Potential,constraints and applications of in vitro methods in improving grain legumes

Grain legumes, the important constituents of sustainability‐based cropping systems and energy‐limited vegetarian diets have long been the subject of scientific research. Tremendous technological strides were made in the so‐called orphan crops, in terms of both varietal improvement and generation of basic information. Despite recalcitrancy and high genotype dependency, in vitro culture techniques such as organogenesis, in vitro mutagenesis, embryo rescue and in vitro gene transfer have been deployed for improvement of several grain legumes and these played an important role in introgression of desirable genes from related and distant species and creation of additional genetic variability. Stable and reproducible regeneration protocols resulted in the development of genetically modified chickpea, pigeon pea, cowpea, mungbean, etc., while embryo rescue was deployed successfully for recovery of interspecific recombinants, a few of them exploited for the development of commercial cultivars. Nevertheless, doubled haploidy witnessed limited success and protoplast regeneration and in vitro mutagenesis remained of academic interest. The present review focuses on the progress, achievements, constraints and perspectives of using in vitro technology in grain legume improvement.     

Cryopreservation of silver barb Puntius gonionotus (Bleeker) spermatozoa: effect of extender composition,cryoprotective agents and freezing rate on their postthawing fertilization ability

The effects of extender composition, cryoprotectant concentration and freezing and thawing on the fertilization efficiency of cryopreserved spermatozoa of Puntius gonionotus were evaluated. Computer‐aided motility analysis of semen was conducted to check the suitability of spermatozoa for cryopreservation after mixing with different extenders and cryoprotective agents (CPAs). Extender‐4 with an osmolality 260 mOsmol kg⁻¹and pH 7.6 was used for the cryopreservation study. Among the CPAs, dimethyl sulphoxide (DMSO) was least toxic and more than 60% fertilization was achieved when used at 1.4 M at 0 °C for 10 and 30 min, whereas the toxicity of all CPAs to spermatozoa was evident when tested at 30 °C. Semen frozen at −16 °C min⁻¹ with 1.4 M DMSO showed 70% fertilization, which was significantly higher (P<0.05) than other freezing rates. Samples thawed at 35 °C water showed a fertilization rate comparable with that of fresh semen. Computer‐assisted semen analysis of fresh and frozen semen after thawing showed variations in different types of motility in spermatozoa and in their class. There was no significant difference in motility before or after cryopreservation; however, significant differences could be observed in the average path velocity (VAP), straight line velocity (VSL) and curve linear velocity (VCL). Semen of silver barb could be cryopreserved with extender‐4 by addition of 1.4 M DMSO to a final cryopreservation medium (MED 2) cooled at a rate of −16 °C min⁻¹, stored in liquid nitrogen (−196 °C) and utilized after thawing at 35±2 °C.     

Effect of dietary Curcuma longa on enzymatic and immunological profiles of rohu,Labeo rohita (Ham.), infected with Aeromonas hydrophila

The aim of this study was to evaluate the dietary dosages of turmeric that enhance immune response and disease resistance against the opportunistic pathogens Aeromonas hydrophila in Labeo rohita fingerlings. Hence, four different dosages of turmeric at 0.1, 0.5, 1.0 and 5.0 g kg^?1 feed were given to the fingerlings of L. rohita for 60 days at 4% body weight. At every 20‐day interval, different biochemical, haematological, enzymatic and immunological parameters of fish were evaluated. After 60 days, fish were challenged with A. hydrophila. The mortality (%) was recorded on the tenth day post challenge. Most of the immune parameters including lysozyme activity, superoxide anion production and serum bactericidal activity were significantly (P<0.05) higher on 60 days of feeding of 1.0 g of turmeric per kg of feed. Challenge study indicated 100% and 89% survivability in the group of fish fed with 5.0 and 1.0 g of turmeric per kg of feed respectively. Feeding of turmeric might have maintained long‐term protection in fish by elevating the nonspecific immune system such as Nitroblue tetrazolium (NBT), lysozyme and serum bactericidal activity. The result showed that turmeric at a dose of 1.0 g kg^?1 feed for 60 days provided the greatest protection to pathogen challenge.     

Integrated effect of population and weed management regimes on weed dynamics,performance, and productivity of basmati rice (<Emphasis Type="Italic">Oryza sativa</Emphasis> L.)

Weeds caused serious problem on yield reduction of basmati rice worldwide. Losses caused by weeds varied from one country to another, depending on the presence of dominant weeds and the control methods practiced by farmers; therefore, suitable plant population and weed management practices should be adopted. Keeping these in mind, a field experiment was carried out during kharif seasons of 2009 and 2010 at crop Research Centre of SVPUA&T, Meerut, India comprising 4 planting geometries, viz. 20, 30, 40, and 50 hills m^?2 as main plot factor, and 5 weed management practices (Butachlor @ 1.0 kg ha^?1, Butachlor @ 1.0 kg ha^?1 fb (followed by) one hand weeding, Butachlor @ 1.0 kg ha^?1 fb Almix @ 4 g ha^?1, two hand weedings and weedy check) in a split plot design with 3 replications. Experimental results revealed that plant population of 50 hills m^?2 proved superior over that of 20 hills m^?2 in respect of weed density, weed dry weight, number of tillers m^?2, yield attributes, grain, straw, and biological yields. The maximum grain yield (29.00 and 31.00 q ha^?1) and straw yield (51.30 and 52.50 q ha^?1) were recorded in 50 hills m^?2 followed by 40 hills m^?2 during 2009 and 2010, respectively. In respect of nitrogen, phosphorus, and potassium removal, a reverse trend was observed: the highest in 20 hills m^?2 followed by 30, 40, and 50 hills m^?2. As far as the weed management practices are concerned, both chemical and mechanical methods of weed control were found superior over weedy check. The lowest weed density, dry weight, and highest weed control efficiency, maximum length of panicle^?1, number of panicle (m²), and 1000-grain weight and grain yield of 30.40 and 32.60 q ha^?1 were recorded with two hand weedings which was at par with Butachlor @ 1.0 kg ha^?1 fb one hand weeding over rest of the weed management practices.     

Alteration in important quality traits and antioxidant activities in Brassica oleracea with Ogura cybrid cytoplasm

In vegetable brassicas, cytoplasmic male sterility (CMS) system is the most preferred mechanism for hybrid seed production and Ogura cybrid cytoplasm is the only source used widely. Effects of the alien cybrid cytoplasm on important quality traits need to be understood for their effective use in breeding programme. In analysing 38 Ogura cybrid cytoplasm‐based cauliflower CMS lines, it was revealed that introgression of Ogura cytoplasm resulted in significant alteration in important quality traits. Cupric reducing antioxidant activity and ferric reducing ability of plasma values were increased up to 5–10 times in different genotypes. Among 38 analysed CMS lines, concentration of plant pigments such as anthocyanin, total chlorophylls and ascorbic acid was reduced in 21, 17 and 32 genotypes, respectively. However, the concentration of total carotenoids and β‐carotene was elevated in most of the CMS lines and total carotenoid was increased up to 20 times in the CMS line, Ogu13‐85‐2A. The results indicate the role of nuclear–cytoplasmic interaction and mitochondrial genome in determining concentration of different quality traits.     

Extension of shelf life of tuberose flowers using a combination of gamma irradiation and generally regarded as safe (GRAS) preservatives and assessment of antimicrobial potency of senesced flowers

Tuberose cut flowers, available as loose flowers, were treated with gamma (γ) irradiation and generally regarded as safe (GRAS) preservative solutions for extension of shelf life. The flowers were packaged in low-density polyethylene bags, heat sealed and stored at 23 ± 2°C, 80% relative humidity (RH) and 4 ± 1°C, 40% RH, respectively. The flowers stored at these two temperature regimes were subjected to sensory evaluation and biochemical analyses. From these assessments, the longest shelf life of tuberose flowers was found to be 8 days at 23 ± 2°C, 80% RH (compared to 4 days for control) and 24 days at 4 ± 1°C, 40% RH (compared to 8 days for control) using combination treatment of low dose γ-irradiation (0.02 kGy) and preservative solutions (4% sucrose and 0.02% CaCl₂). Ethanolic extract of tuberose flowers of the most shelf stable set (stored at 4 ± 1°C), i.e. at the end of 24 days, showed antimicrobial potency against the common skin pathogen Staphylococcus aureus (ATCC 25923 and MDR strains), suggesting utility of the senesced tuberose flowers for therapeutic applications. This preservation technique would promote export of tuberose flowers by extension of their shelf lives and allow utilization of these flowers, post senescence.     

Earthworm biomass response to soil management in semi-arid tropical Alfisol agroecosystems

Earthworms recorded during 1989–1993 across 15 soil management treatments, comprising three different tillagexthree organic amendments (bare, farmyard manure, and rice straw) and six perennial ley treatments, belonged to two endogeic species, Octochaetona phillotti (Michaelsen) and Lampito mauritii Kinberg, while in a nearby undisturbed natural revegetation area three species were found, including the above two and Octonochaeta rosea (Stephenson). The earthworm biomass showed significant temporal and spatial variations and was higher during the post monsoon period than in the early rainy season. No worm biomass was recorded during the dry season. In the tillage and organic amendment treatments, the biomass was drastically reduced from September 1989 to September 1991 after the application of carbofuran and some herbicides, and was significantly reduced during these two years compared to that of 1992. The maximum monthly earthworm biomass ranged between 2.5 and 17.9 g m^-2 across the treatments and increased several-fold in the nearby natural revegetation area (75.9 g m^-2). It significantly increased in perennial ley treatments compared to annual treatments with organic amendments. Thus the earthworm biomass varied significantly (P<0.01) across the 15 treatments, indicating discernible effects of soil management.Visiting Scientist (under the Rockefeller Foundation Environmental Research Fellowship in International Agriculture)     

Methane emission from two Indian soils planted with different rice cultivars

In a greenhouse study, methane emissions were measured from two diverse Indian rice-growing soils planted to five rice cultivars under similar water regimes, fertilizer applications and environmental conditions. Significant variations were observed in methane emitted from soils growing different cultivars. Total methane emission varied between 8.04 and 20.92gm^–2 from IARI soil (Inceptisol) and between 1.47 and 10.91gm^–2 from Raipur soil (Vertisol) planted to rice. In all the cultivars, emissions from IARI soil were higher than from Raipur soil. The first methane flux peak was noticed during the reproductive phase and the second peak coincided with the grain-ripening stage of the rice cultivars. Received: July 7, 1996     

Response of the pigeonpea-Rhizobium symbiosis to salinity stress: variation among Rhizobium strains in symbiotic ability

Summary There were significant differences among pigeonpea [Cajanus cajan (L.) Millsp] Rhizobium sp. strains (IC 3506, IC 3484, IC 3195, and IC 3087) in their ability to nodulate and fix N₂ under saline conditions. Pigeonpea plants inoculated with IC 3087 and IC 3506 were less affected in growth by salinity levels of 6 and 8 dS m^-1 than plants inoculated with the other strains. For IC 3506, IC 3484, and IC 3195, there was a decrease in the number of nodules with increasing salinity, while the average nodule dry weight and the specific nitrogenase activity remained unaffected. However, in IC 3087, the number of nodules increased slightly with increasing salinity. Leaf-P concentrations increased with salinity in the inoculated plants irrespective of the Rhizobium sp. strain, and leaf-N concentrations decreased with increasing salinity in IC 3484 and IC 3195 only. Shoot-Na and-Cl levels were further increased in these salt-sensitive strains only at 8 dS m^-1. Therefore there may be scope for selecting pigeonpea Rhizobium sp. symbioses better adapted to saline conditions. The Rhizobium sp. strains best able to form effective symbioses at high salinity levels are not necessarily derived from saline soils.Submitted as JA No. 919 by the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT)