Estimating yield of sorghum using root zone water balance model and spectral characteristics of crop in a dryland Alfisol

This study investigated the relationship between sorghum grain yield for a range of soil depths, with the seasonal crop water stress index based on relative evapotranspiration deficits and spectral vegetation indices. A root zone water balance model was used to evaluate seasonal soil water fluctuations and actual evapotranspiration within a toposequence; soil depth varied between 30 and 75 cm and available water capacity ranged from 6.9 to 12.6% (v/v, %). An empirical model was used to determine root growth. Runoff was estimated from rainfall data using the curve number techniques of the Soil Conservation Services, combined with a soil water-accounting procedure. The high r² values between modeled and observed values of soil water in the root zone (r² > 0.70, significant at P < 0.001) and runoff (r² = 0.95, significant at P < 0.001) indicated good agreement between the model output and observed values. Canopy reflectance was measured during the entire crop growth period and the following spectral indices were calculated: simple ratio, normalized difference vegetation index (NDVI), green NDVI, perpendicular vegetation index, soil adjusted vegetation index (SAVI) and modified SAVI (MSAVI). All the vegetation indices, except for the perpendicular vegetation index, measured from booting to anthesis stage, were positively correlated with leaf area index (LAI) and yield. The correlation coefficient for spectral indices with dry biomass was relatively less than for LAI and yield. Modified SAVI recorded from booting to milk-grain stage gave the highest average correlation coefficient with grain yield. Additive and multiplicative forms of water-production functions, as well as water stress index calculated from water budget model, were used to predict crop yield. A multiple regression was carried out with yield, for the years 2001–2003, as the dependent variable and MSAVI, from the booting to the milk-grain stage of crop and relative yield values, calculated using both additive and multiplicative water production functions as well as water stress index, as the independent variables. The multiplicative model and MSAVI, recorded during the heading stage of crop growth, gave the highest coefficient of determination (r² = 0.682, significant at P < 0.001). The multiple regression equation was tested for yield data recorded during 2004; the deviation between observed and estimated yields varied from −6.2 to 9.4%. The water budget model, along with spectral vegetation indices, gave satisfactory estimates of sorghum grain yields and appears to be a useful tool to estimate yield as a function of soil depth and available water.     

Promoting native trees in shade coffee plantations of southern India: comparison of growth rates with the exotic <Emphasis Type="Italic">Grevillea robusta</Emphasis>

Traditional shade coffee plantations of Kodagu district, in the Western Ghats of southern India, harbor a high density and diversity of trees. Local farmers appreciate native biodiversity, but plantation economics and public policies drive them to gradually replace the original diversified cover with exotic shade trees such as Grevillea robusta, which grows fast and can be easily traded as timber. In order to identify and recommend native timber trees with fast growth rates, we compared the growth performance of four common native species against that of G. robusta, by fitting steel dendrometer bands on 332 shade trees. Results showed that in general G. robusta had the fastest growth rates, but large trees of the native Acrocarpus fraxinifolius had faster growth in the wet western side of the district. Computer projections of long term performance showed that most species were influenced by bioclimatic zone. Species-specific local environmental effects also occurred, including competition from coffee bushes for A. fraxinifolius, influence of aspect for G. robusta, and management block effects for Lagerstroemia microcarpa. Our results show that native species potentially could produce timber at rates equivalent to those of exotic species. However, as in many tropical countries, data on growth rates of native trees within mixed-cover plantations are scarce and this study underlines the urgent need to screen for fast-growing species. Such information provides a strong basis for recommending appropriate changes in public policies that would improve tree tenure security and encourage farmers to grow more native species.     

Protective effect of Spirulina fusiformis on chemical-induced genotoxicity in mice

Spirulina fusiformis given by oral route to mice at doses of 250, 500 and 1000 mg kg(-1) significantly inhibit the genotoxicity induced by cisplatin and urethane. In addition, a significant reduction in the extent of lipid peroxidation with concomitant increase in the liver enzymatic (GPx, GST, SOD, CAT) and non-enzymatic (reduced glutathione) antioxidants were observed.     

Growth CO2 concentration modifies the transpiration response of Populus deltoides to drought and vapor pressure deficit

Cottonwood (Populus deltoides Bartr. ex Marsh.) trees grown for 9 months in elevated carbon dioxide concentration ([CO2]) showed significant increases in height, leaf area and basal diameter relative to trees in a near-ambient [CO2] control treatment. Sample trees in the CO2 treatments were subjected to high and low atmospheric vapor pressure deficits (VPD) over a 5-week period at both high and low soil water contents (SWC). During these periods, transpiration rates at both the leaf and canopy levels were calculated based on sap flow measurements and leaf-to-sapwood area ratios. Leaf-level transpiration rates were approximately equivalent across [CO2] treatments when soil water was not limiting. In contrast, during drought stress, canopy-level transpiration rates were approximately equivalent across [CO2] treatments, indicating that leaf-level fluxes during drought stress were reduced in elevated [CO2] by a factor equal to the leaf area ratio of the two canopies. The shift from equivalent leaf-level transpiration to equivalent canopy-level transpiration with increasing drought stress suggests maximum water use rates were controlled primarily by atmospheric demand at high SWC and by soil water availability at low SWC. Changes in VPD had less effect on transpiration than changes in SWC for trees in both CO2 treatments. Transpiration rates of trees in both CO2 treatments reached maximum values at a VPD of about 2.0 kPa at high SWC, but leveled off and decreased slightly in both canopies as VPD increased above this value. At low SWC, increasing VPD from approximately 1.4 to 2.5 kPa caused transpiration rates to decline slightly in the canopies of trees in both treatments, with significant (P = 0.004) decreases occurring in trees in the near-ambient [CO2] treatment. The transpiration responses at high VPD in the presence of high SWC and throughout the low SWC treatment suggest some hydraulic limitations to water use occurred. Comparisons of midday leaf water potentials of trees in both CO2 treatments support this conclusion.     

Antioxidant and antibacterial activities of aqueous extract of Seabuckthorn (Hippophae rhamnoides) seeds

Seabuckthorn (Hippophae rhamnoides) seeds aqueous extract was screened for antioxidant and antibacterial activities. The antioxidant activities (reducing power, DPPH and liposome model system) showed a good antioxidant activity. The extract was also found to possess antibacterial activity with a MIC values with respect to Listeria monocytogenes and Yersinia enterocolitica found to be 750 and 1000 ppm, respectively. The antioxidant and antimicrobial effects of the extract implicate its potential for natural preservation.     

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.     

Antibacterial activity of Vernonia cinerea

The benzene extract of Vernonia cinerea showed a broad spectrum of antibacterial activity.     

Cell,Tissue Culture,and Gene Transfer Techniques for Tasar (Wild) Sericulture Plants—Introspect and Prospect

The in vitro tissue culture and micropropagation of Terminalia spp.—important sericulture plants—have been well established. The rapid and repeatable in vitro response to plant growth regulator treatments has emerged as an essential complement of transformation studies for these plant species. We address in our studies with Terminalia arjuna and T. bellerica, host plants of tasar silkworm that are important also as ethnopharmacological plants. In this article, tissue culture regeneration strategies, advancements, and improvements in genetic transformation of Terminalia species are reviewed. Finally we propose conclusions and future prospects for these economically important sericultural tree species.     

Marker assisted introgression of bacterial blight resistance in Samba Mahsuri,an elite indica rice variety

Samba Mahsuri (BPT5204) is a medium slender grain indica rice variety that is very popular with farmers and consumers across India because of its high yield and excellent cooking quality. However, the variety is susceptible to several diseases and pests, including bacterial blight (BB). We have used PCR based molecular markers in a backcross-breeding program to introgress three major BB resistance genes (Xa21, xa13 and xa5) into Samba Mahsuri from a donor line (SS1113) in which all the three genes are present in a homozygous condition. At each backcross generation, markers closely linked to the three genes were used to select plants possessing these resistance genes (foreground selection) and microsatellite markers polymorphic between donor and recurrent parent were used to select plants that have maximum contribution from the recurrent parent genome (background selection). A selected BC₄F₁ plant was selfed to generate homozygous BC₄F₂ plants with different combinations of BB resistance genes. The three-gene pyramid and two-gene pyramid lines exhibited high levels of resistance against the BB pathogen. Under conditions of BB infection, the three-gene pyramid lines exhibited a significant yield advantage over Samba Mahsuri. Most importantly, these lines retain the excellent grain and cooking qualities of Samba Mahsuri without compromising the yield as determined in multi-location trials. This work demonstrates the successful application of marker-assisted selection for targeted introgression of multiple resistance genes into a premium quality rice variety. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. R. M. Sundaram and M. R. Vishnupriya have contributed equally to this work.     

Foliar disease resistant and productive mutants from the introgression lines of peanut (Arachis hypogaea)

With an objective of developing the induced mutants for superior productivity and resistance to foliar diseases in peanut, two introgression lines (IL-3 and IL-4) derived from ABK genomes of peanut were subjected to gamma and sodium azide mutagenesis. Evaluation of M₁, M₂ and M₃ generations could identify foliar disease resistant and productive mutants. Large-scale evaluation of M₄ mutants during the rainy season of 2017 confirmed the superiority of 12 mutants over the respective parents and the best check (GPBD 4). The selected mutants were resistant to leaf spots (early and late) and rust diseases, and significantly more productive than the parents and GPBD 4. ddRAD-Sequencing of these mutants identified the single nucleotide polymorphisms (SNPs) when compared to their parents. The genes harbouring these structural mutations were also identified. However, no copy number variations (CNVs) were observed between the mutants and the parents. The selected mutants carried resistant-type alleles at the marker loci linked to foliar disease resistance. These promising mutants (M₈) are currently under initial trials of variety development for commercial release.