Balwinder Kumar

Mechanism of Zinc absorption in plants: uptake, transport, translocation and accumulation

Zinc (Zn) is an essential micronutrient for plants and animals. Unfortunately, deficiency of Zn in humans has increased on a global scale. The main reason of this micronutrient deficiency is dietary intakes of food with low Zn levels. Adoption of biofortification approaches would result in Zn enrichment of target tissue to a considerable extent. However, there is a basic need to understand Zn absorption mechanisms in plants prior to exploitation of such practical approaches. Zn absorption is a complex physiological trait which is mainly governed by Zn transporters and metal chelators of plant system. Plant growth stage, edaphic factors, season etc. also influence Zn efficiency of particular species. Molecular studies in Zn hyperaccumulators have already demonstrated the participation of specific Zn transporters, vacuolar sequestration and detoxification mechanisms in maintenance of Zn homeostasis. These have been described in detail in present review and provide opportunities for utilization in biofortification programmes. However, issues such as lesser bioavailability of Zn in target organ, uptake of toxic divalent cations (Cd, Ni, Pb, As etc.) along with Zn, sink activity and dilution in Zn concentration in response to sink number etc. in biofortified crops need further investigation. In order to design novel strategy in biofortification programmes, future researches should focus on physiological performance and yield penalties in concerned crop, metabolic load in term of organic acid production and crosstalk of Zn with other mineral nutrients under low and high Zn conditions.

Growth and productivity of wheat affected by phosphorus-solubilizing fungi and phosphorus levels.

Phosphorus (P) availability limits crop growth in most of cultivable soils in north-west India. The beneficial rhizosphere microorganisms such as phosphate-solubilising fungi (PSF) were found to increase P availability in soil and improve crop yields. In view of this, field experiments were conducted during 2009-2011 to evaluate the effect of seed inoculation with PSF ( Penicillium bilaii ) at different rates of fertilizer P on P content in leaves and grain yield of irrigated wheat in India. The soil was low in Olsen P at the Bathinda site and medium at the Ludhiana site. In no-P treatment, PSF significantly increased grain yield by 12.6% over non-inoculated control. The effect of PSF on grain yield was generally more pronounced in a soil with low Olsen-P compared to medium Olsen-P level. Inoculation of PSF along with 50% P fertilizer increased wheat yield equivalent to 100% P with no PSF. Spike density was significantly higher in PSF + 50% P than all the other treatments. There is need to study a long-term effect of Penicillium bilaii on P-fertilizer saving in wheat on soils varying in P availability, pH and P fixation capacity for different wheat-based cropping systems.

Fodder Quality of Maize: Its Preservation

Green fodder is an important component of animal husbandry. The growth of dairy sector primarily depends upon the availability of nutritious fodder. Maize is one of the most nutritious non-legume green fodders. The high acceptability of maize as fodder can be judged from the fact that it is free from any anti-nutritional components. Maize is quick growing, yields high biomass, and is highly palatable. It contains sufficient quantities of protein and minerals and possesses high digestibility as compared to other non-legume fodders. It contains high concentrations of soluble sugars in the green stage, which makes it most fit for preservation as silage. The abundance of green fodder due to increasing cultivation of specialty corn could greatly help in boosting the prospects of dairy sector in the peri-urban regions of the country.

Biofortified Wheat for Mitigating Malnutrition

Zinc, iron, and provitamin A are the critical micronutrients required for structural and functional integrity of biological system. Their deficiency affects billions of people worldwide, by hampering growth and development and destroying the immune systems. Micronutrient-dense wheat (Triticum aestivum L.) varieties can be developed by using the existing genetic variability in the germplasm. Even with new screening tools such as gene discovery, marker-assisted selection, and precision phenotyping, selection of high-Zn genotypes would appear an easy task. Wide genetic variation available in primitive and wild relatives, landraces, and synthetic hexaploids is now being intensively exploited under HarvestPlus program to identify quantitative trait loci (QTLs) for enhancing concentration of Zn and its bioavailability in wheat grain. Further regulation of gene expression in identified QTLs in response to biotic and abiotic stresses is also analyzed. The ultimate goal of this program is to improve nutritional status of wheat cultivars. However, enhancement of Zn uptake through utilization of genetic variation would be possible only when the soil environment (i.e., mineral composition) has sufficient zinc pool for absorption. The varieties like BHU 1, BHU 17, and BHU 19 from India and NR 419, NR 420, and NR 421 from Pakistan show 4–10 ppm increase in grain zinc. Agronomic biofortification strategies through application of Zn-containing fertilizer provide an immediate and effective option to increase grain Zn concentration and productivity in wheat, particularly in areas of severe nutrient-deficient soil. Zn fertilizer can be used along with the pesticide used to control aphids or yellow rust in wheat. Fertilizer application strategies must be practical and economically feasible. However, in developing countries where resource-poor farmers cannot afford fertilizer, breeding for mineral density may remain the sole agricultural intervention to improve the nutritional content of staple crops.

Herbage production, nutritional composition and quality of teosinte under Fe fertilization.

Animal husbandry is integral part of subsistence farming for small holder farmers but non availability of good quality fodder for feeding to the livestock is major hurdle for dairy industry in South Asia. Micronutrients such as Fe deficiency in soil affect yield and quality of forage crops severely. This study was conducted for two consecutive years (2012 and 2013) to examine the effect of foliar spray of FeSO4 on the development, herbage yield, nutritive composition and quality of teosinte grown in Fe deficient alkaline field. The experiment was conducted in Randomized Block Design with set of seven treatments viz. two foliar sprays of 0.5, 1.0 and 2.0% FeSO4 at 30, 37 DAS and three foliar sprays of 0.5, 1.0 and 2.0% FeSO4 at 30, 37 and 44 DAS. An additional treatment with recommended dose of fertilizer along with foliar spray of deionized water was kept as control. The results of this study revealed an increase of 29.6 to 32.6% in green herbage yield (GHY) and 53.3 to 60.8% in dry matter yield (DMY) with 1.0 and 2.0% foliar sprays of FeSO4 at 30, 37 and 44 DAS over control. Fe foliar spray enhanced nitrogen (N), phosphorus (P), potash (K) and iron (Fe) content of herbage, however Mn content decreased due to antagonism. Increased herbage quality and estimated digestibility parameters like crude protein (CP), total digestible nutrients (TDN), digestible dry matter (DDM), digestible crude protein (DCP), dry matter intake (DMI), relative feed value (RFV), relative forage quality (RFQ), net energy for lactation (NEL), digestible feed energy (DFE) and reduction in fibers were recorded with three 1.0% foliar sprays of Fe. Gross return, net field benefit (NFB), benefit cost ratio of teosinte crop improved with foliar Fe application. Maximum rate of returns (400%) were recorded with three 1.0% FeSO4 at 30, 37 and 44 DAS. Thus, we conclude that three foliar sprays of 1.0% FeSO4 enhanced the teosinte growth, yield and quality which will certainly improve livestock production.

Resource-Conserving Technologies for Enhancing Resource Use Efficiency and Crop Productivity

Declining soil, water and human resources in rice-wheat and other irrigated cropping systems need the resource-conserving technologies (RCTs) for agricultural sustainability. After the era of green revolution, the use of soil and water resources is overexploited. The income from irrigated agroecosystem especially from rice-wheat system is declining in many areas as cultivation costs are rising faster than crop prices. The various RCTs can save soil, water and other natural resources. Zero tillage with or without mulch/happy seeder sowing technology not only saves the money spent on inputs but also gives similar or higher grain yields in various crops by conserving soil moisture but also reducing the weed density and environmental pollution. Furrow-irrigated bed planting/permanent raised-bed technologies can be practices for sustainability of major cropping systems. Hydrogel (water-adsorbing material) can effectively be used under rainfed/dryland or limited water conditions for increasing the water use efficiency. Direct seeding of rice with seed-cum-fertilizer drill under well-levelled conditions holds the promise of saving water and human resources. Human resources are decreasing due to industrialization, so direct seeding or mechanical transplanting of rice is the best solution. Laser land levelling can save huge amount of the irrigation water for getting similar productivity as in conventionally levelled fields. As the machinery required for adoption of these RCTs are heavy and costly, these machines should be used on co-operative basis.