The aim of this study was to compare the level of resistance of two new hybrids (F1 Nadira and F1 Jaguar) with the popularly known variety Rio Grande against Pseudomonas solanacearum (causal agentof bacterial wilt) and Erwinia carotovora (responsible of stem rot) under natural conditions. A randomized sample block design containing three treatments (F1 Nadira, F1 Jaguar and Rio Grande) with three repetitions was used. The research took place in Obala subdivision and in University of Yaounde 1, Faculty of Science, Department of Plant Biology, laboratory of Phytopathology and Microbiology in Cameroon during the 2010-2011 growing seasons. The resistance of each variety to the two bacterial diseases was assessed by determining incidence and severity of the diseases. Bacterial symptoms on tomato were identified by visual diagnostic. The incidence and severity of P. solanacearum ranged between 27-39% and 86-92% respectively on all tomato varieties tested; the hybrid F1 Jaguar proved to be less susceptible to bacterial wilt than the control Rio Grande. All the varieties tested had a similar susceptibility with incidence and severity up to 45 and 80% respectively, to E. carotovora. Overall, no significant differences on disease incidence were observed for the two diseases tested. However, the difference in yield between the tested varieties appears to be high. We recommend the use of the hybrid varieties based on their higher production potential of larger fruits and low disease incidence.
A six month screen house experiment was conducted at the Department of Crop Science, University of Benin, Benin City to assess seven forage legumes for N2 fixation and their effects on Amaranthus cruentusin a fluvisol (river sand). Cajanus cajan, Centrosema pascuorum, Leucanea leucocephala, Peuraria phaseoloides, Stylosanthes guianensis, Stylosanthes hamata and Lablab purpureus were fitted into a completely randomized design with three replications. All seeds except Lablab purpureus were scarified and treated with benlate (50% benomyl) before sowing in river sand. Measurements taken at 4- week intervals were root length (cm), root fresh weight (g) and root dry weight (g). At 8 weeks after sowing (WAS), number of nodules, number of effective nodules, nodules fresh weight and nodules dry weight were measured. Shoot and soil nitrogen (g kg-1), leaf chlorophyll index and carbon: nitrogen ratio was assessed at 12 WAS. Amaranthus cruentus followed legumes in sequence and number of days to emergence, plant height, number of leaves, root length, fresh weight of leaves, stems and roots (g) including dry weight of leaves, stems and roots (g) were assessed at 4 WAS. The seven forage legumes accumulated substantial quantities of nitrogen in their shoot (30.5–40.9 g kg-1) and also fixed considerable quantities of nitrogen in the soil (3.2–6.3 g kg-1). Centrosema pascuorum recorded the highest shoot nitrogen (40.9 g kg-1) whereas Stylosanthes hamata fixed the highest quantity of soil nitrogen (6.3 g kg-1). Leucanea leucocephala furnished the best (p = 0.05) root variables while Stylosanthes hamata exhibited the best root nodule characteristics. Carbon: nitrogen ratio ranged from 2.6 to 13.3. Amaranth seeds emerged within 2–7 days after sowing. Growth and yield of amaranth was significantly better in the Lablab-amaranth than other sequences. These positive responses indicate their usefulness for biological nitrogen fixation, forage production and soil fertility improvement. Lablab-amaranth sequence should be developed further for increased vegetable consumption.
A field experiment was conducted at the Agronomy Field Laboratory, Bangladesh Agricultural University, Mymensingh, during the period from February 2012 to May 2012 to investigate the effect of levels of phosphorus (0, 20, 40 and 60 kg ha-1) and boron (0, 1.0, 1.5 and 2.0 kg ha-1) on growth and yield of summer mungbean cv. BINAmung-8. The experiment was laid out in a Randomized Complete Block Design (RCBD) with sixteen treatment combinations having three replications. The results indicated that the crop responded significantly to phosphorus and boron in respect of growth and yield such as plant height, number of branches plant-1, pods plant-1, pod length, number of seeds pod-1, 1000 seed weight, seed yield, stover yield, biological yield and harvest index. In the combination of phosphorus and boron, all the parameters were significant by influence. The highest seed yield (1.19 t ha-1) was obtained from 40 kg P ha-1followed by 60 kg P ha-1 (1.13 t ha-1) and 20 kg P ha-1 (1.10 t ha-1) while the lowest seed yield (1.01 t ha-1) was obtained from the control plot. In case of boron application, the highest seed yield (1.16 t ha-1) was obtained from 1.5 kg B ha-1 followed by 2.0 kg B ha-1(1.14 t ha-1) and 1.0 kg B ha-1(1.09 t ha-1) whereas the lowest seed yield (1.04 t ha-1) was obtained from the control plot. The highest seed yield (1.25 t ha-1) was obtained from the combination of 40 kg P ha-1 × 1.5 kg B ha-1 while the lowest seed yield (0.95 t ha-1) was obtained from the control plot. The results suggest that mungbean crop may preferably be fertilized with a combination of 40 kg P ha-1 × 1.5 kg B ha-1 to obtain maximum seed yield in the agroclimatic condition of the study area.
Aims: To evaluate the spray droplet size spectra of several different agricultural spray nozzles using laser diffraction technology.
Place and Duration of Study: This study was conducted at the United States Department of Agriculture – Agricultural Research Service Aerial Application Technology Research Unit facility in College Station, Texas during April 2014.
Methodology: The spray droplet size spectra of five agricultural spray nozzles utilizing different designs were evaluated in a low-speed wind tunnel. These designs included standard flat-fan, pre-orifice, and air-induction designs. This wind tunnel was equipped with a laser diffraction sensor to analyze spray droplet diameters. A solution of 0.25% v/v nonionic surfactant in water was used to simulate the solution characteristics of many pesticide sprays.
Results: Due to the precision of the droplet sizing equipment, many significant differences in droplet size spectra were detected among all nozzle designs. Increases in median droplet diameters as great as 265% were observed between drift reducing nozzles and standard flat-fan nozzles. Additionally, decreases in the production of drift-prone droplets (≤ 100 μm in diameter) as great as 97.3% were observed with the use of drift reducing designs.
Conclusion: Nozzle designs that utilized a pre-orifice resulting in larger median droplet diameters and fewer droplets of very small diameter. Additional reductions in spray drift potential were achieved with nozzles that utilized an air induction design in conjunction with a pre-orifice.
An experiment was conducted at Agronomy Research Station, Barkacha, Mirjapur 2013-14 in order to control greengram associated weed under Custard apple plantation during Kharif season. The basic objective of the study was to assess the effect of mulching and weed management practices on weed dynamics and greengram yield under agri- horticultural system. Three mulch treatments taken in main plots (no-mulching, dust-mulching and paddy straw-mulching) and five weed control treatments (weedy check, weed free, pendimethalin pre-emergence (PE) 1000 g ha-1, imazethapyr post-emergence (PoE) 100 g ha-1 and pendimethalin (PE) 1000 g ha-1+ imazethapyr (PoE) 100 g ha-1) was randomly allocated to subplots and these were replicated thrice in split plot design on sandy clay loam soils with pH 6.2. The various weeds observed in greengram field were Cyperus rotundus, Echinochloa colona, Cynodon dactylon and Erogrostis pilosa. Among the grasses, Echinochloa colona, in broad leaved weed Erogrostis pilosa and in the sedges Cyperus rotundus was predominant. Dust mulching recorded significantly the highest grain yield (747 kg ha-1), straw yield (1797 kg ha-1) and lowest weed index (1.44%), density and dry weight of Cyperus rotundus, Echinochloa colona, Cynodon dactylon and Erogrostis pilosa, as well as total density and dry weight of weeds over paddy straw mulching. Among herbicidal treatments, sequential application of pendimethalin (1000 g ha-1, PE) + imazethapyr (100 g ha-1, PoE) resulted lower density and dry weight of Cyperus rotundus, Echinochloa colona, Cynodon dactylon and Erogrostis pilosa as well as total density and dry weight of weeds, and recorded significantly highest grain yield (726 kg ha-1) and straw yield (1726 kg ha-1) with minimum weed index (4.15%) followed by same was with the alone application of pendimethalin and imazethapyr, respectively. Weed control efficiency and the regression of yield on it revealed that 1% increase in the weed control efficiency increased the grain yield by 1.873 kg ha-1 and in the straw yield by 2.085 kg ha-1. It is concluded that dust mulching and sequential application of pendimethalin (1000 g ha-1, PE) + imazethapyr (100 g ha-1, PoE) resulted significantly the highest grain and straw yield; and lowest weed index (1.44%), density and dry weight of weeds over other weed management treatments.
DNA-based molecular markers such as Inter Simple Sequence Repeat (ISSR), Sequence-Related Amplified polymorphism (SRAP) and Random Amplified Polymorphic DNA (RAPD) were used in this study to examine the genetic differences among sixteen Iraqi wheat varieties. Seventy three primers out of 177 were reproducible and showed clear amplified bands. The degree of genetic diversity, Polymorphism information content (PIC) and resolving power (RP) were estimated. All the studied molecular markers were informative and showed good ability to classify and distinguish 16 wheat varieties. Total number of polymorphic bands is 134, 221 and 55 for ISSR, SRAP and RAPD respectively. PIC and RP values were 0.259, 0.264 and 0.262 and 9.06, 7.87 and 2.78 respectively. It seems that SRAP marker was the most optimal technique for characterization the of Iraqi wheat varieties. The most efficient primers were Ne ISSR 7 for ISSR; Me4-Em3 and Me4-Em9 primers combination for SRAP; Operon primers K14, K15 and K19 for RAPD. The results of this study can be used to as starting point of the data base for Iraqi wheat varieties to be used in the future development of new varieties in a breeding programs.
Weather condition prevailing during pollination could have some effect on seed set and yield in maize. A controlled pollination experiment was conducted at the Teaching and Research Farm, Ekiti State University, Ado-Ekiti, Nigeria during the early seasons of 2007 and 2008 to investigate the effect of daytime on the performance and seed yield of five maize genotypes viz. two open pollinated, two inbred lines and one hybrid. Hand-pollination was done on an hourly basis between 09.00 to 18.00 hours which constituted the treatments. The ten treatments were laid out in a Randomized Complete Block Design with three replicates. In all the experimental units, five plants were bulk pollinated for each of the time treatment. Results indicated differential responses of the genotypes to time of pollination. When averaged across the five genotypes, there were significant (p<0.05) differences in cob length, weight of 100 seeds weight, and seed yield per cob for the two years whilst cob diameter and number of kernels per row were only significant in 2008. Hand-pollination of maize can be done between 09.00 and 18.00 hours, however, the optimum performance was obtained for cob and seed traits when pollination was done between 10.00 and 12.00 hours, There was 36.65% reduction in seed yield per cob when pollination was delayed till 16.00 hours compared with when done at 10.00 in 2007 and 32.94% reduction between 11.00 and 17.00 hours in 2008. The rate of decline can be minimized when pollination is delayed till 18.00 hours when temperatures are relatively low, which implies that perhaps the most determining factor that precludes pollination is temperature which is comparatively high between 13.00 and 17.00 hours. Furthermore, suboptimum performance was observed when pollination was done at 09.00 hours possibly due to the dampness of the pollen which may impair pollen shedding.