Genetic structure and diversity of India hybrid tea

The most important evolutionary event in the success of commercial tea cultivation outside China in ~30 countries came about by the origin of India hybrid tea in India, derived from the extensive spontaneous hybridization that took place between the Assam type tea growing in the forest regions of Assam, North-East India and China type tea introduced from China in ~1875 to many regions of North-East India. The release of an enormous pool of vigorous and highly variable plants of India hybrid tea in North-East India was a significant step forward for the origin and evolution of tea as a highly successful crop plant. The 1,644 accessions and clones of India hybrid tea, representatives of known 15 morphotypes, were screened by 412 AFLP markers amplified by 7 AFLP primer pair combinations. All the 412 genetic loci were polymorphic across the 1,644 accessions and clones. The analysis was done with distance (PCoA and NJ) methods, and the STRUCTURE (Bayesian) model. Both PCoA and NJ analysis clustered 1,644 tea accessions and clones into six major groups with one group in each, constituted mostly by China hybrid, Assam China hybrid and Assam hybrid morphotypes, of distinct genetic identity. No group was exclusive for any particular morphotype. The accessions and clones belonging to morphotypes, Assam type, Assam hybrid, China hybrid and China Cambod were distributed in all the groups. It is the Assam type/Assam hybrid morphotypes which exhibit much broader genetic variability than in China type/China hybrid/Cambod type/Cambod hybrid morphotypes. The STRUCTURE analysis inferred 16 populations (K = 16), for which the greatest values of probability were obtained. Nine of the 16 clusters were constituted by the tea accessions and clones of ‘pure’ ancestry. The remaining clusters were of ‘mixed’ ancestry. This analysis provides evidence that the accessions and clones of the same morphotype are not always of same genetic ancestry structure. The tea accessions and clones obtained from outside North-East India shared the same groups (distance method) and clusters (STRUCTURE model) which were constituted by North-East India accessions. The present study also demonstrates very narrow genetic diversity in the commercial tea clones vis-à-vis the profound genetic diversity existing in the tea accessions. These clones were distributed in hardly two of the six groups in NJ tree. The identified 105 core accessions and clones, capturing 98% diversity, have their origin from almost all groups/subgroups of NJ tree.     

A Modified Viborg's Triangle Approach for Surgical Drainage of Guttural Pouches Empyema Through Placement of a Fenestrated Tube in a Mare

A 7-year-old mare was brought to the clinic with a history of falling 1 month earlier and bilateral mucosanguinous nasal discharge, respiratory distress, and bilateral swelling caudal to the posterior margin of vertical rami of mandibles for 3 weeks. Lateral radiography of the neck region revealed gas-filled soft tissue density caudal to the mandibles. Empyema of the guttural pouches was diagnosed and surgical drainage was planned by placement of a fenestrated tube. A skin incision was made at the dependent part of the swelling in Viborg's triangle on both sides; guttural pouches were exposed and mucosanguinous contents drained by lancing the pouches. Fenestrated tubes, prepared from the tubing of a urine collection bag, were fixed into the guttural pouches by anchoring to the wall of the pouches and skin. Postoperatively, 5 g of streptomycin plus 4 million IU of penicillin and 75 mg of meloxicam were administered intramuscularly for 7 days and 5 days, respectively. Guttural pouches were lavaged daily with 0.1% potassium permanganate solution (KMnO₄) and 5% topical povidone iodine diluted with normal saline solution to 1%. Tubes from both sides were removed on the 14th postoperative day, and wounds healed by second intention. The animal recovered uneventfully.     

A less-known vegetable melon landrace “Arya” (<Emphasis Type="Italic">Cucumis melo</Emphasis> L.) from Rajasthan and Haryana,India: morphological,biochemical and taxonomic study

A less-known landrace of vegetable melon locally called “Arya” (Cucumis melo L.) known for drought tolerant trait was collected from two districts of Rajasthan and Haryana, India. Study was undertaken for preliminary morphological evaluation, biochemical and organoleptic test. A comparative study with snake melon was presented with field identification traits along with cultural practices and economic uses. The work aims at facilitating germplasm collection, detailed evaluation and systematic study on this valuable material with the prospects of crop diversification and value addition.     

Effect of Mixing Pine Needles Litters on Soil Biological Properties and Phosphorus Availability in Soil Amended with Fertilizers and Manures

Effect of different manures and pine needles application on soil biological properties and phosphorus availability was evaluated in sandy loam soils. Fertilizers nitrogen, phosphorus, and potassium (NPK); Sesbania aculeata green manure (GM); farm yard manure (FYM); and vermicompost (VC) were applied alone or in combination with pine needles. Microbial biomass carbon, dehydrogenase, and alkaline phosphatase activity increased significantly due to manures and NPK. Pine needles reduced the microbial biomass carbon (MBC) and dehydrogenase activity in FYM and VC but increased in NPK and GM. Acid phosphatase activities were found to be significantly increased by pine needles application in NPK, FYM, VC, and GM as compared to without pine needles counterparts. No significant differences were found in soil solution phosphorus in manure treated soil due to pine needle application, but phosphorus uptake was reduced significantly in these treatments. Pine needles application clearly influenced the soil biological properties without any perceptible effect on nutrient release from the manures.     

Detection and inheritance of leaf rust resistance in common wheat lines Agra Local and IWP94

Genetic studies were undertaken to determine the number and identities of leaf rust resistance genes in common wheat lines Agra Local and IWP94. The infection type arrays of the two lines with eight pathotypes (pt.) of P. triticina were different from those of lines possessing known leaf rust resistance (Lr) genes. Agra Local possessed two recessive resistance genes, one conditioning resistance to pathotype 4R9-7, and the other, a temperature-sensitive factor, gave resistance to pt. 121R127 at high temperature (27°C). IWP94 was previously demonstrated to carry Lr23. From the present study IWP94 was determined to have at least four leaf rust resistance genes. The first of these was the same recessive gene conferring resistance to pathotype 4R9-7 which was found in Agra Local. A second partially dominant gene conferred resistance to pathotype 121R127 at high temperature and two additional recessive genes governed resistance to pathotype 93R15. When present together, these two recessive genes complemented each other and provided resistance to pathotype 69R13 as well. One of the two recessive genes conferring resistance to pathotypes 93R15 and 69R13 was Lr23.     

Apple stem grooving virus naturally infects Himalayan wild cherry (Prunuscerasoides D. Don)

Himalayan wild cherry (Prunus cerasoides), widely distributed in the Himalayas, was found to exhibit severe virus‐like symptoms (chlorotic spots, chlorosis along the margins of the leaf and necrotic spots). Of 47 symptomatic and asymptomatic leaf samples tested through DAS‐ELISA, dot‐blot hybridization and RT‐PCR, only three were found to be positive for Apple stem grooving virus (ASGV) infection. The complete coat protein gene from all the three positive samples was molecularly characterized and sequencing of the amplicons confirmed presence of the virus. The three characterized isolates of Himalayan wild cherry (HWC‐15, HWC‐16 and HWC‐47) grouped with the ASGV apple isolates from India, Brazil and China. Of the three, two isolates (HWC‐15 and HWC‐47) shared around 100% sequence identity among themselves while 96.2% with the third isolate (HWC‐16) (both at nucleotide and amino acid level), respectively. While they all shared an overall identity of around 92.8–99% at (aa) and 86.5–99.5% at (nt) with rest of the isolates from different hosts and geographical locations. Experimental host range of the variant HWC‐16 isolate identified C. amaranticolor, C. sativus, C. quinoa, P. vulgaris, N. benthamiana and N. glutinosa as positives for the ASGV isolate‐inducing epinasty, symptomless carrier, chlorotic spots, interveinal chlorosis, chlorotic spots and chlorotic patch. To the best of our knowledge, this is a first report of natural infection of ASGV on Himalayan wild cherry.     

QTL Analysis of Late Blight Resistance in a Diploid Potato Family of Solanum spegazzinii × S. chacoense

Several quantitative trait loci (QTL) for resistance to late blight have been reported in diploid potatoes. The diploid wild potato species Solanum chacoense possesses a high degree of horizontal resistance to late blight. In the present study, we report on QTL mapping for late blight resistance in a diploid mapping population of 126 F₁ of Solanum spegazzinii (susceptible) × S. chacoense (resistant). The area under the disease progress curve (AUDPC) values for late blight resistance using the “whole plant in vitro assay” and the “detached leaf assay” on the mapping population displayed quantitative variation. Out of 64 AFLP primer-pairs combinations and SSR markers, a total of 209 significant AFLP loci were placed onto the 12 linkage group of potato covering a total map length of 6548.1 cM. QTL analysis based on the AUDPC dataset of the “whole plant in vitro assay” using the interval-mapping option identified two QTL (LOD?>?2.5) located on linkage groups IX and X, which explained 14.70 and 3.40% variation, respectively. The present study revealed the presence of potential new genetic loci in the diploid potato family contributing to quantitative resistance against late blight.     

Primary particle size distribution of eroded material affected by degree of aggregate slaking and seal development

Primary particle size distribution (PSD) of eroded sediment can be used to estimate potential nutrient losses from soil and pollution hazards to the environment. We studied eroded sediment PSDs from three saturated soils, packed in trays (20 × 40 × 4 cm), that had undergone either minimal aggregate slaking (MAS) or severe aggregate slaking (SAS) prior to a 60 mm simulated rainstorm (kinetic energy, 15.9 kJ m⁻³; droplet diameter, 2.97 mm) and collected runoff at regular intervals. The degree of aggregate slaking was controlled by the rate at which soils were wetted to saturation. The PSDs of eroded materials and of parent soils were determined using a laser particle size analyser. For each soil, PSD frequency curves of eroded sediments and parent soils were generally of a similar shape but most eroded sediments had larger clay contents than their parent soils. In the SAS treatment, cumulative clay enrichment in the eroded materials was inversely related to the parent soil clay content, these being 28.5, 26.6 and 22.8% richer in clay than their parent soils for the loam, sandy clay and clay, respectively. Generally, total clay loss was greater from soils with SAS than from those with MAS because of erosion rates; however, clay enrichment of sediments, compared with parent soil clay contents, was mostly greater in samples with MAS. Greater clay enrichment took place during the early seal development stage in the loam, but could not readily be associated with specific stages of seal development for the clay. In the sandy clay, the relation between seal development and clay enrichment in the eroded material depended on the initial degree of aggregate slaking. The observed large preferential loss of clay by erosion in cultivated soils re-emphasizes the need to employ erosion control measures.