Hybridization and in vitro culture of an orchid hybrid Ascocenda ‘Kangla’

The present study focuses on hybridization program involving two species belonging to two different vandaceous genera, viz., Ascocentrum ampullaceum (Roxb.) Schltr. var. auranticum, a narrow endemic orchid of Manipur and Vanda coerulea Griff., an endangered orchid of Appendix I of CITES (Convention on International Trade in Endangered Species of Wild Fauna and Flora), to synthesize the primary hybrid genus with intermediate and improved characters in the F₁ generation. Observations on the crossability in the present bigeneric cross between V. coerulea and A. auranticum had been achieved with 60% success when V. coerulea was taken as female parent. Murashige and Skoog (MS) basal medium at half-strength was effective for the development of the hybrid seedlings of V. coerulea × A. auranticum followed by Vacin and Went (VW) and Knudson C (KC) media. The best response of seedling growth was observed on MS medium at half-strength supplemented with 2.3 μM kinetin + 0.5 μM α-naphthalene acetic acid with maximum shoot height (2.7 cm), leaf number (4.6) and root number (4.1) after 150 days of inoculation. The survival percentage and growth performance of the seedlings were found to be higher (80% survival) in potting substrate consisting of brick:charcoal in the ratio 2:1 mulched with moss (Sphagnum sp.) than in potting substrate consisting of brick:charcoal:tree fern in the ratio 2:1:1. The first flowering was observed in the hybrid seedlings of V. coerulea × A. auranticum after 2 years of transfer to the ex vitro environment. Morphologically, the flowers differed from that of the parents clearly showing the success of the hybridization experiment. Registration of the hybrid has been made with the Royal Horticultural Society with the nomenclature Ascocenda ‘Kangla’ (No. T128725).     

Clonal propagation of triploid <Emphasis Type="Italic">Acorus calamus</Emphasis> Linn. Using dual-phase culture system

Acorus calamus is an important medicinal plant which has been used in Indian traditional medicine since time immemorial. Various bioactive molecules, viz., acorin, α- and β-asarone, asaryldehyde, caryophylene, isoasarone, methylisoeugenol, and safrol have been isolated from this plant. However, the use of this plant for medicinal purpose has been recently banned due to the high toxic property of β-asarone. The triploid Acorus calamus is reported to be low in β-asarone content and thus found to be the ideal raw material for medicinal use. The present investigation represents our finding for successful in vitro clonal propagation of the elite triploid accessions of Acorus calamus for mass propagation. In the dual-phase culture system consisting of agar-solidified Murashige and Skoog medium overlaid by liquid fraction of the same medium, maximum multiple shoot induction was favored by supplementation of α-naphthaleneacetic acid (0.5 mg L⁻¹) and 6-benzylaminopurine (2.0 mg L⁻¹). In vitro rooting of the microshoots was maximum in the medium supplemented with indolebutyric acid at 2.0 mg L⁻¹. The well-rooted microshoots could be successfully hardened and transplanted in the field. This result can be reproduced and is a viable protocol for successful clonal propagation of the seedless triploid Acorus calamus for conservation and sustainable development.     

Seroprevalence of Peste des petits ruminants in cattle and buffaloes from Southern Peninsular India

This study describes seroprevalence of Peste des petits ruminants (PPR) in cattle and buffaloes carried out during the period 2009–2010 using the randomly collected serum samples from different parts of Southern peninsular India. The report presents the results of PPR virus (PPRV)—specific antibodies in situations where either the subclinical or inapparent or non-lethal infection was there in cattle and buffaloes. A total of 2,548 serum samples [cattle = 1,158, buffaloes = 1,001, sheep = 303 and goat = 86] were collected and screened for PPRV antibodies by using a PPR monoclonal antibody-based competitive ELISA kit. Analysis of 2,159 serum samples indicates an overall 4.58% prevalence of PPRV antibody in cattle and buffaloes. The presence of PPRV-specific antibodies demonstrates that cattle and buffaloes are exposed to PPR infection naturally, and the transmission mode may be direct or indirect. Further, it implies the importance of bovines as subclinical hosts for the virus besides widespread presence of the disease in sheep and goats in the country.     

Identification of drought responsive QTLs during vegetative growth stage of rice using a saturated GBS-based SNP linkage map

Drought is a major abiotic constraint for rice production worldwide. The quantitative trait loci (QTLs) for drought tolerance traits identified in earlier studies have large confidence intervals due to low density linkage maps. Further, these studies largely focused on the above ground traits. Therefore, this study aims to identify QTLs for root and shoot traits at the vegetative growth stage using a genotyping by sequencing (GBS) based saturated SNP linkage map. A recombinant inbred line (RIL) population from a cross between Cocodrie and N-22 was evaluated for eight morphological traits under drought stress. Drought was imposed to plants grown in 75 cm long plastic pots at the vegetative growth stage. Using a saturated SNP linkage map, 14 additive QTLs were identified for root length, shoot length, fresh root mass, fresh shoot mass, number of tillers, dry root mass, dry shoot mass, and root-shoot ratio. Majority of the drought responsive QTLs were located on chromosome 1. The expression of QTLs varied under stress and irrigated condition. Shoot length QTLs qSL1.38 and qSL1.11 were congruent to dry shoot mass QTL qDSM1.38 and dry root mass QTL qDRM1.11, respectively. Analysis of genes present within QTL confidence intervals revealed many potential candidate genes such as laccase, Calvin cycle protein, serine threonine protein kinase, heat shock protein, and WRKY protein. Another important gene, Brevis radix, present in the root length QTL region, was known to modulate root growth through cell proliferation and elongation. The candidate genes and the QTL information will be helpful for marker-assisted pyramiding to improve drought tolerance in rice.     

Identifying important biophysical and social determinants of on-farm tree growing in subsistence-based traditional agroforestry systems

Many expert-designed agroforestry projects enunciated in 1970s around the world, particularly in the developing countries, had uneven success due to inadequate adoption or abandonment after adoption. There are many empirical studies on factors affecting on-farm tree cultivation mainly where expert-designed agroforestry programmes were introduced but lacking in case of traditional agroforestry. Moreover, the concern to identify key factors influencing on-farm tree growing is gaining importance. The present study identifies key factors in on-farm tree growing based on investigation of traditional agroforestry using logistic regression approach. The study is based on household survey of 401 households located in Indian Western Himalaya. The factors affecting on-farm tree growing were grouped into: biophysical (included land use and infrastructural aspects) and social. Models predicting on-farm tree growing for each category were developed and key factors affecting on-farm tree growing in the respective category were identified. A composite model was also developed by combining biophysical and social factors. In the present study, farm size, agroclimatic zone, soil fertility, mobility and importance of tree for future generations respectively were the key factors which influenced tree growing. In contrast to many previous studies which considered either biophysical or social factors, the composite model in the present study reveals that both biophysical and social factors are simultaneously important in motivating the farmers to grow trees on their farms in traditional agroforestry. Moreover, the present study open vistas for using farmers’ experience and knowledge of adoption of agroforestry to stimulate on-farm tree growing. The wider implication of the study is that biophysical as well as social variables should be considered together in designing suitable agroforestry systems in various parts of the world.     

In vitro culture of immature seed for rapid generation advancement in tomato

The importance of fast-trackt generation advancement in developing superior germplasm has been recognized in breeding of many crop species. To address this issue in tomato, immature seeds were excised from fruit at different maturity stages and transferred to culture medium. The best culture medium was modified full strength Moorashige–Skoog (MS) salts supplemented with 0.1 mg l⁻¹ IAA, 0.5 mg l⁻¹ IBA, 0.5 mg l⁻¹ GA₃ and 2% sucrose. If the excised seeds were able to grow, most showed shoot formation after a week. Seeds extracted as early as 10 days after pollination were successfully cultured provided they were transferred aseptically and without injury. No morphological or physiological changes in regenerated plants and their fruit relative to the parent were detected. Germination from immature seeds of tomato is a simpler alternative to in vitro culture of immature embryos or callus, as it can be undertaken in comparatively less stringent laboratory conditions. Using this approach, five generations can be produced in a year in contrast to a maximum of three generations with conventional methods. This offers an opportunity for rapid generation advancement aimed towards population development when coupled with marker assisted selection in tomato breeding for biotic and abiotic stress tolerance.     

Response to lime and P by several genetic sources of corn (Zsa mays L.) on a low pH and P soil in the greenhouse 1

The objective of this study was to investigate the response of 16 different genetic sources of corn (Zea mays L.) to lime and P application on a low pH and P Parsons silt loam soil in the greenhouse. A highly significant lime x P interaction was found for both dry matter production and P concentration. Phosphorus increased both dry matter production and P content of plant tissues with or without lime application. However, liming produced a detrimental effect when P was applied but no effect when no P was applied. Corn genetic sources showed a highly significant interaction with P treatment, but not with lime for both dry matter production and P concentration. The results suggest that improvement in corn growth could be achieved in a low P soil environment by genetic selection.     

Genotypic variation in partitioning of phosphorus in relation to nitrogen and dry matter during wheat grain development

Phosphorus has many similarities to N for plant nutrition, but little is known regarding P partitioning among genotypes and factors that affect it. Experiments were conducted to measure variation in partitioning of P and its relationship to N, dry matter, and yield components of wheat (Triticum aestivum L.). Sixteen cultivars grown under field conditions were sampled at anthesis for P, N, and dry matter and at maturity for the same constituents and for yield components. Relationships among the traits were determined by Spearman rank correlation coefficients. Accumulation of P and dry matter during grain development and grain HI, NHI, and PHI differed significantly among genotypes. Post‐anthesis P, N, and dry matter accumulation correlated positively as did HI, NHI, and PHI, but accumulation of the constituents was not related to their His. The positive associations were attributed to requirement of P and N for growth and their accumulation as reserve compounds in grain. Genotypic variation in PHI may be as useful as variation in HI and NHI for wheat improvement.     

Effects of Soil Type and Cover Condition on Cryptosporidium parvum Transport in Overland Flow

Overland transport kinetics of pathogens is controlled, in large part, by soil and vegetation. With an increasing number of concentrated animal operations, there is becoming a greater need to dispose of a vast amount of manure in a single, localized area. Animal manure contains a substantial amount of microbial pathogens, including Cryptosporidium parvum that may pose a threat of contamination of water resources. This study examines the kinetics of C. parvum in overland transport and critical factors involved in the design of best management practices, especially vegetative filter strips, to prevent the transport of harmful pathogens to water bodies. Three soil types were tested (Catlin silt-loam, Alvin fine sandy-loam, Darwin silty-clay), spanning the entire spectrum of typical Illinois soils. A 20-min rainfall event was produced using a small-scale (1.07 m?×?0.66 m) laboratory rainfall simulator over a soil box measuring 0.67 m?×?0.33 m. Each soil type was tested for pathogen transport kinetics with bare surface conditions as well as with smooth brome and fescue vegetative covers. Surface runoff, soil cores, and near-surface runoff were each analyzed for infective C. parvum oocysts using cell culture infectivity assays. Results showed that vegetation greatly reduced the recovery of infective oocysts, in addition to delaying the time to the peak recovery. However, there was no clear evidence of any one vegetation type being advantageous over another. The bare soil experiments resulted in a higher recovery of C. parvum oocysts from the Darwin soil compared to other two soils. Analyses of soil cores show a slightly higher recovery of oocysts in the Catlin soil compared to Alvin or Darwin soils.     

Yield, water-use efficiencies and root distribution of soybean, chickpea and pumpkin under different subsurface drip irrigation depths and oxygation treatments in vertisols

Most trickle irrigation in the world is surface drip yet subsurface drip irrigation (SDI) can substantially improve irrigation water use efficiency (IWUE) by minimizing evaporative loss and maximizing capture of in-season rainfall by the soil profile. However, SDI emitters are placed at depths, and in many soil types sustained wetting fronts are created that lead to hypoxia of the rhizosphere, which is detrimental to effective plant functioning. Oxygation (aerated irrigation water) can ameliorate hypoxia of SDI crops and realize the full benefit of SDI systems. Oxygation effects on yield, WUE and rooting patterns of soybean, chickpeas, and pumpkin in glasshouse and field trials with SDI at different emitter depths (5, 15, 25, and 35 cm) were evaluated. The effect of oxygation was prominent with increasing emitter depths due to the alleviation of hypoxia. The effect of oxygation on yield in the shallow-rooted crop vegetable soybean was greatest (+43%), and moderate on medium (chickpea +11%) and deep-rooted crops (pumpkin +15%). Oxygation invariably increased season-long WUE (WUE_sl) for fruit and biomass yield and instantaneous leaf transpiration rate. In general, the beneficial effects of oxygation at greater SDI depth on a heavy clay soil were mediated through greater root activity, as observed by general increase in root weight, root length density, and soil respiration in the trialed species. Our data show increased moisture content at depth with a lower soil oxygen concentration causing hypoxia. Oxygation offsets to a degree the negative effect of deep emitter placement on yield and WUE of SDI crops.