Mangrove horseshoe crab (Carcinoscorpius rotundicauda Latreille, 1802) populations reveal genetic break in Strait of Malacca,with connectivity along southern coasts of Peninsular Malaysia

1. The mangrove horseshoe crab, Carcinoscorpius rotundicauda, has divergent populations between the east and west coasts of Peninsular Malaysia, with the southern coast acting as a land barrier. The actual position of such a genetic break along Peninsular Malaysia as well as the connectivity status of the southernmost C. rotundicauda populations with east and west coast populations remain unexplored, however.
2. The aim was to investigate the genetic diversity and structure of C. rotundicauda populations from the west (Kuala Sepetang in State Perak), east (Balok in State Pahang), and southern (Pendas in State Johor) coasts of Peninsular Malaysia. Haemolymph samples from adult C. rotundicauda specimens (n = 152) and eggs from their freshly deposited nests (n = 190) were collected monthly (from January 2016 to January 2017) for the sequencing of mitochondrial cytochrome c oxidase subunit I (COI).
3. Gene isolates of C. rotundicauda from the present study were compared with National Center for Biotechnology Information (NCBI) GenBank sequences to cover most of the range of the species in Asia. A neighbour-joining tree strongly supported two clades, separating the west-coast populations from the south- and east-coast populations, with further substructure patterns.
4. Both haplotype network and barrier analyses revealed a genetic break within the Strait of Malacca instead of the southern tip of Peninsular Malaysia. The southernmost samples from the Strait of Johor formed a haplotypic diverse gene pool that appeared only as a subclade of the eastern populations. In a detailed haplotype network of 347 individuals, individuals with similar COI sequences indicate connectivity between C. rotundicauda on the east and C. rotundicauda on south and south west of Peninsular Malaysia.
5. Overall, the genetic break between C. rotundicauda populations is better explained by the convergent ocean currents and available mangrove habitats on the west coast (i.e. Strait of Malacca), rather than the point of the Malay Peninsula acting as a land barrier alone.

     

Role of live microbial feed supplements with reference to anaerobic fungi in ruminant productivity:A review

To keep the concept of a safe food supply to the consumers, animal feed industries world over are showing an increasing interest in the direct-fed microbials (DFM) for improved animal performance in te...     

Influence of field re-ponding pattern and plant spacing on rice root–shoot characteristics,yield, and water productivity of two modern cultivars under SRI management in Indian Mollisols

A 2-year field experiment was conducted during the wet seasons (July–October) of 2008 and 2009 on a Typic Hapludoll Mollisol in Indo-Gangetic Plains Region (IGPR) to: (i) investigate the effects of field water re-ponding intervals and plant spacing on the growth, yield, and water productivity (WP) of two rice cultivars under system of rice intensification (SRI) management, and (ii) assess comparative performance of SRI versus ‘best management practices’(BMP) of rice cultivation. This experiment was designed with 14 treatments, 12 under SRI, and 2 BMP (controls). SRI treatments comprised of 3 irrigation regimes viz, irrigation at 1, 3, and 5 day(s) after disappearance of ponded water (DADPW), 2 plant spacings (20 × 20, 25 × 25 cm), and 2 rice cultivars (Pant Dhan 4 and Hybrid 6444). Two BMP (control) treatments comprised of standard cultivation recommendations for flooding and spacing. The experiment was laid-out in a factorial randomized complete block design with three replications. Statistical analysis of data revealed significant variations in root–shoot characteristics and rice yield under SRI between years, reflecting different rainfall patterns. During 2009, a low rainfall year, the panicle numbers m^?2, dry root weight m^?2, root volume m^?2, filled spikelet number panicle^?1, and filled spikelet weight panicle^?1 were significantly higher, which resulted in a rice grain yield enhancement by 5.1 % over 2008, when there was unusually heavy rainfall. Climate × irrigation regime interaction revealed a non-significant influence of irrigation regimes on growth and yield during 2008, whereas in 2009, irrigation at 1 DADPW and 3 DADPW increased grain yield by 12.8 and 8 %, respectively over 5 DADPW. Better root–zone soil moisture regimes, balancing water, and oxygen availability were responsible for higher yields under irrigation at 1 and 3 DADPW. In 2008, soil moisture content (SMC) in 0–15 cm layer was 91, 86, and 82 % of field capacity (FC) at panicle initiation, and 88, 80, and 77 % at panicle emergence stage when irrigation was at 1, 3, and 5 DADPW, respectively; the lower layers (15–30, 30–45 cm) retained their SMC between 87 and 94 % of FC at both stages. During 2009, SMC in all the three layers at both stages was more than 85 % of FC when irrigating at 1 DADPW, and a little more than 70 % for the 0–15 cm layer and >80 % for the other two layers when irrigation was done at 3 DADPW. SMC dropped to below 60 % of FC in the 0–15 cm layer and remained between 67 and 77 % of FC in the other two layers, with lower yield resulting when irrigations were applied at 5 DADPW. However, WP was the highest with irrigation at 5 DADPW (38.5 kg ha cm^?1). Wider plant spacing (25 × 25 cm) resulted in generally and significantly higher grain yield and WP. On an average, SRI (6.1 t ha^?1) resulted in yield advantage of 0.9 t ha^?1 over BMP (5.2 t ha^?1). Overall, it is inferred that in SRI, wider planting (25 × 25 cm) with field re-ponding at 3 DADPW if there is adequate water availability and at 5 DADPW under limited water supply conditions, may lead to higher rice yields and WP in sub-humid tarai Mollisols of IGPR and comparable agro-climatic conditions in Indian sub-continent.     

Bed planted rice–wheat rotation at differential soil moisture regimes on soil hydro-physical properties, root growth, nitrogen uptake, and system productivity

Along with most widely practiced resources conserving technology zero-tillage wheat after rice, adoption of permanent beds for rice–wheat rotation is also gaining popularity. Since relatively a new approach particularly for dry-seeded rice and permanent beds for wheat, very little information is known about permanent beds on soil properties, nutrient (N) use efficiency, and system productivity. A field experiment was carried out in a Typic Haplustept soil of New Delhi, India to study the effect of permanent beds on soil hydro-physical properties, root growth, nitrogen uptake, and system productivity of irrigated rice–wheat rotation. Results revealed that direct-seeded rice followed by wheat on permanent beds irrigated at different soil water tensions (field capacity, 20 and 40 kPa) reflected a significant variation in soil hydro-physical properties, reduced total nitrogen uptake, contribution by different plant parts, and N use efficiency compared to wheat after flooded transplanted rice system. Rice root weight density at flowering was also significantly low at 0–15 cm depth but higher at 15–60 cm depth in dry-seeded rice on beds. System productivity of rice–wheat rotation was 25–33% lower in permanent beds compared to flooded transplanted system. For wider acceptability of permanent beds as a promising resource conserving technology, system productivity needs to be improved.     

Objective assessment of sperm motion characteristics of Malpura ram lambs raised under intensive management system in semiarid tropical environment

A study was conducted to evaluate the semen production and sperm motion characteristics of ram lambs by computer-aided semen analysis technique. Eight Malpura rams were raised under intensive management system and were trained for semen collection at a weekly interval from the age of 6 months. Rams were scheduled for semen collection at a weekly interval up to 1 year of age to assess their potential for semen production and objective evaluation of semen quality. The average age of ram lambs at the time of first ejaculation was 219 days ranging from 186 to 245 days. The age of ram lambs significantly (p < 0.05) influenced sperm concentration, sperm velocities, and beat frequency of spermatozoa, which were higher in 9–12-month-old compared to 6–9-month-old ram lambs. However, the effect of age was not significant on semen volume, percent motility, percent rapid, medium or slow motile spermatozoa, percent linearity, percent straightness, amplitude of lateral head displacement, percent elongation, and area of sperm head. The body weight of ram lambs was significantly (p < 0.01) and positively correlated (r = 0.46) with age. The results indicate that Malpura ram lambs of 9–12 months of age raised under the intensive management system in a semiarid tropical environment can produce good quality of semen.     

Growth and development of fall- and spring-planted populations of Conyza canadensis and C. bonariensis

The growth and phenological development of spring- and fall-planted Conyza canadensis and C. bonariensis were studied in Fresno, CA, USA. A glyphosate-resistant (GR) and a glyphosate-susceptible (GS) population of each species were used. Time taken by each plant to reach the rosette, bolting, appearance of first bud, appearance of first open flower, and initial seed set were converted to growing degree days (GDDs). The fall- and spring-planted C. canadensis required similar GDDs to complete their life cycles but the GR type required fewer GDDs than the GS type. In C. bonariensis, the GDDs required to complete its life cycle differed between the fall- and spring-plantings but not between the GR and GS types. The total aboveground biomass of both fall- and spring-planted Conyzas at initial seed set was similar but the spring-planted GS C. canadensis produced more biomass than the GR type, whereas the fall-planted GS C. bonariensis produced more biomass than the GR type. Plant development based on GDD models can have global implications and help in planning for timely applications of post-emergence herbicides.     

Limitations of PCR‐based molecular markers to identify male‐sterile and maintainer plants from Indian onion (Allium cepa L.) populations

The main aim of this study was to validate PCR markers for determining cytoplasm and genotypes at the Ms locus in short‐day onion. Three cytoplasmic (OSN, MKFR and accD) and four nuclear (OPT, jnurf13, AcSKP1 and AcPMS1) markers were employed. Sel. 121‐1 had 100% S cytoplasm, whereas Sel. 121‐2, ‘Pusa Red’ and ‘Pusa Madhavi’ had 88%, 33% and 17% S cytoplasm, respectively. ‘Early Grano’ and ‘Pusa Riddhi’ did not possess S cytoplasm. Observations in 33 commercial varieties revealed two with sterile (S) cytoplasm. Nuclear markers were not found in linkage disequilibrium with the Ms locus, and the constitution of Ms alleles by OPT was different from other three markers, which were in conformity with each other. The other three markers predicted that most of the plants should be homozygous recessive. Anther colour also did not confirm the sterility status. It can be concluded that accD may be used for cytoplasm determination based on the ease of its use. For the Ms locus tagging, more markers are needed to be evaluated to isolate maintainer lines from open‐pollinated populations.     

AM fungi lead to fertilizer phosphorus economy and enhanced system productivity and profitability in okra (Abelmoschus esculentus L.)–pea (Pisum sativum L.) cropping system in Himalayan acid Alfisol

The present investigation was carried out at CSK Himachal Pradesh Agricultural University, Palampur, Himachal Pradesh, India, during 2009–2011 to economize inorganic phosphorus (P) and enhance profitability of okra (Abelmoschus esculentus)–pea (Pisum sativum) cropping system through arbuscular mycorrhizal fungi (AMF). A field experiment was replicated thrice in a randomized block design comprising 14 treatments involving AMF (Glomus mosseae) at varying inorganic P (50%, 75%, and 100% of recommended soil test-based P dose) and irrigation regimes (40% and 80% available water capacity] in a Himalayan acid Alfisol. In okra, AMF inoculation at varying P and irrigation regimes registered higher P response ratio (PRR), net returns (10–18%), and benefit:cost (B:C) ratio (17–49%) compared to “generalized recommended P dose (GRD)” and their non-AMF counterparts. Similarly in pea, AMF inoculation at varying P and irrigation regimes again registered higher PRR, net returns (14–23%), and B:C ratio (10–58%) compared to GRD and non-AMF counterparts. Higher system productivity (7–16%) and profitability in terms of net returns (9–23%) and B:C ratio (10–54%) were also registered in AMF-imbedded treatments compared to non-AMF counterparts. Further, “AMF + 75% soil test-based P dose” at either of these irrigation regimes registered statistically similar okra–pea system productivity and profitability as that obtained under “100% soil test-based P dose” at either of two irrigation regimes, thus indicating an economy of soil test-based applied P dose by about 25%. Overall, the current study suggests that practice of AMF inoculation has great potential in enhancing system productivity and profitability besides cutting down about 25% inorganic P requirement in okra–pea production system in the Himalayan acid Alfisol.     

Heat shock protein 70, oxidative stress, and antioxidant status in periparturient crossbred cows supplemented with α-tocopherol acetate

The study was conducted to investigating the effect of α-tocopherol acetate on heat shock protein 70 (Hsp70), oxidative stress, and antioxidant status during periparturient period in medium body condition score crossbred cows. Twenty crossbred Karan Fries cows with confirmed pregnancy were selected 2 months before expected date of calving. The cows were randomly distributed in to two groups: 10 cows were kept as control and 10 were supplemented with α-tocopherol acetate during dry period for 2 months. Blood samples were collected at ?20, ?10, ?5, 0, 5, 10, and 20 days in relation to the expected date of calving. Superoxide dismutase, catalase, and total immunoglobulin were significantly higher (P?<?0.01) in treatment as compared to control cows. Heat shock protein 70 and thiobarbituric acid reactive substance levels were significantly lower (P?<?0.01) in the treatment cows than their counterpart. Treatment with α-tocopherol acetate during dry period resulted in reduced oxidative stress, heat shock protein Hsp70 levels, improved antioxidant, and improved immunity status indicating beneficial effect of α-tocopherol acetate treatment.