied-P, microbial-inoculants and foliar-P, had significantly higher Pn, SC, RUE and RWC over P100 besides saving ∼34.7% fertilizer-P under MWCS. P50+PSB+AMF+2FSP practice also had higher NDVI, PAR, transpiration efficiency and PHI over P100. Whereas lower stomatal limitation index (Ls) was observed under PRBZT-PRBZT system as compared to the conventional FBCT-FBCT system indicating that P is the limiting factor but not stomata. Hence, optimum P supply through foliar P-fertilization along with other sources resulted in higher grain yield by 21.4% over control. Overall, double zero-tilled PRBZT-PRBZT with crop residue retention at 6 t/ha per year, as well as P50+PSB+AMF+2FSP in MWCS, may prove beneficial in enhancing the crop productivity and, thereby, bolstering food security in semi-arid south-Asia region.

Orphan legumes: harnessing their potential for food, nutritional and health security through genetic approaches.

Legumes, being angiosperm's third-largest family as well as the second major crop family, contributes beyond 33% of human dietary proteins. The advent of the global food crisis owing to major climatic concerns leads to nutritional deprivation, hunger and hidden hunger especially in developing and underdeveloped nations. Hence, in the wake of promoting sustainable agriculture and nutritional security, apart from the popular legumes, the inclusion of lesser-known and understudied local crop legumes called orphan legumes in the farming systems of various tropical and sub-tropical parts of the world is indeed a need of the hour. Despite possessing tremendous potentialities, wide adaptability under diverse environmental conditions, and rich in nutritional and nutraceutical values, these species are still in a neglected and devalued state. Therefore, a major re-focusing of legume genetics, genomics, and biology is much crucial in pursuance of understanding the yield constraints, and endorsing underutilized legume breeding programs. Varying degrees of importance to these crops do exist among researchers of developing countries in establishing the role of orphan legumes as future crops. Under such circumstances, this article assembles a comprehensive note on the necessity of promoting these crops for further investigations and sustainable legume production, the exploitation of various orphan legume species and their potencies. In addition, an attempt has been made to highlight various novel genetic, molecular, and omics approaches for the improvement of such legumes for enhancing yield, minimizing the level of several anti-nutritional factors, and imparting biotic and abiotic stress tolerance. A significant genetic enhancement through extensive research in 'omics' areas is the absolute necessity to transform them into befitting candidates for large-scale popularization around the globe.

Assessment of heavy metal status and identification of source in soils under intensive vegetable growing areas of Brahmaputra valley, North East India.

This study investigated the content of Cd, Pb, Cr, and Ni in the soils of intensive vegetable growing areas of the Brahmaputra valley, North East India, to assess their status and detect any buildup of metals due to long-term and continuous application of agrochemicals and organic manures. The content of heavy metals was determined in eighty composite surface soil samples (0-20 cm) collected from eight different locations of the valley having a history of more than forty years of vegetable production. This finding is novel as no comprehensive investigation has been done till date in respect of the content of heavy metals in the intensive vegetable growing areas of Brahmaputra valley. The locations are considered free from any pollution caused by industrial effluent or urbanization processes. The investigational data showed that the content of Cd, Pb, Cr, and Ni in the soils ranged from 0.43 to 3.24, 6.00 to 22.90, 3.00 to 15.24, and 3.30 to 14.30 mg kg-1, respectively. The overall mean values of the heavy metals showed a decreasing order of Pb (14.79 mg kg-1) > Cr (8.87 mg kg-1) > Ni (8.37 mg kg-1) > Cd (1.43 mg kg-1). The findings of the study indicated significant enrichment of the metals in the surface soils over the local background values of the elements measured in the C horizon. Though the concentrations of Pb, Cr, and Ni of the soils were well below the reference levels used in different countries, Cd showed distinctly higher value with maximum enrichment level. The soils were categorized as slightly to moderately polluted based on different pollution indices. Based on the ecological risk index, soils were in the low-risk category, but in respect of Cd, most of the soils fell under the moderately risky category. Multivariate analysis suggested the predominance of lithogenic influence on the content of Pb, Ni, and Cr while Cd content bears a distinct signature of the anthropogenic source. The buildup of Cd in the studied soils is a matter of critical concern and needs proper monitoring and management strategies to avoid any potential detrimental effect on soil, crop, and human health.