Importance of the Shatsky Rise Area in the Kuroshio Extension as an offshore nursery ground for Japanese anchovy (Engraulis japonicus) and sardine (Sardinops melanostictus)

Recent findings suggest that recruitment of Japanese anchovy (Engraulis japonicus) and sardine (Sardinops melanostictus) depends on survival during not only the first feeding larval stage in the Japanese coastal waters and the Kuroshio front but also during the post‐larval and juvenile stages in the Kuroshio Extension. Spatial distributions of juvenile anchovy and sardine around the Shatsky Rise area in the Kuroshio Extension region and the Kuroshio–Oyashio transition region are described, based on a field survey in the late spring using a newly developed mid‐water trawl for sampling juveniles. All stages of anchovy from post‐larvae to juveniles were obtained in the northern Shatsky Rise area. The Kuroshio Extension bifurcates west of the Shatsky Rise area and eddies are generated, leading to higher chlorophyll concentrations than in the surrounding regions in April and May. When Japanese anchovy and sardine spawn near the Kuroshio front or the coastal waters south‐east of Japan, their larvae are transported by the Kuroshio Extension and are retained in the Shatsky Rise area, which forms an important offshore nursery ground, especially during periods of high stock abundance.     

Embryonic development of Ganga river prawn Macrobrachium gangeticum (Bate)

Macrobrachium gangeticum (Bate) are commercially valuable prawns that are broadly distributed in the Ganga river that flows from northern to eastern India. We studied embryonic development from cleavage (blastomeres), segmentation, formation of optic vesicle, eye pigment development to larva formation, as these data are largely unknown in this species. We conducted this study using mature M. gangeticum broodstock placed in freshwater tanks. Just after spawning, females were kept in separate aerated tanks, where fecundity was estimated from the total number of eggs. Thereafter, egg samples from berried females were used to study their embryonic stages. The correlation coefficient between size and prawn weight, egg weight, egg number, body weight and egg mass of different sizes of prawns was analysed. Our results show that an increase in prawn size led to an increase in egg weight and egg number while decreases in body weight:egg mass ratio was noticed. Further results indicate that an increase in prawn weight had a positive impact on egg weight and egg number. The embryo development stages were used in this study as a tool to evaluate the development process of the prawn in a hatchery environment.     

Identification of informative SSR markers capable of distinguishing hybrid rice parental lines and their utilization in seed purity assessment

With the objective of identifying SSR markers that can distinguish parental lines of rice hybrids, we characterized 10 each of cytoplasmic male sterile (CMS) and restorer (R) lines along with 10 popular Indian rice varieties using a set of 48 hyperpolymorphic SSRs distributed uniformly across the rice genome. All the SSR markers were polymorphic, amplifying a total of 163 alleles, with an average of 3.36 ± 1.3 allelic variants per locus. Twenty-seven SSR markers showed amplification of an allele, which was very specific and unique to a particular parental line and not amplified in any other rice genotype tested. Through multiplex PCR, SSR marker combinations that were unique to a particular parental line or hybrid were also identified. With a set of 10 SSR markers, all the public bred Indian rice hybrids along with their parental lines could be clearly distinguished. To utilize these SSR markers effectively for detection of impurities in parental lines, a two dimensional bulked DNA sampling strategy involving a 20 × 20 grow-out matrix has been designed and used for detection of contaminants in a seed-lot of the popular CMS line IR58025A. We have also designed a multiplex PCR strategy involving single tube analysis using 2–3 markers for hybrid seed purity assessments and demonstrate its superiority over single marker analysis in accurate detection of impurities in hybrids. Implications of parental and hybrid specific SSR markers and strategies to utilize the informative SSR markers for detection of contaminants in a cost effective manner are discussed.     

Intercropping ginger and turmeric with poplar (Populus deltoides ‘G-3’ Marsh.)

Performance of two rhizomatous crops i.e. ginger (Zingiber officinale Rosc.) and turmeric (Curcuma longa L.) was investigated under rainfed conditions in pure stands and as intercrops with 5-year-old poplars planted at three spacings viz., 5×5 m, 5×4 m and 5×3 m. The average illumination below the canopies was 53, 46 and 38% of incident radiation, respectively. Both crops performed better as intercrops than as pure stands. Survival was inversely correlated to light intensity. Plant height, tillers per plant and leaves per plant in ginger and leaf length and leaf breadth besides plant height in turmeric were significantly enhanced when intercropped. The rhizome length, rhizome breadth, yield per plant and yield per ha in ginger exceeded under poplars but showed a drastic reduction under the closest poplar spacing. In turmeric, the trend for the first two characters was the same, whereas yield per plant as well as yeild per ha were slightly greater in the open than under 5×3 m spacing. Dry matter content varied significantly with spacing. For quality parameters, only oil content in ginger and oleoresin in turmeric showed significant differences. The cultivation of turmeric proved more remunerative than ginger.Among the poplar spacings, 5×4 m for ginger and 5×5 m for turmeric were delineated as the best spacings.     

Biomass production and root distribution of Gmelina arborea under an agrisilviculture system in subhumid tropics of Central India

A study of an agrisilviculture system comprising Gmelina arborea and soybean (Glycine max) was conducted in the subhumid region of Central India. Above- and below-ground biomass production and distribution of coarse and fine roots were studied in 4-year-old G. arborea, planted at a spacing of 2 × 2 m, 2 × 3 m, 2 × 4 m and 2 × 5 m. The total biomass varied from 10.89 Mg ha^–1 to 3.65 Mg ha^–1 depending on the tree density. Among the different tree components, stemwood contributed maximum biomass (54.3–79.4%), followed by branches and leaves. Root distribution pattern showed that most of the coarse roots were distributed in the top 40 cm of soil, whereas fine roots were concentrated in the top 20 cm. Coarse root biomass decreased with an increase in spacing. The spread of roots was asymmetrical in trees planted at 2 × 2 m and 2 × 3 m spacings, while it was symmetrical in trees planted at wide spacings. No significant difference was observed in the fine root biomass in different stands. The root:shoot ratio increased with an increase in spacing. Crop (soybean) growth and productivity varied significantly and it increased with a decrease in tree density. Soybean yield varied between 1.5 Mg ha^–1 to 2.1 Mg ha^–1. The role of root architecture of G. arborea trees on productivity of crops under agri-silviculture system is discussed.     

Dysoxylum binectariferum Hook.f (Meliaceae), a rich source of rohitukine

Rohitukine, a chromane alkaloid, is a precursor of flavopiridol, a promising anti-cancer compound. Currently in Phase III clinical trials, flavopiridol is a potent inhibitor of several cyclin-dependent kinases (CDKs). Rohitukine was first reported from Amoora rohituka (0.083% dry weight) followed by that in Dysoxylum binectariferum (0.9% dry weight), both belonging to the family Meliaceae. Here, we report incredibly high yields of rohitukine (7% dry weight) in trees of D. binectariferum from the Western Ghats, India. Crude extracts of the tree were found to be highly effective against ovarian and breast cancer lines tested.     

Identification of heterotic crosses based on the combining ability of novel genotypes in opium poppy (<Emphasis Type="Italic">Papaver somniferum</Emphasis> L.)

Opium poppy is one of the most important crops in respect to its alkaloids of pharmacopoel value and seeds for edible purposes. Thus it becomes necessary to develop varieties for dual purposes having high opium and seed yield. To find out the appropriate genotypes and their heterotic crosses for opium yield, seed yield as well as specific alkaloid and their different contributing traits, present study was conducted in diallel mating design using distinct novel genotypes with specific characteristics. The results showed that the genotypes BR-222, 58/1 and BR-005 have potentiality to develop heterotic crosses for particular traits. The crosses BR284 × BR-222, BR316 × 58/1, BR-222 × BR-005 and BR-061 × BR-222 were observed promising for most of the traits. Hybridization of cultivars belonging to distinguished commercial groups propitiates higher heterotic values in the segregating population.