Use of mixed feeding schedules in fish culture: performance of common carp, Cyprinus carpio L., on plant and animal protein based diets

A 90-day growth trial was conducted with common carp, Cyprinus carpio L., to test the suitability of mixed feeding using a plant-based low-protein diet (16% -diet A), and two fish-meal-based diets of 26% protein (diet B) and 31% protein (diet C). Three mixed feeding schedules were tested: 1A/2B, 2A/2B and 2A/2C; numerals refer to number of days each diet (A, B or C) was offered continuously. Fish fed diets A, B or C continuously served as controls. Fish grown on diet A grew the least, while there was no significant difference between those fed on diets B or C. Of the three mixed schedules, 2A/2C produced the highest growth, which was better than that on control diets B or C. Specific growth rate (%) and food conversion ratio and protein retention were found to be good for all mixed feeding schedules. The plant protein diet resulted in poor-quality flesh as indicated by carcass composition. The study supports the view that fish can be fed alternately with animal- and plant-protein-based diets of varied protein levels. This practice would help to reduce protein input, and would contribute to the efficient utilization of low-quality, plant-protein-based diets.     

Fingerprinting in cucumber and melon (<Emphasis Type="Italic">Cucumis</Emphasis> spp.) Genotypes using morphological and ISSR markers

In the present investigation, 13 Cucumis genotypes from different geographical areas of India were screened for genetic diversity using 19 morphological traits and 15 ISSR primers. The analysis of morphological traits grouped the accessions into six clusters. Cluster V contained the maximum number of genotypes namely Kanivellari, Long Green, Andaman Local, Perundurai Local, and Sempatti Local. Clusters I and VI contained the minimum number of genotypes. Among all the characters, the highest mean value was observed in fruit length (23.38) and the lowest mean value was observed in stripes on the blossom end (1.31). The 15 ISSR primers generated 109 polymorphic alleles. The average number of ISSR alleles generated was 8.3 per primer and the level of polymorphism was 87.20%. The ISSR primer UBC 825 was highly informative with a PIC value of 0.8934. The 13 genotypes were grouped into six clusters based on ISSR markers. Cluster III contained the maximum number of genotypes, namely Kanivellari, Sankagiri Local, Perundurai Local, Long Melon, and Sempatti Local, while Clusters I, II, IV, and V (Karur Local, Andaman Local, Edapaddi Local, and N 78, respectively) contained the minimum number of genotypes. The ISSR profile generated genotypes specific allele namely, UBC 812_700bp and UBC 812_1000bp for Cluster VI which contained Cucumis genotypes collected from the northern part of India. Similarly, UBC 808 produced specific allele UBC 808_650bp formed in Cluster III which contained genotypes collected from Tamil Nadu and Kerala.     

Genome-Wide Analysis of von Willebrand Factor A Gene Family in Rice for Its Role in Imparting Biotic Stress Resistance with Emphasis on Rice Blast Disease

von Willebrand factor A (vWA) genes are well characterized in humans except for few BONZAI genes, but the vWA genes are least explored in plants. Considering the novelty and vital role of vWA genes, this study aimed at characterization of vWA superfamily in rice. Rice genome was found to have 40 vWA genes distributed across all the 12 chromosomes, and 20 of the 40 vWA genes were unique while the remaining shared large fragment similarities with each other, indicating gene duplication. In addition to vWA domain, vWA proteins possess other different motifs or domains, such as ubiquitin interacting motif in protein degradation pathway, and RING finger in protein-protein interaction. Expression analysis of vWA genes in available expression data suggested that they probably function in biotic and abiotic stress responses including hormonal response and signaling. The frequency of transposon elements in the entire 3K rice germplasm was negligible except for 9 vWA genes, indicating the importance of these genes in rice. Structural and functional diversities showed that the vWA genes in a blast-resistant rice variety Tetep had huge variations compared to blast-susceptible rice varieties HP2216 and Nipponbare. qRT-PCR analysis of vWA genes in Magnaporthe oryzae infected rice tissues indicated OsvWA9, OsvWA36, OsvWA37 and OsvWA18 as the optimal candidate genes for disease resistance. This is the first attempt to characterize vWA gene family in plant species.     

Inland saline aquaculture increased carbon accumulation rate and stability in pond sediments under semi-arid climate

Purpose

Similar to fresh- and brackish water aquaculture ponds, commercial shrimp farming in degraded saline areas holds the potential to bury carbon (C) in the sediments. However, studies on the mechanisms of sediment C dynamics and C-flux in response to inland saline aquaculture management practices are still scarce. Therefore, the objectives of the present study are to quantify the C burial rate in inland saline aquaculture ponds and assess the impact of inland saline aquaculture on sensitive C fractions in the bottom sediment of the ponds.

Materials and methods

The sediment samples (n?=?12 from each pond) were collected from six shrimp farming ponds (1000 m² area of each pond) of different ages. The sediment depth, sediment accumulation rate and the levels of total carbon (TC), total organic carbon (TOC) and sediment oxidizable organic carbon (SOC) and its different fractions were determined using standard procedures. The data were analysed by one-way analysis of variance (ANOVA), followed by the Duncan's multiple range test for comparing the means, and the Pearson correlation test was used to assess the relationship between the different pond sediment parameters and SOC content.

Results and discussion

The results revealed that the annual C accumulation rates varied from 902 to 1346 kg C ha^?1 year^?1 in 7-year-old earthen ponds (EPs) and bottom cemented ponds (BCPs), respectively. The sediment C fractions, including TC, TOC, SOC and its fractions (very labile, VLc; labile, Lc; less labile, LLc), and non-labile carbon (NLc)) were progressively increased over the pond age. The inland saline aquaculture practices over the years increased both active (AC) and passive carbon (PC) pools in the pond sediments, helped in the restoration and improvement of sediment quality and enhanced C sequestration potential of the sediments. Furthermore, a significant increase in the level of particulate organic carbon (POC) in BCPs justified that the non-ploughing practices at BCPs facilitated the formation of macro- and micro-aggregates, thereby increasing the C retention and stability of the pond sediments.

Conclusion

This study suggested that the shrimp farming ponds in semi-arid saline soils represented considerable C burial hotspots, enhanced the stable passive C pools and improved the sediment quality.

     

Plant genetic resources of Nepal: A guide for plant breeders of agricultural, horticultural and forestry crops

Summary Nepal is rich in indigenous wild and landrace plant genetic resources for agronomic, horticultural, forestry, or medicinal uses, but much of this germplasm remains uncollected and awaits economic development. We list 485 entries (species, or genera for ornamental plants) in 14 categories, and compare these to existing germplasm collections in Nepal and the United States to highlight collection and conservation needs. To help plant plant collecting, we outline the key botanical and logistical data and legal framework for planning field work in Nepal.     

Mutagenic response of rhodes grass (Chloris gayana Kunth.) to gamma rays. II. Studies on second (M2) generation parameters

Summary The effect of gamma rays on parameters such as chlorophyll mutation frequency and spectrum, mutagenic effectiveness and efficiency and viable mutation frequency and spectrum were studied in M₂ generation of Rhodes grass employing nine doses of gamma rays. The chlorophyll mutation frequency increased in a linear fashion at low and medium doses and was erratic at higher doses. The chlorophyll mutant spectrum ineluded albina, xantha, chlorina, viridis, tigrina, striata, albo-xantha and albo-viridis. The frequency of these mutants varied with treatments. A dose rate of 60 krad was found to be effective as well as efficient both on M₁ and M₂ plant basis in inducing chlorophyll mutations. The highest frequency of viable mutations was found in 50 krad treatment. Viable mutants found were: nodal variant, peduncle variant, lax ears, coxcomb ears, earhead proliferation, level of fingers, incurved fingers, gappy ears, apical sterility, partial sterility and high sterility.     

Exploitation of wild annual Cicer species for widening the gene pool of chickpea cultivars

Introgression of unadapted genes from the wild Cicer species could contribute to the widening of genetic base of important traits such as yield, yield attributes and resistance to major biotic and abiotic stresses. An attempt was made successfully to intercross two wild annual Cicer species with three cultivated chickpea cultivars. Four interspecific cross‐combinations were made, and their true hybridity was ascertained through morphological and molecular markers. These cross‐combinations were also studied for some important quantitative traits under real field conditions. The range, mean and coefficient of variation of agro‐morphological traits were assessed in the parental lines, their F₁ and F₂ generations to determine the extent of variability generated in cultivated chickpea varieties. A high level of heterosis was recorded for number of pods/plant and seed yield/plant in F₁ generation. Three cross‐combinations of ‘Pusa 1103’ × ILWC 46, ‘Pusa 256’ × ILWC 46 and ‘Pusa 256’ × ILWC 239 exhibited substantially higher variability for important yield‐related traits. The present research findings indicate that these wild annual Cicer species can be easily exploited to broaden the genetic base of cultivated gene pool for improving seed yield as well as adaptation.     

Dynamics of fine and coarse roots and nitrogen mineralization in a humid subtropical forest ecosystem of northeast India

The present study was carried out to understand whether fine root growth and N mineralization are synchronized in such a manner that helps to conserve N in the humid subtropical forest ecosystem, and to assess whether or not these processes are influenced by human disturbance. The study was conducted in two pairs of undisturbed and disturbed stands of subtropical humid forest in the Jaintia hill district of Meghalaya, northeast India. The amount of fine root (540–754 g m^–2) and coarse root (307–387 g m^–2) mass in the protected stands was higher than those recorded (fine root 422–466 g m^–2, coarse root 247–305 g m^–2) in the unprotected stands. The total annual root production was also higher in the protected stands (1,102–1,242 g m^–2) than the unprotected stands (890–940 g m^–2). The mean concentration of NH₄⁺–N and NO₃^––N was higher in the protected stands than in the unprotected stands. The inorganic-N (NH₄⁺–N and NO₃^––N) concentration was markedly high during the dry period and low during the wet period in all the stands. Inorganic-N concentration, nitrification and N mineralization rates were significantly (P<0.01) higher in the surface (0–10 cm) than the subsurface (10–20 cm) layer. The low and high N mineralization rates observed during the dry and wet periods, respectively, coincided with the lean and peak periods of fine root mass. Disturbance in the forests caused a reduction in fine root mass as well as in N mineralization.     

Isoflavone,glyphosate, and aminomethylphosphonic acid levels in seeds of glyphosate-treated,glyphosate-resistant soybean

The estrogenic isoflavones of soybeans and their glycosides are products of the shikimate pathway, the target pathway of glyphosate. This study tested the hypothesis that nonphytotoxic levels of glyphosate and other herbicides known to affect phenolic compound biosynthesis might influence levels of these nutraceutical compounds in glyphosate-resistant soybeans. The effects of glyphosate and other herbicides were determined on estrogenic isoflavones and shikimate in glyphosate-resistant soybeans from identical experiments conducted on different cultivars in Mississippi and Missouri. Four commonly used herbicide treatments were compared to a hand-weeded control. The herbicide treatments were (1) glyphosate at 1260 g/ha at 3 weeks after planting (WAP), followed by glyphosate at 840 g/ha at 6 WAP; (2) sulfentrazone at 168 g/ha plus chlorimuron at 34 g/ha applied preemergence (PRE), followed by glyphosate at 1260 g/ha at 6 WAP; (3) sulfentrazone at 168 g/ha plus chlorimuron at 34 g/ha applied PRE, followed by glyphosate at 1260 g/ha at full bloom; and (4) sulfentrazone at 168 g/ha plus chlorimuron at 34 g/ha applied PRE, followed by acifluorfen at 280 g/ha plus bentazon at 560 g/ha plus clethodim at 140 g/ha at 6 WAP. Soybeans were harvested at maturity, and seeds were analyzed for daidzein, daidzin, genistein, genistin, glycitin, glycitein, shikimate, glyphosate, and the glyphosate degradation product, aminomethylphosphonic acid (AMPA). There were no remarkable effects of any treatment on the contents of any of the biosynthetic compounds in soybean seed from either test site, indicating that early and later season applications of glyphosate have no effects on phytoestrogen levels in glyphosate-resistant soybeans. Glyphosate and AMPA residues were higher in seeds from treatment 3 than from the other two treatments in which glyphosate was used earlier. Intermediate levels were found in treatments 1 and 2. Low levels of glyphosate and AMPA were found in treatment 4 and a hand-weeded control, apparently due to herbicide drift.