Maize is a valuable source of food and feed worldwide. Maize endosperm protein is, however nutritionally poor due to the reduced levels of two essential amino acids, lysine and tryptophan. In this study, recessive opaque2 (o2) allele that confers enhanced endosperm lysine and tryptophan, was introgressed using marker-assisted backcross breeding into three normal inbred lines (HKI323, HKI1105 and HKI1128). These are the parental lines of three popular medium-maturing single cross hybrids (HM4, HM8 and HM9) in India. Gene-based simple sequence repeat (SSR) markers (umc1066 and phi057) were successfully deployed for introgression of o2 allele. Background selection using genome-based SSRs helped in recovering > 96% of recurrent parent genome. The newly developed quality protein maize (QPM) inbreds showed modified kernels (25-50% opaqueness) coupled with high degree of phenotypic resemblance to the respective recipient lines, including grain yield. In addition, endosperm protein quality showed increased lysine and tryptophan in the inbreds to the range of 52-95% and 47-118%, respectively. The reconstituted QPM hybrids recorded significant enhancement of endosperm lysine (48-74%) and tryptophan (55-100%) in the endosperm. The QPM hybrids exhibited high phenotypic similarity with the original hybrids for morphological and yield contributing traits along with responses to some major diseases like turcicum leaf blight and maydis leaf blight. The grain yield of QPM hybrids was at par with their original versions under multilocation testing. These elite, high-yielding QPM hybrids with improved protein quality have been released and notified for commercial cultivation, and hold significant promise for improving nutritional security.

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The complex parasitic strategy of Meloidogyne incognita appears to involve simultaneous expression of its pharyngeal gland-specific effector genes in order to colonize the host plants. Research reports related to effector crosstalk in phytonematodes for successful parasitism of the host tissue is yet underexplored. In view of this, we have used in planta effector screening approach to understand the possible interaction of pioneer genes (msp-18 and msp-20, putatively involved in late and early stage of M. incognita parasitism, respectively) with other unrelated effectors such as cell-wall modifying enzymes (CWMEs) in M. incognita. Host-induced gene silencing (HIGS) strategy was used to generate the transgenic eggplants expressing msp-18 and msp-20, independently. Putative transformants were characterized via qRT-PCR and Southern hybridization assay. SiRNAs specific to msp-18 and msp-20 were also detected in the transformants via Northern hybridization assay. Transgenic expression of the RNAi constructs of msp-18 and msp-20 genes resulted in 43.64–69.68% and 41.74–67.30% reduction in M. incognita multiplication encompassing 6 and 10 events, respectively. Additionally, transcriptional oscillation of CWMEs documented in the penetrating and developing nematodes suggested the possible interaction among CWMEs and pioneer genes. The rapid assimilation of plant-derived carbon by invading nematodes was also demonstrated using 14C isotope probing approach. Our data suggests that HIGS of msp-18 and msp-20, improves nematode resistance in eggplant by affecting the steady-state transcription level of CWME genes in invading nematodes, and safeguard the plant against nematode invasion at very early stage because nematodes may become the recipient of bioactive RNA species during the process of penetration into the plant root.

The use of modified clay minerals for adsorbing arsenic (As) in contaminated soils is an underexplored area of research. The adsorption behavior of As onto inorganically modified smectite and kaolinite both in aqueous and soil media was studied. X-ray diffraction, infra-red spectroscopy, scanning and transmission electron microscopy studies confirmed successful modification of smectite through Fe-exchange and Ti-pillaring, and kaolinite through phosphate binding. The modified smectites were more efficient than phosphate-bound kaolinite in adsorbing 2 As both in water and soil systems. Kinetic study revealed that the clay products reached adsorption equilibrium within h, and the data well fitted to the power function and simple Elovich equation (R 2 > 0.90). The Freundlich isotherm model best described the As adsorption data (R 2 > 0.86) of the modified clay products in both the systems. The Ti-pillared smectite exhibited the highest As adsorption capacity (156.54 µgg-1) in the aqueous medium, while the Fe-exchanged smectite was the best material in the soil system (115.63 µgg-1). The partition coefficient (Kd) and adsorption efficiency (%) data also maintained the similar trend. Precipitation of As and binuclear complex formation also took place in the soil system which made the metalloid non-labile as the time passed. The inorganically modified clay products reported here hold a great potential to adsorb As in contaminated groundwater, drinking water as well as soil.

Deficiency of iron and zinc causes micronutrient malnutrition or hidden hunger, which severely affects ~25% of global population. Genetic biofortification of maize has emerged as cost effective and sustainable approach in addressing malnourishment of iron and zinc deficiency. Therefore, understanding the genetic variation and stability of kernel micronutrients and grain yield of the maize inbreds is a prerequisite in breeding micronutrient-rich high yielding hybrids to alleviate micronutrient malnutrition. We report here, the genetic variability and stability of the kernel micronutrients concentration and grain yield in a set of 50 maize inbred panel selected from the national and the international centres that were raised at six different maize growing regions of India. Phenotyping of kernels using inductively coupled plasma mass spectrometry (ICP-MS) revealed considerable variability for kernel minerals concentration (iron: 18.88 to 47.65 mg kg–1; zinc: 5.41 to 30.85 mg kg–1; manganese: 3.30 to17.73 mg kg–1; copper: 0.53 to 5.48 mg kg–1) and grain yield (826.6 to 5413 kg ha–1). Significant positive correlation was observed between kernel iron and zinc within (r = 0.37 to r = 0.52, p < 0.05) and across locations (r = 0.44, p < 0.01). Variance components of the additive main effects and multiplicative interactions (AMMI) model showed significant genotype and genotype × environment interaction for kernel minerals concentration and grain yield. Most of the variation was contributed by genotype main effect for kernel iron (39.6%), manganese (41.34%) and copper (41.12%), and environment main effects for both kernel zinc (40.5%) and grain yield (37.0%). Genotype main effect plus genotype-by-environment interaction (GGE) biplot identified several mega environments for kernel minerals and grain yield. Comparison of stability parameters revealed AMMI stability value (ASV) as the better representative of the AMMI stability parameters. Dynamic stability parameter GGE distance (GGED) showed strong and positive correlation with both mean kernel concentrations and grain yield. Inbreds (CM-501, SKV-775, HUZM-185) identified from the present investigation will be useful in developing micronutrient-rich as well as stable maize hybrids without compromising grain yield.

Soil total organic carbon (TOC) is not sensitive enough to measure the short and medium term changes due to land use change practices, and thus meaningful fractions of soil organic carbon (SOC) should be measured. The objective of this study was to evaluate four agroforestry systems (AFSs) in order to test the hypothesis that agroforestry systems promote an increase in the soil organic carbon stocks and fractions, thus improving soil quality. For this, four 26 years old agroforestry systems consisting of multipurpose tree species (MPTs) (Michelia oblonga Wall, Parkia roxburghii G. Don, Alnus nepalensis D. Don, and Pinus kesiya Royle ex-Gordon) maintained at ICAR Research Complex, Umiam, Meghalaya, India were tested and compared with control plot for SOC stocks, microbial biomass carbon (MBC), readily oxidizable carbon (ROC), non-labile carbon (C NL ), particulate organic carbon (POC), and carbon management index (CMI). The soil samples were collected at five depths: 0-15, 15-30, 30-45, 45-60, and 60-75 cm. The TOC, POC, ROC, C NL and MBC in soils of agroforestry land use, on average, increased significantly by 26.3, 60.1, 27.1, 46.4 and 34 %, respectively in relative to control plot. However, the AFS consisting A. nepalensis recorded the highest mean SOC stocks (60.2 Mg ha -1 ), TOC (3.60 g 100 g -1 ), POC (5.42 g kg -1 ), ROC (10.16 g kg -1 ) and MBC (548 mg kg -1 ) than other AFSs. Furthermore, the CMI was highest under A. nepalensis (129.6) followed by M. oblonga (119.4), whereas P. kesiya showed the lowest value (91.1). The SOC stocks and fractions were, on average, 35.3 and 70 %, respectively higher in upper soil layer (0-15 cm) compared to subsurface soil layers (15-75 cm) in all the AFSs. The strong and positive correlation (P \ 0.05) between labile soil carbon fractions with TOC (r = 0.680** for POC; r = 0.683** for ROC and r = 0.758** for MBC) indicates that the changes in TOC content of soils is mainly influenced by the labile C pools and are the sensitive indicators of soil quality improvements. The AFSs, A. nepalensis in particular, can, therefore, be recommended as an alternative soil management strategy for food production, and for the maintenance of soil quality and agricultural sustainability

Aiming to achieve heavy metal adsorption in water and soil environments, a montmorillonite rich bentonite was graft-copolymerized with chitosan, and the obtained composite material was evaluated as a metal immobilizing agent for remediating metal contaminated soil. The graft-copolymerization reaction in the composite was confirmed by scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) techniques. Batch adsorption studies with varying experimental conditions, such as adsorbent amount, pH and metal concentration, were conducted to assess the metal adsorption capacity of the composite. The adsorption pattern followed the Langmuir isotherm model, and maximum monolayer capacity was 88.5, 72.9, 51.5 and 48.5 mg g-1 for Cu, Zn, Cd and Ni, respectively. Amendment of a contaminated soil with the composite enhanced the metal retention capacity by 3.4, 3.2, 4.9 and 5.6-fold for Cu, Zn, Cd and Ni, respectively, over unamended soil. The desorption percentage of metals from the composite treated soil was significantly lower than the unamended contaminated soil. The findings indicated that immobilization of heavy metals in soils could be achieved by the chitosan-bentonite, which would potentially be an inexpensive and sustainable environmental remediation technology.