Weed control and crop tolerance to propane flaming as influenced by the time of day

Time of day has been observed to affect flaming efficacy. The basis for the differential plant response is not well understood; however, daily variation in leaf relative water content (RWC) is thought to contribute to the response. Leaf RWC is the ratio of the amount of water in the leaf tissue compared to when fully turgid. To determine the influence of leaf RWC in plant response to propane flaming, greenhouse experiments were conducted during April and repeated in September of 2009. Two crops [4-leaf maize (Zea mays) and second trifoliate soybean (Glycine max)] and two weed species [5-leaf velvetleaf (Abutilon theophrasti) and 6-leaf green foxtail (Setaria viridis)] were flamed with four propane doses of 0, 29, 43 and 87 kg ha⁻¹ at 0, 4, 8 and 12 h after sunrise-HAS. Leaf RWC was measured before treatment application. Flaming treatment was conducted utilizing a hand flamer with one VT 2-23 C vapor phase burner positioned 20 cm above soil surface and angled horizontally at 30°. The propane pressure was 120 kPa and the application speeds were 1.6, 3.2 and 4.8 km h⁻¹. The plant responses evaluated were plant injury and fresh weight at 7 days after treatment (DAT). All plant species were more susceptible to flaming during the afternoon when they had lower leaf RWC at 8 HAS; however, the response of these plants did not differ with the plants flamed at 12 HAS. Green foxtail flamed at 87 kg ha⁻¹ at 0, 8 and 12 HAS had injury of 62, 76 and 82%, respectively. The same response was observed in velvetleaf which had 80% injury when flamed with 87 kg ha⁻¹ at 0 HAS and 93% injury when flamed at 12 HAS with the same propane dose at 7 DAT. Similar trends occurred for maize and soybean suggesting that leaf RWC could be one of the factors affecting plant response to flaming. Practical implication is that flaming operation should be conducted in the afternoon in order to improve efficacy of weed control and reduce propane consumption rate.     

Leaf and neck blast resistance reaction in tropical rice lines under green house condition

Rice blast (Magnaporthe oryzae) is the most destructive and epidemic disease of rice. Use of host resistance is the best alternative for disease management. The leaf and neck blast resistance of 182 rice breeding lines were assessed for leaf and neck blast and classified relative to a susceptible check-Masuli and resistant check-Laxmi, from greenhouse experiment in 2005 and 2006. The test plants were inoculated with 10⁵ conidial suspension/ml of M. oryzae at 21 days old seedlings for the leaf blast, and at neck base for the neck blast. Among them, for leaf blast, 77 rice lines were resistant, 43 were moderately resistant, 39 were moderately susceptible and 23 were susceptible. While among the selected 31 rice lines evaluated for neck blast, 4 lines were resistant, 4 were moderately resistant, 16 were moderately susceptible and 7 were susceptible. Leaf and neck infection was significant and positively correlated (r = 0.30, P = 0.05). The rice lines, Barkhe 1032, Barkhe 1034, Barkhe 1035, Barkhe 1036, Barkhe 2014, Barkhe 2024, Barkhe 3019, Super 3004 were resistant to leaf blast and Barkhe 1006, Barkhe 1032, Barkhe 1035, Barkhe 3004 were resistant to neck blast. The rice lines with identification # 11, 69, 137, 168, 182 from Masuli × MT4 parentage, and Barkhe 3017 were susceptible to both leaf and neck blast. Progenies of Irradiated Pusa Basmati (IPB), Kalinga III/IR64 (KIII/IR64), and Masuli/IR64 were resistant to both leaf and neck blast. However, most progenies from Masuli/MT4 showed susceptible reaction to both leaf and neck blast. Thus, rice lines form the IPB, KIII/IR64 and Masuli/IR64 will be promising resistant sources for rice blast in breeding programme.     

Citric acid loaded nano clay polymer composite for solubilization of Indian rock phosphates: a step towards sustainable and phosphorus secure future

Non-renewable nature of rock phosphate (RP) reserves coupled with open ended nature of P cycle makes it imperative for maximum utilization of available P resources. In this context, use of Indian RPs from Purulia and Udaipur along with citric acid loaded nanoclay polymer composite (CA-NCPC) as P source to costly diammonium phosphate (DAP) was investigated through an incubation experiment followed by a greenhouse experiment with wheat-rice cropping sequence in a Luvisol (pH 5.14, available P 13.5 mg kg^?1). Soil available P, crop yield parameters and dynamics of soil P fractions were taken to judge the efficacy of CA-NCPC in solubilizing RPs. Application of CA-NCPC and DAP resulted in 82% and 69% increase in available P over control, respectively under incubation study. Direct effect of treatment receiving CA-NCPC + RP on yield and P uptake by wheat was comparable with DAP but residual impact of CA-NCPC + RP (16.7 g pot^?1) was better than DAP (13.8 g pot^?1) in rice. The changes in inorganic P fractions were also significant as inclusion of RP increased calcium-P from 16.1 to 61.5 mg kg^?1. Results indicated potentiality of RPs treated with CA-NCPC as an alternate P source which could prove promising amidst P scarcity.     

Variability among isolates of <Emphasis Type="Italic">Fusarium udum</Emphasis> and the effect on progression of wilt in pigeonpea

Soft rot of Chinese cabbage is a disease of great economic importance to the State of Pernambuco, Brazil. The present study aimed to evaluate the effect of two calcium sources in different concentrations (calcium nitrate [Ca(NO₃)₂] at 0, 0.15 and 0.3 g l^?1 and calcium chloride (CaCl₂) at 0, 1 and 5 g l^?1) that were applied through two methods (leaf spraying and soil drenching) on the control of soft rot. Further, it aimed to analyze calcium absorption by the plant and to determine calcium’s role in leaf and cell structure using microscopy. Ca(NO₃)₂ applied by both methods was effective in controlling soft rot caused by Pectobacterium carotovorum subsp. carotovorum, as it reduced the disease by up to 48.5 % when sprayed onto the leaves (0.15 g l^?1). A significant increase in the leaf calcium content was observed only in the plants that were sprayed with higher doses of Ca(NO₃)₂ and CaCl₂. In all of the calcium treatments, light microscopy analyses revealed an increased number of chloroplasts and improved structuring of the palisade parenchyma, while transmission electron microscopy analyses revealed an increased cell wall thickness that was especially evident for the 0.15 g l^?1 Ca(NO₃)₂ treatment applied by leaf spraying and soil drenching.     

Polymorphism of BMPR1B,BMP15 and GDF9 fecundity genes in prolific Garole sheep

Tropical Animal Health and Production - Mutation studies in different prolific sheep breeds have shown that the transforming growth factor beta super family ligands viz. the growth differentiation...     

Application timing and adjuvant type affected saflufenacil efficacy on selected broadleaf weeds

Saflufenacil is a new herbicide being developed for pre-plant burndown and pre-emergence broadleaf weed control in field crops, including maize, soybean, sorghum and wheat. Field experiments were conducted in 2007 and 2008 in northeast Nebraska, USA to describe dose-response curves of saflufenacil applied in mid (early post-emergence, EPOST) and late May (late post-emergence, LPOST) with several adjuvants for spring emerging broadleaf weed control. Dose-response curves based on log-logistic model were utilized to determine the ED₉₀ values (effective dose that provides 90% weed control efficacy) for Convolvulus arvensis, Lactuca serriola, Lamium amplexicaule, Capsella bursa-pastoris, Taraxacum officinale, Thlaspi arvense and Conyza canadensis. In general, weed control efficacy was influenced by application timing and type of adjuvant. EPOST application of saflufenacil resulted better efficacy of saflufenacil compared to LPOST. Addition of spray adjuvants improved efficacy of saflufenacil. For example, 90% control of T. arvense was obtained at EPOST application with 251, 161, 96 and 59 g a.i. ha⁻¹ for saflufenacil applied alone, or tank-mixed with NIS (nonionic surfactant), COC (crop oil concentrate), or MSO (methylated seed oil), respectively. In contrast, the ED₉₀ values with LPOST application were 333, 201, 127 and 79 g a.i. ha⁻¹ for saflufenacil applied alone, or with NIS, COC and MSO, respectively. MSO was the best adjuvant, which provided the most enhancement of saflufenacil. COC was the second best, or similar to MSO, on many weed species. NIS provided the least enhancement of saflufenacil. The ED₉₀ values determined for different broadleaf weed species are within the proposed label dose of saflufenacil.     

Popcorn (Zea mays L. var. everta) yield and yield components as influenced by the timing of broadcast flaming

Farmers are interested in producing popcorn under organic production systems and propane flaming could be a significant component of an integrated weed management program. The objective of this study was to collect baseline information on popcorn tolerance to broadcast flaming as influenced by propane dose and crop growth stage at the time of flaming. Field experiments were conducted at the Haskell Agricultural Laboratory of the University of Nebraska, Concord, NE in 2008 and 2009 using five propane doses (0, 13, 24, 44 and 85 kg ha⁻¹) applied at the 2-leaf, 5-leaf and 7-leaf growth stages. Propane was applied using a custom-built research flamer driven at a constant speed of 6.4 km h⁻¹. Crop response to propane dose was described by log-logistic models on the basis of visual estimates of crop injury, yield components (plants m⁻², ears plant⁻¹, kernels cob⁻¹ and 100-kernel weight) and grain yield. Popcorn response to flaming was influenced by the crop growth stage and propane dose. Based on various parameters evaluated, popcorn flamed at the 5-leaf showed the highest tolerance while the 2-leaf was the most susceptible stage. The maximum yield reductions were 45%, 9% and 16% for the 2-leaf, 5-leaf and 7-leaf stages, respectively. In addition, propane doses that resulted in a 5% yield loss were 23 kg ha⁻¹ for the 2-leaf and 7-leaf and 30 kg ha⁻¹ for the 5-leaf stage. Flaming has a potential to be used effectively in organic popcorn production if properly used.     

Comparison of Two Adsorbent Based de-Bittering Procedures for Neem (<Emphasis Type="Italic">Azadirachta indica</Emphasis> A. Juss) Tea- Effect on Polyphenols,Anti-Oxidant Capacity,Color and Volatile Profile

Bitterness reduction, especially of foods and beverages containing phytonutrients, is one of the biggest challenges in the food industry because bitterness has a deleterious effect on the taste profile of foods and beverages. Neem (Azadirachta indica A. Juss) is a medicinal tree, indigenous to the Indian-subcontinent, whose medicinal properties have led to it being heralded as the tree which is the “panacea for all diseases”. However, neem leaf is extremely bitter, in large part due to its limonoid content, making it unpalatable. The objective of this study was to apply two adsorbent based strategies, namely solid phase extraction (SPE) and Amberlite XAD-16 (AMB) resin, to achieve de-bittering of neem tea and to determine the effects of the de-bittering on the bio-active, color and volatile properties. The solid SPE treatment completely removed the flavonol, quercetin, from neem tea while in Amberlite XAD-16 treated tea (AMB) it was only insignificantly (p > 0.05) reduced. We also observed decreases in total phenolic content and consequently anti-oxidant activities after de-bittering. A 62% mean reduction of limonoid aglycones indicated diminished levels of bitterness. The loss of phenolics lead to a visually appreciable color changes in the treated teas. The de-bittering also leads to a loss of sesquiterpenes, ketones and acids from neem tea. In conclusion, we found that while SPE cartridges were more efficient in removing bitterness, they caused a greater reduction in bio-active compounds than AMB XAD-16 resins, which may ultimately affect the health properties of neem tea.     

Nitrogen-15 balance in transplanted and direct-seeded flooded rice as affected by different methods of urea application

Summary Alternative N-fertilizer management practices are needed to increase productivity and the N-use efficiency of flooded rice (Oryza sativa L.). In the 1987 dry season, a field study using ¹⁵N-labeled urea evaluated the effect of the time and method of fertilizer-N application on grain yield and N-use efficiency in transplanted and direct-seeded flooded rice. Conventional fertilizer application (broadcasting and incorporation) was compared with band placement of liquid urea and point placement of urea supergranules. With band or point placement, the grain yields were significantly greater, and the partial pressure of NH₃ (pNH₃) in the floodwater was significantly reduced. In the transplanted rice, conventional fertilizer-N application gave a 64% total ¹⁵N recovery and 38% crop (grain and straw) recovery. Band placement of liquid urea N resulted in 92% total and 73% crop recovery. In the direct-seeded flooded rice, a conventional N application gave 72% total and 42% crop recovery; band placement, 98% total and 73% crop recovery; and urea supergranule point placement, 97% total and 75% crop recovery.Dedicated to Prof. Dr. K. Mengel, Giessen, FRG, in honor of his 60th birthday.