Deterioration of rhizospheric soil health due to elevated ultraviolet-B

Enhancements in ultraviolet-B radiation (UV-B) due to stratospheric ozone depletion affect biological forms directly and indirectly. To investigate how belowground processes are affected under increased UV-B, a field experiment with mung bean cultivars (HUM-1 and HUM-12) was conducted. The responses of selected soil enzymes (β-glucosidase, cellobiohydrolase, polyphenol oxidase, glycine aminopeptidase, and phosphatase), microbial biomass C and N were assessed in rhizospheric and non-rhizospheric zones, along with measurements of phenol and flavanoid contents in roots and leaves. Test plants were exposed to two UV-B levels: (1) UVB, simulating 20% stratospheric O₃ depletion; and (2) UV0, the ambient UV-B. Elevated UV-B depressed shoot biomass by 24.8 and 15.9% and root biomass by 43.7 and 38.4% in cv. HUM-1 and HUM-12 compared with UV0. Although elevated UV-B caused an increase in phenol and flavonoid contents in leaves and roots, a reduction in the number of root nodules (32.4 and 24% in HUM-1 and HUM-2, respectively) and their fresh weight (27 and 23% in HUM-1 and HUM-2, respectively) was observed. Elevated UV-B caused microbial activity to shift from the rhizosphere to non-rhizosphere as indicated by increased microbial biomass N and soil enzyme activities in this zone.     

Variation between and within lentil landraces from Yemen Arab Republic

Summary The variation in 31 landraces of lentil collected from Yemen Arab Republic was partitioned to estimate the variation between populations and the variation between families within populations by studying a total of 568 progenies of randomly selected plants. There was significant variation between populations and between families within populations in seedling pigmentation, time to flower, time to maturity and plant height, but the predominant source of variation was between populations. This variation was unrelated to altitude of collection. The landraces were equally variable across characters. The implications of this analysis of variation on lentil breeding and germplasm collection are discussed.     

Response of wheat genotypes to zinc fertilization for improving productivity and quality

Field experiments were conducted to evaluate the effects of zinc (Zn) fertilization on yield potentiality and quality of promising wheat varieties during winter seasons of 2013–14 and 2014–15 at the research farm of the Indian Agricultural Research Institute, New Delhi. Among genotypes, HD 2967 genotype proved as best in realizing the highest grain yield (4.89 Mg ha^?1), net returns and benefit–cost ratio besides increased protein (13.4%) and wet gluten (29.4%) content in grain. Highest grain Zn concentration and recovery efficiency (RE) recorded in HD 2851 and HD 2687, respectively. HD 2932 registered lowest grain hardiness index (GHI) followed by PBW 343, indicating their better bread-making quality. With respect to Zn fertilization, application of 1.25 kg Zn Zn–ethylene diamine tetra acetic acid (Zn–EDTA) + 0.5% foliar spray at maximum tillering and booting stages resulted in the highest yields, grain Zn concentration and RE followed by 2.5 kg Zn (ZnSO₄·7H₂O) + 0.5% foliar spray at both stages. These treatments are also superior most with respect to grain quality parameters such as protein, wet gluten and starch content. From profitability viewpoint, 2.5 kg Zn (ZnSO₄·7H₂O) + 0.5% two foliar sprays were most remunerative with maximum net returns and benefit–cost ratio.     

Development of controlled release formulations of carbofuran and evaluation of their efficacy against Meloidogyne incognita

Controlled release (CR) formulations of the insecti-nematicide carbofuran have been prepared using commercially available rosin, sodium carboxymethylcellulose and sodium carboxymethylcellulose with clay (bentonite, kaolinite, and Fuller's earth). The kinetics of carbofuran release in soil from the different formulations were studied in comparison with that of the commercially available granules (3G). Release from the commercial formulation was faster than with the new CR formulations. Addition of clay in the biodegradable polymer matrix reduced the rate of release. The diffusion exponent (n value) of carbofuran in soil ranged from 0.462 to 0.740 in the tested formulations. The half-release (t1/2) values ranged between 4.79 and 25.11 days, and the period of optimum availability (POA) of carbofuran ranged from 15.10 to 43.97 days. The mean EC50 of the commercial formulation against Meloidogyne incognita was quite high as compared to those of CR formulations. The effective duration (te) of carbofuran from the CR and commercial formulations was predicted by fitting the mean EC50 values of test formulations in the model (M(infinity) - Me)/M(infinity) = Kdte. It was 0.7 day in commercial 3G in comparison with 17.8 days for CMC-bentonite. The bioassay studies revealed that with the rosin-yellow polymer, the dose of carbofuran could be reduced to half of its recommended dose for nematode control. Overall, a comparison of CR formulations with the commercial one showed an earlier degradation of carbofuran in the latter and relatively prolonged activity in the former.     

Influence of Levels and Methods of Boron Application on the Yield and Uptake of Boron by Cotton in a Calcareous Soil of Punjab

A field experiment was conducted to study the influence of boron (B) application on yield and B uptake of cotton (Gossypium hirsutum L.) in B-deficient calcareous soil of south-west Punjab. The treatments comprise six levels of soil-applied B (0.0, 0.5, 1.0, 1.5, 2.0, and 2.5 mg B kg^?1soil) and two levels of foliar-applied B (0.1% and 0.2% borax and granubor solution) along with the common control (no B application). The experiment was laid out in RBD factorial design with three replications. The seed cotton yield and its attributing characters (plant height, number of sympodial and monopodial branches, boll weight, and number of boll per plant) and root biomass increased significantly with increasing levels of boron up to 1.0 mg B kg^?1 level over the control and then remained nonsignificant with further higher levels of soil-applied boron. Among foliar-applied boron levels, 0.1% borax solution was better than 0.2% borax solution. Soil-applied boron was at par with foliar-applied boron. The efficiency of borax and granubor was found to be equal in both sources of boron. The mean B content and its uptake by seed cotton and roots increased significantly up to 1.0 mg B kg^?1 soil-applied B level and then recorded nonsignificant with further higher levels of boron. For the foliar method of B application, the mean B content and its uptake by seed cotton increased significantly over the control. The mean available B content in soils (0–15 cm) at 45, 75, 105, and 145 days after sowing increased significantly over the control for all soil-applied B levels, while it remained nonsignificant over the control for all growth stages of cotton in foliar method of B application. Further, it was positively correlated with root biomass (r = 0.91), boron uptake by root (r = 0.98), and sympodial branch per plant (r = 0.81). The interaction of B application levels and sources was not significant for all studied traits. Regardless of B sources, B application had a significant effect on yield, yield attributes, and B uptake up to 1.0 mg B kg^?1 level for soil-applied B and 0.1% borax or granubor solution for foliar-applied B.     

Assessing soil properties and nutrient availability under conservation agriculture practices in a reclaimed sodic soil in cereal-based systems of North-West India

Soil quality degradation associated with resources scarcity is the major concern for the sustainability of conventional rice-wheat system in South Asia. Replacement of conventional management practices with conservation agriculture (CA) is required to improve soil quality. A field experiment was conducted to assess the effect of CA on soil physical (bulk density, penetration resistance, infiltration) and chemical (N, P, K, S, micronutrients) properties after 4 years in North-West India. There were four scenarios (Sc) namely conventional rice-wheat cropping system (Sc1); partial CA-based rice-wheat-mungbean system (RWMS) (Sc2); CA-based RWMS (Sc3); and CA-based maize-wheat-mungbean (Sc4) system. Sc2 (1.52 Mg m^?3) showed significantly lower soil bulk density (BD). In Sc3 and Sc4, soil penetration resistance (SPR) was reduced and infiltration was improved compared to Sc1. Soil organic C was significantly higher in Sc4 than Sc1. Available N was 33% and 68% higher at 0–15 cm depth in Sc3 and Sc4, respectively, than Sc1. DTPA extractable Zn and Mn were significantly higher under Sc3 and Sc4 compared to Sc1. Omission study showed 30% saving in N and 50% in K in wheat after four years. Therefore, CA improved soil properties and nutrient availability and have potential to reduce external fertilizer inputs in long run.     

Influence of Glomus–Rhizobium Symbiosis on Productivity,Root Morphology and Soil Fertility in Garden Pea in Himalayan Acid Alfisol

The influence of dual inoculation of arbuscular mycorrhizal fungi (AMF) and Rhizobium was assessed on garden pea productivity, root morphology and soil fertility during 2011–2012 at Palampur, India, in a medium phosphorus (P) acid Alfisol. Field experimentation comprised 13 treatments involving Rhizobium, AMF and inorganic fertilizers in (RBD) replicated thrice. The dual inoculation of Rhizobium and AMF exhibited nominal effect on pea pod length, pod girth and number of seeds per pod. However, average pod weight (APW) and productivity increased by 14.1 and 20% following dual inoculation, respectively, over generalized recommended nitrogen, phosphorus and potassium (NPK) dose general recommended dose (GRD). Dual inoculation of pea seed with both symbionts sharply increased the root volume (RV), root dry weight (RDW), root weight density (RWD) and root nodules per plant by 34.5, 13.3, 13 and 44%, respectively. Similarly, the highest AMF root colonization was registered under dual-inoculated plots compared to sole application of Rhizobium or AMF. Different treatments including dual-inoculated ones did not alter the soil organic carbon (SOC), available N, K and diethylenetriaminepentaacetic acid (DTPA)-extractable micronutrients iron, zinc, copper and manganese (Fe, Zn, Cu and Mn) status significantly; however, a nominal buildup in the above-mentioned parameters was registered under dual inoculation. Available P status increased to the tune of 6.7 and 8.7% following dual inoculation with Rhizobium and AMF over their respective sole inoculations. Overall, the current study suggests that Glomus–Rhizobium symbiosis has great potential in enhancing productivity through better proliferation of the root system and improved soil fertility status. Furthermore, dual inoculation of AMF and Rhizobium can save up to 25% fertilizer N and P in garden pea in acid Alfisol of the northwestern Himalayas (NWH).     

Influence of AM fungi,inorganic phosphorus and irrigation regimes on plant water relations and soil physical properties in okra (Abelmoschus esculentus L.) – pea (Pisum sativum L.) cropping system in Himalayan acid alfisol

Present investigation studied plant water relations and soil physical properties through AM fungi (Glomus mosseae) to mitigate drought stress in Himalayan acid Alfisol having low water retentivity. Experimentation was carried out at Palampur, India during 2009–2011 in okra–pea cropping system in randomized block design (RBD) replicated thrice with 14 treatments comprising arbuscular mycorrhizal (AM) fungi, varying phosphorus nutrition and irrigation regimes at 40 and 80% available water holding capacity. Integrated use of AM fungi at varying phosphorus (P) levels and irrigation regimes led to significantly higher relative leaf water content (3% each) in okra and pea besides significantly higher xylem water potential (27%) in pea over non-AM fungi counterparts. AM fungi enhanced water-use-efficiency in okra (5–17%) and pea (12–35%) over non–AM fungi counterparts. AM fungi also improved water holding capacity (5–6%) and mean weight diameter of soil particles (4–9%) over non–AM fungi counterparts; but, had nominal or no effect on bulk density. Mycorrhizal plants maintained higher tissue water content imparting greater drought resistance to plants over non–mycorrhizal plants at moisture stress. It is inferred that integrated application of AM fungi and P at varying irrigation regimes improved the plant water relations vis-à-vis drought resistance, crop productivity, WUE, soil aggregation and water holding capacity in okra–pea sequence in Himalayan acid Alfisol.     

Morpho-physiological evaluation of Elymus semicostatus (Nees ex Steud.) Melderis as potential donor for drought tolerance in Wheat (Triticum aestivum L.)

Genetic Resources and Crop Evolution - Gradual deterioration in water resources and unpredictable distribution pattern of annual precipitation amount are major threats having drastic effects on...     

Population structure,gene flow and genetic diversity analyses based on agro-morphological traits and microsatellite markers within cultivated and wild germplasms of okra [Abelmoschus esculentus (L.) Moench.]

Genetic Resources and Crop Evolution - Okra [Abelmoschus esculentus (L.) Monech.] is an annual herb of the family Malvaceae and has tremendous nutritional and industrial potential. However, the...