Relative effects of parents on some economic characters in sugarcane

Studies on the relative effects of parents on some economic characters in sugarcane have given indications of maternal influence in the progeny performance in certain crosses with regard to millable canes at harvest, height of stalks and brix per cent in juice, irrespective of the fact that pollen parent effect was positive or negative. As judged from a study of the progeny of the direct crosses and reciprocals among the varieties studied, particularly use of Co. 678 as a pistil parent in the breeding programme for improving the mean height of the progeny and Co. 527 as a pistil parent for increasing number of millable canes at harvest and brix per cent in juice is clearly indicated. These indications should also prove useful for application in adopting the polycross method of breeding as well.     

Flat fish eggs,larvae and their development

Studies on development of eight species of flat fishes (Psettodes erumei, Brachypleura novae-zeelandiae, Pseudorhombus arsius, Bothus myriaster, Synaptura albomaculata, S. commersoniana, Cynoglossus arel and C. monopus) were carried out with plankton collections and with laboratory reared larvae. The development stages of Cynoglossus arel and C. monopus from egg to metamorphosis are described.     

Breeding biology of Psettodes erumei (Bloch & Schn.) and Pseudorhombus arsius (Ham. Buch.) Pisces: Pleuronectiformes along Porto Novo coast (S. India)

Studies on the development of ova up to maturity clearly indicated that Psettodes erumei and Pseudorhombus arsius breed only once a year for 3 to 4 months in Porto Novo waters. Psettodes erumei spawns its eggs in two batches, while Pseudorhombus arsius spawns in a single batch. The spawning period of Psettodes erumei was from May to September, with the peak from May to August. Pseudorhombus arsius spawns during April to July, with the peak in April and May. Studies on the gonadosomatic indices confirm the above information. The size at first maturity of Psettodes erumei was 371–390 mm total length, and that of Pseudorhombus arsius was between 161 and 170 mm total length. Females always outnumbered males in both the species. Fecundity studies in both species showed direct correlations with total length and body weight.     

Soil protists: An untapped microbial resource of agriculture and environmental importance

Protists are essential components of soil biodiversity and ecosystem functioning. They play a vital role in the microbial food web as consumers of bacteria, fungi, and other small eukaryotes and are also involved in maintaining soil fertility and plant productivity. Protists also contribute to regulating and shaping the bacterial community in terrestrial ecosystems via specific prey spectra. They play a role in plant growth promotion and plant health improvement,mostly via nutrient cycling, grazing, and the activation of bacterial genes required for plant growth and phytopathogen suppression. Thus, protists may prove to be a useful inoculant as biofertilizer and biocontrol agent. They can also be applied as model organisms as bioindicators of soil health. Despite their usefulness and essentiality, they are often forgotten and under-researched components of the soil microbiome, as most of our research focuses on bacteria and fungi. In this review, we provide an overview of the role of protists in plant productivity and plant health management and in shifts in soil bacterial community composition, as well as their roles as bioindicator. We also discuss the perspectives of knowledge gaps and future prospects to further improve soil biology.More research in soil protistology will provide insights into sustainable agriculture and environmental health alongside the study of bacteria and fungi.     

Effects of stocking density and presence or absence of soil base on growth,weight variation,survival and body composition of pearlspot,Etroplus suratensis (Bloch) fingerlings

With the objective to develop an indoor tank seed rearing system for pearlspot (Etroplus suratensis), effects of three stocking densities in presence or absence of soil base were evaluated on growth, weight variation, survival and body composition in a 60‐day trial. The experiment had a 3 × 2 factorial design with three levels of stocking density (150, 300 and 450 fish m^?3) and two levels of soil base (with and without) in triplicates. Pearlspot fry (27.5 ± 0.5 mm/0.39 ± 0.02 g) were stocked in experimental tanks (Length×Breadth×Height: 0.65 × 0.50 × 0.48 m) and fed with a formulated diet containing 29.85% crude protein. Increasing the stocking density from 150 to 450 fish m^?3 significantly decreased the growth (average body weight and total length), daily weight gain, specific growth rate and survival (P < 0.001) and increased the feed conversion ratio (P < 0.01). Significantly lower growth and survival were observed in treatment having soil base compared with that of without soil base (P < 0.001). However, coefficients of variation at harvest weight and body composition of fingerlings were independent to stocking density and presence or absence of soil base (P > 0.05). A significant positive interaction effect of stocking density and presence or absence of soil base was observed on average body weight (P < 0.05) and survival (P < 0.001) of pearlspot fingerlings. This study suggests that stocking density of 150 fish m^?3 without soil base in tanks would be appropriate for raising pearlspot fingerlings in brackishwater indoor seed rearing system.     

Effects of arbuscular mycorrhizal fungus Rhizoglomus intraradices on active and passive pools of carbon in long-term soil fertility gradients of maize based cropping system

A potculture study was conducted in soils collected from long-term fertilizer experiment (LTFE) being kept up as far the past 40 years to determine whether arbuscular mycorrhizal fungus (AMF) Rhizoglomus intraradices colonization changes the active and passive pools of carbon in a maize (Zea mays) – finger millet (Eleusine crocana)- cowpea (Vigna sinensis) cropping sequence in the Experimental Farm of the Tamil Nadu Agricultural University, Coimbatore, India. Soil samples were processed, sterilized and maize plants were grown in various fertility gradients in the absence (M-) or presence (M+) of AMF (Rhizoglomus intraradices) inoculation. The data have clearly shown that M+ soils had consistently higher active pools such as water soluble carbon, hot water soluble carbon and biomass carbon (M- 189; M + 305 mg kg^?1), and passive pools such as soil organic carbon (M- 4.17; M + 4.31 mg g^?1) and total glomalin. Among the fertility gradients, 100% NPK + Farm Yard Manure (FYM) with or without mycorrhizal fungal inoculation registered higher values for both active and passive pools of C but the response was more pronounced in the presence AMF inoculation. Overall, the data suggest that mycorrhizal fungal inoculation assists in effective carbon sequestration in an intensive cereal-legume cropping system.Abbreviations: AMF: Arbuscular mycorrhizal fungi; DAS: Days After Sowing; LTFE: Long-Term Fertilizer Experiment; WSC: Water soluble organic carbon; HA: Humic acid; FA: Fulvic acid; HWSC: Hot water soluble carbon     

In vitro ectomycorrhizal formation of Pinus patula, P. pseudostrobus, P. oocarpa and P. elliotii grown in southern India

In vitro syntheses of ectomycorrhizas of Pinus patula, P. pseudostrobus, P. oocarpa and P. elliotii with Amanita muscaria, Laccaria fraterna, L. laccata, Pisolithus tinctorius, Rhizopogon luteolus, Scleroderma citrinum and Thelephora terrestris were attempted. Most of the fungi initiated mycorrhizal formation within 2 weeks after inoculation. Laccaria fraterna and S. citrinum formed mycorrhizas after 6 weeks of inoculation. Amanita muscaria failed to form mycorrhizas during the 12 week period of observation. The degree of colonization of different mycorrhizal fungi varied with different species of Pinus.     

Prevalence of nematode parasite,Contracaecum, in Nile tilapia,African catfish and Barbus species in Lake Hawassa,Ethiopia

A cross‐sectional study was conducted from November 2017 to March 2018 at Lake Hawassa to determine the prevalence of larval Contracaecum infestation in Nile tilapia, (Oreochromis niloticus), African Catfish (Clarias gariepinus) and Barbus species (Barbus intermedius). Fifty‐two point six per cent (52.6%) previous prevalence and 5% precision were used to estimate the sample size. Accordingly, a total of 383 randomly sampled fish species comprising of 163 (42.6%) C. gariepinus, 159 (41.5%) O. niloticus and 61(15.9%) B. intermedius were examined. The length and weight of each sampled fish were recorded. All the sampled fish were examined for the evidence of Contracaecum parasites in Hawassa University Veterinary Parasitology and Pathology Laboratory. Chi‐square values and comparison of proportions were used to analyse the data. The overall prevalence of Contracaecum parasites of fish population was 31.6%. The distribution of parasite was significantly affected by fish species (p = .000), sexes (p = .018), length (p = .003) and weight classes of fish (p = .026). As a hygienic problem and gutting activity conducted at the sides of the Lake Hawassa and distribution of discarded fish wastes for surrounding piscivorous birds by butchers and other people, the life cycle of Contracaecum parasite was perpetuated. Thus, the parasite is of zoonotic significance. Therefore, awareness creation activities for societies and control of fish parasites should be conducted in the study area.     

Limited contribution of water availability in genotype-by-environment interaction in sugarcane yield and yield components

Water deficit is an important abiotic stress factor limiting sugarcane production. Understanding the effect of water deficit on cane yield, yield components and genotype × environment (G × E) interaction can aid in selecting genotypes that are adapted to water deficit conditions. In this study, response of cane yield and yield components of 10 sugarcane genotypes grown under 3 irrigation treatments—fully irrigated, semi-irrigated and rainfed—was examined across 3 locations and 3 crop-years within each location. Cane yield reduced by 32% and 9% in the rainfed and semi-irrigated treatments, respectively, compared to the fully irrigated treatment. Genotypic variation was highly significant for cane yield and yield components in all three irrigation regimes. Cane yield in the rainfed treatment showed significant genetic correlation with stalk diameter (r_g = 0.68), leaf number (r_g = 0.64), node number (r_g = 0.67) and stalk number (r_g = 0.68). Genotype × irrigation variance was negligible compared to genotype, genotype × location and genotype × crop-year variances. Commercial genotypes had higher yield in most environments except in low-yield potential environments, which caused a significant genotype × location × irrigation effect, suggesting opportunities for improving sugarcane productivity in these environments.     

Effect of six decades of selective breeding on soybean protein composition and quality: a biochemical and molecular analysis

To evaluate the extent of the genetic change and its effects on the seed protein composition of soybean cultivars released during the past 60 years, representative ancestral cultivars and those derived from selective breeding were grown in a side-by-side comparison. Total seed protein content, determined by combustion analysis of nitrogen, revealed a decline in the protein content after decades of selection and breeding. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis comparison of protein profiles of the soybean cultivars indicated that relative expression of most of the seed storage proteins had not varied substantially from the ancestral lines to the present commercial cultivars. There was noticeably less beta-subunit of beta-conglycinin, a protein devoid of sulfur amino acids, in the modern cultivars represented by Mustang, Pioneer 93B09, and Asgrow 3602. Comparison of the amino acid profiles of soybean seed, a benchmark of the protein's nutritional quality, revealed that the ancestral progenitor, G. soja, was significantly higher in cysteine, glutamic acid, histidine, and arginine than either the ancestral or the modern cultivars. Selective breeding over the past 60 years minimally affected the overall amino acid composition. The degree of divergence in the DNA sequence of the genes encoding glycinin and beta-conglycinin in the ancestral and modern cultivars was investigated using Southern hybridization and the polymerase chain reaction. Even though some restriction fragment polymorphisms could be detected, overall, the banding patterns were remarkably similar among the ancestral cultivars and those derived from them, suggesting a high degree of conservation of seed-storage protein genes. The results of our study suggest that selection and breeding for yield during the past 60 years had no major influence on the protein composition, ostensibly because of limited genetic diversity among the parental lines.