Estimation of phenotypic divergence in a collection of <Emphasis Type="Italic">Capsicum</Emphasis> species for yield-related traits

Phenotypic divergence among the 24 accessions belonging to a collection of six species of Capsicum from different geoclimatic regions available in field gene bank of CIMAP, Lucknow, India, was quantified by multivariate analysis for 12 quantitative and qualitative traits. Based on their values, all 24 accessions were grouped into six clusters such that the genetic stocks within cluster had smaller D ² values among themselves than those belonging to different clusters. The accessions of Capsicum annuum were distributed in different clusters in morphotyping representing different species, suggesting that taxonomic characteristics are not always related to agronomic traits. No parallelism/association was found between geographical and phenotypic diversity. Accessions 15 and 23 (clusters V and VI, respectively) had distinct identity. The three characteristics that played the greatest role in differentiation were fruit diameter, number of fruits per plant, and leaf diameter, which can be utilized as conventional/morphological markers for the improvement of chilli yield and obtaining good segregants in chilli breeding programs.     

The Cytological Status of Plants Regenerated from Shoot-Meristem Culture of Pisum sativum L

The cytological status of plantlets regenerated from shoot apical meristems of Pisum sativum was investigated. Chromosome counts in root apices of in vitro regenerated plants showed a preponderance of diploid cells. Moreover, the karyotypes of root-tips from plants derived from culture and from normal plants were basically the same. Topics such as the treatment of chromosomal armlength data, simple statistical comparison of samples derived from normal and regenerated plants are discussed.     

Male-sterility in the grain amaranth (Amaranthus hypochondriacus ex-Nepal) variety Jumla

Summary Twenty naturally occurring male-sterile plants were recovered from a normal population of the grain amaranth, variety Jumla. The identification of the male-sterile plants is possible during anthesis and after flowering. The male-sterility in this variety is conditioned by a single recessive nuclear gene ms.This research was supported by Grant No. AMA-KE-4-83-22 (CRG GRANT) from the National Academy of Science, USA. Reprint requests to V.K. Gupta.     

Chromosomal Stability in the Backcross Progenies of Pentaploid Hybrids between Avena sativa L. and A. maroccana Gdgr.

In a backcrossing programme to transfer desirable characters from wild Avena maroccana Gdgr. to cultivated oats, A. sativa L., meiotically stable plants in BC₁F₃ and BC₂F₂ progenies were isolated. The recovery of stable genotypes with 2n = 6×= 42 chromosomes indicated that two backcrosses are enough for such a programme. The cytological observations in various backcross generations are presented and discussed.     

Integrated effect of transplanting date, cultivar and irrigation on yield, water saving and water productivity of rice (Oryza sativa L.) in Indian Punjab: Field and simulation study

Individual effect of different field scale management interventions for water saving in rice viz. changing date of transplanting, cultivar and irrigation schedule on yield, water saving and water productivity is well documented in the literature. However, little is known about their integrated effect. To study that, field experimentation and modeling approach was used. Field experiments were conducted for 2 years (2006 and 2007) at Punjab Agricultural University Farm, Ludhiana on a deep alluvial loamy sand Typic Ustipsamment soils developed under hyper-thermic regime. Treatments included three dates of transplanting (25 May, 10 June and 25 June), two cultivars (PR 118 inbred and RH 257 hybrid) and two irrigation schedules (2-days drainage period and at soil water suction of 16 kPa). The model used was CropSyst, which has already been calibrated for growth (periodic biomass and LAI) of rice and soil water content in two independent experiments. The main findings of the field and simulation studies conducted are compared to any individual, integrated management of transplanting date, cultivar and irrigation, sustained yield (6.3-7.5 t ha⁻¹) and saved substantial amount of water in rice. For example, with two management interventions, i.e. shifting of transplanting date to lower evaporative demand (from 5 May to 25 June) concomitant with growing of short duration hybrid variety (90 days from transplanting to harvest), the total real water saving (wet saving) through reduction in evapotranspiration (ET) was 140 mm, which was almost double than managing the single, i.e. 66 mm by shifting transplanting or 71 mm by growing short duration hybrid variety. Shifting the transplanting date saved water through reduction in soil water evaporation component while growing of short duration variety through reduction in both evaporation and transpiration components of water balance. Managing irrigation water schedule based on soil water suction of 16 kPa at 15-20 cm soil depth, compared to 2-day drainage, did not save water in real (wet saving), however, it resulted into apparent water saving (dry saving). The real crop water productivity (marketable yield/ET) was more by 17% in 25th June transplanted rice than 25th May, 23% in short duration variety than long and 2% in irrigation treatment of 16 kPa soil water suction than 2-days drainage. The corresponding values for the apparent crop water productivity (marketable yield/irrigation water applied) were 16, 20 and 50%, respectively. Pooled experimental data of 2 years showed that with managing irrigation scheduling based on soil water suction of 16 kPa at 15-20 cm soil depth, though 700 mm irrigation water was saved but the associated yield was reduced by 277 kg ha⁻¹.     

Effect of organic and inorganic sources of nutrients on soil microbial activity and soil organic carbon build-up under rice in west coast of India

The effect of medium-term (5 years) application of organic and inorganic sources of nutrients (as mineral or inorganic fertilizers) on soil organic carbon (SOC), SOC stock, carbon (C) build-up rate, microbial and enzyme activities in flooded rice soils was tested in west coast of India. Compared to the application of vermicompost, glyricidia (Glyricidia maculate) (fresh) and eupatorium (Chromolaena adenophorum) (fresh) and dhaincha (Sesbania rostrata) (fresh), the application of farmyard manure (FYM) and combined application of paddy straw (dry) and water hyacinth (PsWh) (fresh) improved the SOC content significantly (p < 0.05). The lowest (p < 0.05) SOC content (0.81%) was observed in untreated control. The highest (p < 0.05) SOC stock (23.7 Mg C ha^?1) was observed in FYM-treated plots followed by recommended dose of mineral fertilizer (RDF) (23.2 Mg C ha^?1) and it was lowest (16.5 Mg C ha^?1) in untreated control. Soil microbial biomass carbon (C_mb) (246 µg g^?1 soil) and C_mb/SOC (1.92%) were highest (p < 0.05) in FYM-treated plot. The highest (p < 0.05) value of metabolic quotient (qCO₂) was recorded under RDF (19.7 µg CO₂-C g^?1 C_mb h^?1) and untreated control (19.6 µg CO₂-C g^?1 C_mb h^?1). Application of organic and inorganic sources of nutrients impacted soil enzyme activities significantly (p < 0.05) with FYM causing highest dehydrogenase (20.5 µg TPF g^?1 day^?1), phosphatase (659 µg PNP g^?1 h^?1) and urease (0.29 µg urea g^?1 h^?1) activities. Application of organic source of nutrients especially FYM improved the microbial and enzyme activities in flooded and transplanted rice soils. Although the grain yield was higher with the application of RDF, but the use of FYM as an organic agricultural practice is more useful when efforts are intended to conserve more SOC and improved microbial activity.     

Metroglyph analysis of Indian and exotic varieties of maize

Summary Metroglyph and index score analysis was carried out with 15 Indian and 15 exotic varieties of maize currently being used in the breeding programme of the Coordinated Maize Improvement Project at the Indian Agricultural Research Institute. It was found that the Indian varieties under study fall into three morphological complexes which differed among themselves. The variability pattern of the second and third Indian complexes resembled that of Mexican and Colombian germ plasm. The variability pattern of the Caribbean germ plasm was different from the Indian complexes. Index score analysis also gave similar results. Previous breeding experiments also confirmed the findings that these varieties might have originated from a few Mexican or Colombian introductions.     

Stress distribution over a triangular tillage tool

To simplify the analysis of stress over a cultivator shovel moving at a certain depth, it was represented by an isosceles triangular plate of uniform thickness. To simulate the boundary conditions to which a cultivator shovel is subjected, the triangular plate was assumed as clamped along one of the edges while the other two edges were assumed as free. These assumptions made it possible to apply the theory of bending of laterally loaded plates for the computation of stresses set up in the tillage tool. This theory involves fundamental equations of elasticity, namely the equations of equilibrium, equations of continuity and surface conditions. The theoretically calculated values of stresses were fairly close to experimentally observed values.     

Heavy metal accumulation by three species of mosses in Shillong,North-Eastern India

Comparisons were made of the accumulation of cadmium, copper, manganese, lead, and zinc in Plagiothecium denticulatum, Bryum argenteum and Sphagnum sp. in Shillong, Meghalaya State, Northeastern India. Samples of P. denticulatum and B. argenteum were collected inside Shillong city (urban) and its immediately adjacent outskirts (suburban), while Sphagnum sp. was collected from a suburban site only. Lead and copper levels were higher in P. denticulatum, while Sphagnum sp. accumulated higher amounts of zinc, manganese, and cadmium. An urban-suburban gradient was evident for lead and zinc in P. denticulatum, and for cadmium in B. argenteum, while a reverse trend could be discerned for manganese in P. denticulatum. Besides vehicles and minor industries, quarry dust was likely to be an important source of manganese, copper, and zinc.