High frequency plantlet regeneration from nodal segment culture of female <Emphasis Type="Italic">Momordica dioica</Emphasis> (Roxb.)

An in vitro propagation method for female plants of Momordica dioica (Roxb.) has been established. The nodal segments were harvested and the cut ends of the explants were sealed with wax and then surface sterilized and cultured. Bud breaking occurred on Murashige and Skoog’s (MS) agar-gelled medium + 2.0 mg L⁻¹ 6-Benzylaminopurine (BAP) + 0.1 mg L⁻¹ Indole-3 acetic acid (IAA). The cultures were amplified by passages on MS medium supplemented with 1.0 mg L⁻¹ BAP + 0.1 mg L⁻¹ IAA. Further, shoot amplification (29.2 shoots per vessel) was achieved by subculturing of in vitro regenerated shoot clump on MS medium + 0.5 mg L⁻¹ BAP + 0.1 mg L⁻¹ IAA. The micropropagated shoots were subsequently transferred for root formation on half-strength MS medium + 2.0 mg L⁻¹ Indole-3 butyric acid (IBA) with 89% success rate. The in vitro-regenerated shoots were also rooted ex vitro with 34% success. These plantlets were hardened in the greenhouse and transferred to the field. The established protocol is suitable for true to type cloning of mature female plant of M. dioica.     

QTL identification of yield-related traits and their association with flowering and maturity in soybean

Two soybean recombinant inbred line populations, Jinpumkong 2 × SS2-2 (J × S) and Iksannamulkong × SS2-2 (I x S) showed population-specific quantitative trait loci (QTLs) for days to flowering (DF) and days to maturity (DM) and these were closely correlated within population. In the present study, we identified QTLs for six yield-related traits with simple sequence repeat markers, and biological correlations between flowering traits and yield-related traits. The yield-related traits included plant height (PH), node numbers of main stem (NNMS), pod numbers per plant (PNPP), seed numbers per pod (SNPP), 100-seed weight (SW), and seed yield per plant (SYPP). Eighteen QTLs for six yield-related traits were detected on nine chromosomes (Chrs), containing four QTLs for PH, two for NNMS, two for PNPP, three for SNPP, five for SW, and two for SYPP. Two highly significant QTLs for PH and NNMS were identified on Chr 6 (LG C2) in both populations where the major flowering gene, E1, and two DF and DM QTLs were located. One other PNPP QTL was also located on this region, explaining 12.9% of phenotypic variation. Other QTLs for yield-related traits showed population-specificity. Two significant SYPP QTLs potentially related with QTLs for SNPP and PNPP were found on the same loci of Chrs 8 (Satt390) and 10 (Sat_108). Also, highly significant positive phenotypic correlations (P < 0.01) were found between DF with PH, NNMS, PNPP, and SYPP in both populations, while flowering was negatively correlated with SNPP and SW in the J × S (P < 0.05) and I × S (P < 0.01) populations. Similar results were also shown between DM and yield-related traits, except for one SW. These QTLs identified may be useful for marker-assisted selection by soybean breeders.     

Flow cytometric analysis of nuclear DNA content,mitotic chromosome number and protein separation by SDS-PAGE in three accessions of African locust bean (<Emphasis Type="Italic">Parkia biglobosa</Emphasis> Benth.)

Nuclear DNA of three accessions of Parkia biglobosa collected from three locations in northern Cross River State was investigated using a Patec PA II flow cytometer equipped with an argon ion laser (488 nm), and pictures of mitotic chromosomes were taken using a digital micro-camera (Canon) placed on the eye piece of a binocular microscope at 100X oil immersion. Metaphase chromosome counts of 2n = 22 for accessions A and C and 2n = 24 for accession B, were obtained and through flow cytometry, the three accessions were confirmed to be diploids. The nuclear DNA content and genome size for the accessions were 1.5085, 1.489, and 1.5266 pg (737.7054, 728.121, and 746.5074 Mbp) for accessions A, B, and C, respectively. In another experiment, leaf samples from greenhouse-germinated seeds were analyzed for variation in the banding pattern of the protein by SDS-PAGE in the three accessions. Protein was resolved into three banding groups according to their electrophoretic mobility: slow, medium, and fast, clustering between 100–200, 40–70, and 10–25 kDa, respectively. There was 76% similarity in the banding pattern between the accessions.     

Application of DNDC model to estimate N<Subscript>2</Subscript>O emissions from green tea fields in Japan

Heavy doses of N fertilizers are commonly applied to green tea fields in Japan, and cause large amount of nitrate leaching in ground water and emission of ammonia and nitrous oxide (N₂O) to the atmosphere. The Denitrification and Decomposition (DNDC) model was tested against experimental data on N₂O emissions from the tea field in Nishio, Aichi, Japan. There were reasonable agreements between the simulated and measured values of N₂O emissions for this site. The model was then applied for estimating the environmental impacts as affected by farm management practices, climate change, and soil properties. The model results were assessed with respect to major indicators of agro-ecosystems including crop yield, soil organic carbon sequestration, nitrate leaching loss, and N₂O emission. The results indicated that use of compost significantly reduced nitrate leaching and N₂O emissions in comparison with N fertilizer. When soil pH and texture shifted to non-acidic and coarser soil, N₂O emission increased; and a change in temperature and precipitation affected N₂O emission, nitrate leaching, and SOC sequestration. This study thus revealed the biogeochemistry model as a powerful tool in addressing the complex efficacy of the alternative farm management practices in tea fields across various climate and soil conditions.     

Greenhouse evaluation and inheritance analysis of transgenic cotton expressing <Emphasis Type="Italic">PTM3</Emphasis>, a MADS-box gene of Aspen

The PTM3 (MADS-box) gene characterized from flower of Aspen was ectopically expressed in cotton and was found to result in desirable agronomic traits. Among several transgenic lines, the PTM3 cotton event-10 was found to flower significantly earlier than the control and yield better [Ramachandran et al. (2011)]. We report our findings on performance based on greenhouse evaluation and inheritance of PTM3 cotton event-10. The T₁ progeny of event-10 were grown in pots under RBD design. The progeny were confirmed by kanamycin imbibition test, PCR, and GUS assay which showed the segregation of transgene at about 3:1 ratio. GUS assay was performed with pollen from all transgenic plants; plants that expressed gus in all pollen versus those that showed segregation for expression were found to be at a ratio of 1:2. Similar to observations made in the T₀ generation of event-10, the agronomic evaluation of T₁ progeny exhibited, on an average, earliness of 13 days in flowering, 13.5 days in crop maturity, and 22% of yield enhancement. The T₂ progeny of homozygous lines were grown on field soil in the greenhouse under strip trial design to see the effect as observed from potted plants of T₁ progeny. Inheritance of transgene cassette to T₂ progeny was confirmed by the same tests used to analyze T₁ progeny. As exhibited by T₀ and T₁ progenies, the T₂ progeny also showed earliness of 8 days in flowering, 12 days in crop maturity, and 17% of yield enhancement. The data generated from the progeny over two generations confirms that the PTM3 cotton event-10 is superior in agronomic characters as compared to non-transgenic cotton and is of interest for breeding shorter duration varieties with improved yield.     

Varietal difference in physicochemical properties of pigmented rice varieties

The physicochemical properties of pigmented (Midorimochi, Jeokjinjubyeo, and Heukmichalbyeo) and non-pigmented (Hwayoungbyeo) rice varieties were investigated. Starch from non-pigmented rice consisted mainly of large polyhedral granules that were more loosely packed than those of the non-pigmented sample. Pigmented rice showed higher linoleic acid content (36–40%) and hydrolysis rate (63–79%) but lower oleic acid content (35–39%), blue value (0.05–0.17), and viscosity values than the non-pigmented one. Significantly higher mineral content, blue value, and pasting and viscosity values were observed in the Jeokjinjubyeo sample compared to those of the other pigmented rice samples. The Midorimochi variety, on the other hand, exhibited the highest total amino acid (816.82 ng mg⁻¹) and sugar (0.15–3.35 μg g⁻¹) contents and the lowest pasting and viscosity values. No substantial difference in the X-ray diffraction pattern was observed among the samples. Results of this study could serve as baseline information for the quality evaluation of three pigmented rice cultivars and provide a better understanding of their potential uses and food industry applications.     

Estimating canopy cover from color digital camera image of rice field

Canopy cover (CC) is a good predictor variable for plant growth parameters such as leaf area index and aboveground biomass. A nondestructive, low-cost, and convenient method is presented for estimating CC using digital camera image analysis. CC was estimated by the ratio of plant pixels to total pixels of digital camera image of rice field. To determine the criteria for segmenting the rice plant from variable soil background, three mosaic images for rice plant, flooded/bare soil, and algae-infested background were prepared from digital camera images that were taken in various field conditions. An image analysis program was developed in Visual Basic to extract red, green, and blue (RGB) features from the mosaic images, calculate RGB-based color indices, and compute the minimum segmentation error for separating rice plant from background. When judged by the segmentation error, modified excessive green index (MEGI) showed the highest potential for segmenting rice plant from flooded/bare soil background, followed by normalized green (g) and excessive green index (EGI). At the threshold MEGI value of 0.03, the segmentation error was the lowest as 0.13%. Any single index considered was not satisfactory in segmenting rice plant from algae-infested background. However, a discriminant function of 1.2553EGI + 0.01735G − 0.01474B was successful in segmenting rice plant from flooded/bare soil and algaeinfested background with segmentation errors of 0.34 and 1.17%, respectively. CC for four rice varieties from tillering to booting stage was estimated based on the threshold value of MEGI and discriminant function and also manually using commercial software. Both estimates of CC showed good relationship of r² = 0.94, suggesting that a digital camera could be used efficiently for measuring the CC of rice field.     

Why invest in minor projects in sub-Saharan Africa? An exploration of the scale economy and diseconomy of irrigation projects

It is well-known that major irrigation projects have a strong scale economy, handicapping irrigation development in sub-Saharan Africa (SSA) because of the difficulty in formulating large-scale projects. Using project-level investment cost and performance data of major and minor irrigation projects, this paper examines the causes of the economy of scale phenomenon. We find that strong scale economy exists not only for major but also for minor projects, i.e., small- and micro-scale, projects. This is largely because of the existence of indivisible overhead costs such as high-opportunity-cost human resources for planning, designing and engineering management and supervision. We also find that large differences between major and minor projects in the absolute level of overhead as well as construction costs creates a strong scale diseconomy and results in better performance of minor projects. The advantage of minor projects holds even when their higher risk associated with the water source is taken into consideration. We argue that there is an urgent need to promote irrigation development in SSA through developing minor projects, and to reduce the heavy burden of overhead costs by developing the capacity of human resources at the national, local and farmer levels in the fields of irrigation engineering, irrigation agronomy, institutional development, and micro water management technologies.     

Tank performance and multiple uses in Tamil Nadu,South India–comparison of 2 time periods (1996–97 and 2009–10)

Irrigation tanks in India are common property resources. Tanks provide not only for irrigation, but also forestry, fishing, domestic water supply, livestock, and other uses. Using empirical results from a study of tank performance from 80 tanks in Tamil Nadu, South India in two time period: 1996-97 and 2009-10, this paper evaluates tank irrigation system performance in terms of economic output and revenue generation forirrigation and other uses. The results indicate that irrigation and other productive uses put together raised the total value of output at tank level by 12 % in 1996-97 and just 6 % in 2009-10. This may suggest that tank multiple use values are small and getting smaller, and therefore not worth consideration. However, it was also found that, while declining in absolute terms, non-irrigation uses provided the majority of tax revenues and still more than cover government's operation and maintenance expenditure (O&M) budget. This finding provides another reason to consider multiple use values and their linkage with overall system viability.     

Modelling scenarios to identify a combined sediment-water management strategy for the large reservoirs of the Tuyamuyun hydro-complex

This paper introduces a combined modelling approach using a simple water budget model (THC-model) and a 3D reservoir sedimentation model (MOHID Water) to adapt reservoir operation and visualise their effects on the sediment deposition. By this, an effective combined sediment-water management can be identified under semi-arid conditions for dry, median and wet years. Results are presented for the reservoirs of the Tuyamuyun Hydro-Complex (THC), which is located in the lower Amu Darya River. The determination of the actual and usable reservoir storage volume shows that siltation will significantly adversely affect the ability of the in-stream Channel Reservoir to regulate seasonal demand for both irrigation and municipal water supply. However, modelling scenarios results confirm the effectiveness of adapted operation rules for the THC reservoirs and show that the operation of large dams could be modified according to a combined sediment-water management. The experience gained during this study emphasizes the fact that the concept of a combined reservoir management of sediments as well as water can be an efficient measure to improve the sustainable long-term use of reservoirs and to contribute towards a safe water supply in water crisis regions.