Kamal Uddin

Characterizing weed populations in different turfgrass sites throughout the Klang Valley of western Peninsular Malaysia.

Abstract A field survey was conducted in 2007 to characterize weed populations in different turfgrass sites throughout the Klang Valley of western Peninsular Malaysia. Sites included golf course putting greens, athletic fields, sod farms, and residential lawns. Weeds present in each site were identified and the data were used to calculate frequency, distribution uniformity, density, relative abundance, and community coefficient values for each species. Seventy-nine weed species, belonging to 16 families, were found. The most species were found on residential lawns, and the fewest were found on golf course putting greens; athletic fields and sod farms ranked intermediately. A total of 19 different weed species were classified as major (relative abundance ≥ 15), and abundance rankings varied by turfgrass area. Greater kyllinga had the highest relative abundance values on athletic fields (45.5) and golf course putting greens (71.5), and the second highest value (21.7) on residential lawns. Forked fringerush and annual sedge had the greatest relative abundance values on residential lawns and sod farms, respectively. Cogongrass was reported on 15% of the residential lawns evaluated. The heterogeneity of weed species composition suggests that control strategies will vary by turfgrass use area. Quantifying weed population dynamics will help researchers delineate integrated weed management strategies to turfgrass managers in Malaysia.

Allelopathic effect of methanol extracts from Tinospora tuberculata on selected crops and rice weeds

Herbicidal potential of aerial parts of Tinospora tuberculata on germination and seedling growth of seven test plant species, namely rice (Oryza sativa L.); two rice weeds, barnyardgrass (Echinochloa crus-galli L.) and weedy rice (O. sativa f. spontanea); and four vegetable crops, lettuce (Lactuca sativa L.), tomato (Solanum lycopersicum L.), carrot (Daucus carota L.), and cucumber (Cucumis sativus L.) were evaluated. Six concentrations of methanol extract (3.12, 6.25, 12.5, 25, 50, and 100 g L−1) were compared with the control (distilled water). The rate of seed germination and the radicle and hypocotyl length of 7-day-old test plant seedlings were reduced as the concentration of extracts increased compared to the control. Generally, the degree of toxicity of extracts derived from the leaves was more than the extracts derived from the stem. Cluster analysis and the concentrations required for 50% inhibition (defined as EC50) of all parameters showed that radicle growth was more suppressed than germination and hypocotyl growth. Lettuce and carrot were observed as the most sensitive plants while rice showed the highest tolerance to both extracts. Moreover, the dicot target plants were affected more severely than the monocots when treated with leaf extract. The chemical composition of the T. tuberculata methanolic extracts was analyzed by a GC–MS system. A total of 92 and 22 constituents (not previously identified) were found in the leaves and stem, respectively. The results showed that 17 of the 92 components in the leaves, as compared to 4 of 22 compounds in the stem, are known as toxic compounds. These results suggest that T. tuberculata contains a significant source of plant growth inhibitors with potential for the development of future natural herbicide.

Nitrogen and phosphorus management for Bambara groundnut (Vigna subterranea) production-A review

Bambara groundnut (Vigna subterranea) has characteristics to grow in the marginal soil and also tolerant into the drought condition and also have potential of nitrogen fixation. Nitrogen is the key plant nutrient that stimulates root and shoot growth. Phosphorus application significantly improves many aspects of plant physiology including photosynthesis, flowering, fruiting and maturation which ultimately result in better yield. Symbiotic nitrogen fixation is a complex process, in which Rhizobium bacteria form a beneficial interaction with a legume crop to fix atmospheric nitrogen and convert it to ammonium for plant uptake. Biological N fixation (BNF) is the natural means to enhance soil fertility status and productivity. Application of nitrogen and phosphorus fertilizer exerted significant effect on root development, photosynthesis, yield contributing character and pod yield of the crop. Bambara Groundnut yields are low due to abiotic and biotic stresses. But with application of nitrogen and phosphorus increase the yield of this crop. It’s seeds contain 63 percent carbohydrate, 19 percent protein and 6.5 percent oil and good source of fibre, calcium, iron and potassium.

Effects of Tinospora tuberculata leaf methanol extract on seedling growth of rice and associated weed species in hydroponic culture

The study was conducted to evaluate the responses of rice and rice weed seedlings (barnyardgrass and weedy rice) at the three-leaf stage to Tinospora tuberculata leaf methanol extract (3.12, 6.25 and 12.5 g L−1) under hydroponic culture. It shows that the leaf methanol extract had various degrees effects depending on target plant species and each tested index (biomass, root length, shoot length, transpiration volume, chlorophyll a, chlorophyll b and carotenoid contents). The effective concentration of the leaf extract capable of reducing 50% of rice growth was higher than those of target weed species. Moreover, the root length was more tolerant to leaf methanol extract in comparison to the other plant parameters measured. A greater reduction was observed in chlorophyll a content compared to chlorophyll b and carotenoid. The results revealed that the reduction of transpiration volume closely coincided with the magnitude of growth inhibition of tested plants. Ultra-fast liquid chromatography analysis revealed 11 of 32 peaks in chemical profile, including benzoic acid, caffeic acid, chlorogenic acid, isoorientin, isovitexin, orientin, p-anisic acid, syringic acid, trans-cinnamic acid, trans-ferulic acid, and vitexin have the same retention time with those peaks of the extract. The amount of compounds was present in the range of between 4 817 and 115.5 mg kg−1 dry weight (DW). The concentration-response bioassay of all 11 individual compounds and their equimolar mixture against the seeds of barnyardgrass revealed their contribution in the allelopahic activity of T. tuberculata leaf extract. The examined compounds and their combination exhibited various degrees of growth inhibitory effects on the early growth of barnyardgrass. Therefore, the specific number, concentration, combination and inhibitory activity of bioactive compounds leads to allelopathy activity of T. tuberculata leaves which could be employable directly as a natural herbicide and its growth inhibitor compounds can be used as a template for producing new herbicides.

Distribution of weedy rice escape variants in Clearfield Rice Production System

Weedy rice is made up of the undesirable biotypes of rice with early and easy shattering characteristics, which causes a major yield reduction in direct-seeded rice in Malaysia. Thus, a series of survey were conducted in the selected Clearfield rice fields in the four townships, namely, Kampung Sungai Manik, FELCRA Seberang Perak, Kampung Mampas and Kampung Sungai Mati in the Peninsular Malaysia from April 2012 and April 2013 to study the dominance and abundance of weedy rice escaping Clearfield Production System (known as weedy rice escape). The survey was done according to the quantitative survey method by using standardized quadrat. A total of 1240 and 813 weedy rice escapes in dry/off season 2012 and main season 2012 were identified in all surveyed rice fields, respectively. Kampung Mampas indicated the highest dominance of weedy rice escapes, while FELCRA Seberang Perak recorded the lowest dominance in both the planting seasons. From the farmers’ complaint, poor rice management and weeding practices were the major factors that contributed to weedy rice escape in the fields.

Application of silica to suppress the disease infestation of Phytium ultimum and increase growth of Bermudagrass cv Satiri

An experiment was conducted at glasshouse of Unit Latihan Turf, Taman Pertanian, Universiti Putra Malaysia, to find out the effect of different doses of silica (Si) on growth of Bermuda cv Satiri and to suppress the Pythium ultimum disease infestation. Two sources of silica were used in this study: Turf speed® (T. speed), content 15% of potassium silicate (K ₂SiO ₃) and Tune up®, content 10% Sodium Silicate (SiO 2). Percent disease severity, shoot density, total dry weight, root and shoot dry weight and root-shoot ratio were determined. Application of Turf speed 10 ml L -1 produced the highest shoot density (125/25 cm≤), shoot dry weight (2.49 g) and total dry weight (4.76 g). Tune up (1.0 ml L -1 ) and without application of any Si produced the highest disease severity (73.69%) and (69.75%) respectively, while, Tune up (1.0 ml L -1 ) produced the lowest disease severity (44%). The study proved that application of T. Speed (10 ml L -1 ) and Tune up 2.0 ml L -1 produced good growth, quality and reduced P. ultimum infection of Bermuda cv Satiri.