Study of heterosis in Bangladeshi chilli (Capsicum annuum L.) landraces

Chilli is an important cash crop in Bangladesh but average yield is very low (0.89 t ha-1) and genetic potentiality of Bangladeshi chilli landraces for hybrid variety development has not been evaluated. The objective of this study was to find out heterotic behavior following Gardner and Eberhart model (1966) II. Six different homozygous divergent parents CCA 2, CCA 5, BARI Morich 1, CCA 11, CCA 15 and CCA 19 were used to estimate heterosis. A significant amount of heterosis was present in yield and yield contributing traits. Estimate of variety heterosis for yield per plant was significantly positive in CCA 5 and BARI Morich 1. In BARI Morich 1, the significant and positive variety heterosis for yield per plant was associated with significant and positive estimates of heterosis for number of fruits per plant and number of seeds per fruit, suggesting that these yield traits contributed to the final heterosis manifested through yield. Indigenous×exotic crosses showed significant amount of heterosis. It is possible to emphasize indigenous×exotic crosses for good fruit yield, particularly to be used as commercial hybrids. Hybrids of BARI Morich 1×CCA 19 and CCA 5×BARI Morich 1 showed better performance

Optimizing seed rate for summer mungbean varieties

An experiment was conducted at the Agronomy Field Laboratory, Bangladesh Agricultural University, Mymensingh from March to June, 2007 to investigate the effect of cultivar and seed rate on morphological characters, yield attributes and yield of summer mungbean. The experiment comprised four varieties viz., BINA moog2, BINA moog5, BINA moog6 and BINA moog7 and four seed rates viz. 30, 40, 50 and 60 kg ha-1. The experiment was laid out in a randomized complete block design with four replications. Results revealed that variety and seed rate had significant effect on the studied crop characters and yield. The variety BINA moog7 showed superiority in relation to plant height, number of branches and effective pods per plant, number of seeds pod-1 compared to other varieties, which resulted in the highest seed yield both per plant and per hectare. The plant height, stover yield and number of non-effective pods per plant increased with the increase in seed rate, while branch number, number of effective pods per plant, seeds per pod, 100-seed weight, as well as seed weight per plant decreased with increasing seed rate. The higher number of branches and effective pods per plant, number of seeds pod, 100-seed weight and seed yield per plant were recorded at the rate of 30 and 40 kg seeds ha-1 and the lowest values for the above parameters were observed at the rate of 60 kg seeds ha-1. But per unit area basis, the highest seed yield was recorded in 40 kg seeds ha-1 followed by 50 kg seeds ha-1 due to accommodation of higher number of plants. BINA moog7 interacted favorably with the seed rate of 30 kg ha-1 to produce the highest seed yield

Diversity of weed communities under different water regimes in bertam irrigated direct seeded rice field.

Experiments were initiated at MARDI Bertam Rice Research Station in Penang in the dry season of 2004 and main season 2004/2005 to study the effect of different water regimes on diversity of weed species. Plots receiving continuous flooded treatment (T1) and flooding up to panicle initiation (T2) significantly suppressed weed population to approximately 18 – 58% and reduced weed biomass to 14 – 57% as compared to the highest values in continuous field capacity treatment (T5) at all sampling dates (30, 60 and 90 DAS) in both planting seasons. Across water regime treatments the weed composition comprised of 11 weed species in the dry season and 10 weed species in the main season. Broadleaved weeds, especially Monochoria vaginalis and Limnocharis flava were the most dominant weeds in most water regime treatments. The SDR values of broadleaved weeds in the dry season were 48.7, 46.4, 44.2, 40.7 and 35.8% for T2, T1, T3 (flooding for the first month), T5 and T4 (continuous saturation), respectively. In the main season, the SDR values for the broadleaved weeds increased to 79.5, 68.2, 62.4, 62.2, and 50.57% for T2, T1, T3, T4 and T5, respectively. Fimbristylis miliacea and Cyperus iria were dominant in the dry season with SDR values of more than 34% in all water regime treatments, but decreased to less than 23% in the main season. For grasses, comprising of mostly Echinochloa crus-galli, Echinochloa colona and Leptochloa chinensis, SDR values of more than 20% were recorded in T4 and T5 in the dry season, while in the main season SDR values of between 21 – 34% were observed in treatments T1, T3and T5

Evaluation of phenolics, capsaicinoids, antioxidant properties, and major macro-micro minerals of some hot and sweet peppers and ginger land-races of Malaysia

There are compelling evidences that oxidative stress plays important role in age‐related neurodegenerative diseases and natural food‐derived dietary antioxidants appear to be the first line of defence to take care of the oxidative stress. The analysis results of this study showed that Cili Burung of the hot pepper landraces contained the highest amount of TPC (1.00 mg/g DW), TFC (0.17 mg/g DW), capsaicinoids (0.05 mg/g), and the highest FRAP activity (439 mg/g DW). However, DPPH assay revealed the highest DPPH scavenging activity (IC50 = 250 μg/ml) in Halia Bara rhizome. Rhizomes of both landraces of ginger showed a significant amount of capsaicinoids. Hot pepper Cili Ungu (5.50 g/kg) and sweet pepper Cili Kulai had the highest P contents (~5.5 g/kg). Halia Bentong ginger rhizome had the highest content of K (33.84 g/kg); however, Halia Bentong ginger roots had remarkably greater contents of Ca (10.96 g/kg). Ginger rhizomes and roots had greater contents of micro minerals compared to hot and sweet chili peppers. Ginger roots contained good amounts of bioactive compounds and mineral nutrients indicating its commercial value

Impact of pre-sowing treatment on seed germination and seedlings growth attributes of Calamus longisetus Griff. at nursery and field conditions

The paper describes the germination behaviour of Calamus longisetus Griff. seeds under three different pre-sowing treatments and seedlings growth performance in nursery and field condition. Whole fruits, seeds with pulp and cleaned seeds were sown in germination trays filled with soils mixed with decomposed cowdung at a ratio of 3:1. The growth performance of the seedlings were determined by transferring the young seedlings (having 2 – 3 leaves) from germination bed to the polybags filled with soil mix followed by outplanting (at 1-year old) in the field. Germination percentage was significantly (p ≤0.001) enhanced by the pre-sowing treatment where the highest germination percentage was in cleaned seeds followed by the seeds with pulp and lowest in whole fruits. The survival percentage was over 91% in the field after one year and the average height 126.2 cm after two years of planting. Clean seeds for nursery raising and one-year old seedlings for outplanting were found suitable for raising successful plantations for the species

A comparison of yield potential and cultivar performance of 20 collected purslane (Portulaca oleracea L.) accessions employing seeds vs. stem cuttings

A glasshouse experiment was conducted in Universiti Putra Malaysia (UPM) to evaluate the regeneration and yield potential in purslane using both seeds and stem cuttings of 20 collected accessions from different locations in Western Peninsular Malaysia. Analysis results revealed significant variations (P< 0.05) for morphological traits viz., plant height, number of main branches, number of nodes, internodal distance, stem diameter, number of leaves, leaf area, number of flowers, root length, fresh and dry weight but no significant difference were observed for physiological traits viz., total chlorophyll, net photosynthesis, stomatal conductance, transpiration, water vapor deficit and for either major micro or macro minerals. Hope our research findings will eliminate the doubt of using cutting methods for purslane propagation and cultivation among producers and consumers and will promote their determination to follow purslane production in this summer at any season and anywhere. To the best of our knowledge, this is the first attempt to evaluate and to detect any significant variations arising in morphological, physiological, and especially mineral nutrition in purslane propagated through cuttings vs. through seeds

Effects of Albizia saman (Jacq. Mull) leaf mulch on vegetative growth of maize (Zea mays L.) and soil chemical properties through biomass transfer

The study presents the effects of Albizia saman (Jacq. Mull) leaves in a biomass transfer as a source of organic fertilizer on the soil chemical properties and vegetative growth of maize (Zea mays) compared with NPK (15-15-15) in greenhouse condition. Albizia saman leaves and NPK (15-15-15) were applied at the rate of 2.5, 5.0 and 7.5 t/ha or 60, 90 and 120 kg/ha respectively, separately or in combination. The findings revealed that application of 2.5 t/ha A. saman leaves produced the maximum values for mean leaf number, leaf area and stem height (7.77, 212.24 cm2 and 49.67 cm, respectively) among the leaf much treatments but were not significantly different from those obtained by applying 90 kg/ha NPK fertilizer (7.86, 225.55 cm2 and 48.78 cm, respectively). However, the maximum number of leaf (8.4), leaf area (240.5 cm2), plant height (54.64 cm) and biomass (16.17 g) were obtained from the combination of 2.5 t/ha leaves with 90 kg/ha NPK. There was significant improvement in the soil chemical status with the application of 2.5 or 5.0 t/ha A. saman leaves whereas the application of 5.0 t/ha A. saman leaves experienced the highest value for organic carbon (3.56%), total nitrogen (0.23%) and potassium (0.16 mg/kg) and 2.5 t/ha leaves gave the highest value for available phosphorus (22.30 mg/kg). It can, therefore, be inferred that the application of 2.5 t/ha A. saman leaves as source of organic fertilizer will give a better growth of maize and the combination of this quantity with 90 kg/ha of NPK would give better results in crop yield and maintenance of soil fertility

Effects of flowering behavior and pod maturity synchrony on yield of mungbean [Vigna radiata (L.) Wilczek].

A number of experiments were set up to assess the flower production and flowering pattern in synchrony with pod maturity and seed yield in twelve mungbean genotypes. Synchrony of pod maturity was measured based on percentage of mature pods at first harvest, where; synchrony (>90% mature pods), partial synchrony (80-90% mature pods) and asynchrony (<80% mature pods). Results revealed that genotypes that produced maximal opened flowers within 10-15 days, and ceased flowering within 15-20 days after first flowering (DAF), have synchrony in pod maturity. Additionally, seed yield was strongly correlated with the number of opened flowers and number of produced mature pods. Four genotypes showed synchrony in pod maturity which accompanied with cessation of flower production at 10-15 DAF, but produced lower yields due to fewer opened flowers. In contrast, the remaining genotypes showed partial synchrony or asynchrony in pod maturity due to longer flowering durations, with higher number of opened flowers and seed yield. These results indicate that synchrony in pod maturity and seed yield in mungbean is inversely related

Sedge weeds control in tropical turf using sea water

Research was designed to reduce herbicide use by replacing post emergence herbicides with readily available sea water to control tropical weeds. Results showed that 5 species viz., Cyperus compressus L., Cyperus iria L., Fimbristylis miliaceae Vahl., Fimbristylis ovata J. Kern. and Scirpus juncoides Roxb. were very susceptible and effectively controlled (100%) with 72 dS/m salinity treatment, but. 2 species viz. Cyperus aromaticus Ridley. and Cyperus rotundus L. were extremely tolerant to the salinity level of 72 dS/m

Effects of deforestation on physicochemical properties and microbial population of soils in a South-East Asian tropical forest

The study was conducted in deforested land and adjacent natural forest in Chittagong Forest South Division, Bangladesh, to explore the effects of deforestation on physico-chemical properties of soil and the soil microbial population. Soil samples from surface (0-10 cm depth) or subsurface (10-20 cm depth) of two hill positions (top and bottom) of deforested land and an adjacent natural forest were collected and analysed for their physico-chemical properties and microbial population. The study reveals that there was no significant (p≤0.05) difference in soil texture for soil surfaces or hill positions between the deforested land and natural forest. However, significantly (p≤0.05) low moisture content and high pH was observed in both the surfaces and hill position in deforested land compared to the natural forest. The microbial community i.e., the fungal and bacterial population was also significantly (p≤0.05) lower in both surfaces (0-10 cm and 10-20 cm) of hill positions in the deforested land compared to natural forest. Fungal population ranged from 59 to 76 million g-1 and 78 to 153 million g-1 of dry soil in deforested land and in natural forest, respectively, whereas bacterial population ranged from 70 to 146 million g-1 in deforested land and from 127 to 218 million g-1 in natural forest. A total of seven genera of fungi were primarily identified from the soils of natural forest and six from the deforested land. The six common genera of identified fungi in both the land used were Mucor, Aspergillus, Rhizopus, Fusarium, Penicillium and Trichoderma and the different one was Colletotrichum from the natural forest. Three genera of bacteria coccus, Streptococcus and Basillus were noticed in natural forest and two genera (coccus and Streptococcus) were recorded from deforested land