“ Brassica leafy greens” is a general term that includes several important vegetable crops, such as turnip greens ( Brassica rapa L.), mustard greens ( Brassica juncea L.), collards and kale ( Brassica oleracea L. Acephala Group). More than 28
W. Patrick Wechter, Mark W. Farnham, J. Powell Smith, and Anthony P. Keinath
Xi Wang, Genhua Niu, Mengmeng Gu, Paul A. Baumann, and Joseph Masabni
Bending, G.D. Lincoln, S.D. 1999 Characterisation of volatile sulphur- containing compounds produced during decomposition of Brassica juncea tissues in substrate Soil Biol. Biochem. 31 695 703 Borek, V. Morra, M.J. 2005 Ionic thiocyanate (SCN
Robert G. Fjellstrom and Paul H. Williams
Thirty-seven Brassica rapa L. and B. juncea L. lines from nine subspecies were tested for their reaction to two pathotypes of Fusarium yellows (Fusarium oxysporum Schlecht. f. sp. conglutinans (Wr.) Snyd. & Hans. race 1 and F.o. f. sp. raphani Kend. & Snyd. A subset of 16 lines from these same vegetable types were tested for their reaction to four strains of turnip mosaic virus (TuMV-C1, C2, C3, and C4). Resistance to both Fusarium pathotypes was widespread in these Brassica subspecies, whereas resistance to any strain of TuMV was uncommon. The broad availability of resistance to Fusarium yellows and scarcity of resistance to TuMV necessitate different approaches to obtain disease-resistant cultivars.
Andrew J. Price, Craig S. Charron, Arnold M. Saxton, and Carl E. Sams
A study was conducted to quantify volatiles generated from Indian mustard (Brassica juncea L. Czerniak) tissue incorporated into soils under controlled conditions. Mustard residues were incorporated into noncovered and covered soils that varied by texture, temperature, moisture, pH, or sterility (autoclaved or nonautoclaved). Sandy loam soil had 38% more allyl isothiocyanate (AITC) than clay loam soil. AITC concentration in 45 °C soil was 81% higher than in soil at 15 °C, and 56% higher in covered compared to noncovered treatments. The microbial catabolism of AITC was suggested by the result that AITC concentration in autoclaved soils was over three times that measured in nonautoclaved soils. The highest AITC level detected (1.71 μmol·L–1) occurred in the autoclaved covered soil. Several factors also influenced CO2 evolution. At 30 or 45 °C, CO2 concentration was at least 64% higher than at 15°C. The covered soil had over twice the CO2 found in the noncovered soil, and the nonautoclaved soil treatment yielded twice the CO2 measured in the autoclaved soil. There were no main effect differences among soil moisture, soil pH, and soil texture treatments for CO2 concentrations. This information could be helpful in defining ideal soil conditions for field scale experiments. Additionally, this study demonstrates a sampling technique for testing fumigation potential of biofumigation and solarization systems that may have the potential to replace methyl bromide.
Ryan R.P. Noble, C.S. Charron, and C.E. Sams
The development of alternative methods for control of soilborne pathogens is imperative since the U.S. Clean Air Act bans the use of methyl bromide after 2005. One possibility is to exploit the pesticidal properties of compounds released by macerated Brassica tissues. In this study, masked chaffer beetle larvae were placed in sealed 473-mL jars with 335 g of soil amended with 1%, 2%, 4%, or 8% (g·g–1) Brassica tissue. The most prevalent volatile toxic compound of Brassica juncea (PI 458934) is allyl isothiocyanate (AITC). AITC production was measured in the jars at 0.25, 4, 8, 24, and 48 h using a solid-phase microextraction device (SPME) and gas chromatography. After 7 days, larvae mortality was determined. Control treatments included untreated soil, soil amended with 8% tomato plant tissue, soil amended with pure AITC, and untreated soil with an atmosphere of ≈20% O2 and 0% CO2 changing over 48 h to 2% O2 and 20% CO2. AITC levels were positively correlated to larvae mortality. The estimated lethal concentration for 50% kill (LC50) was 3.6 μg AITC/L soil atmosphere. AITC levels may be influenced by Brassica mass added, soil bulk density, and environmental factors including temperature and moisture. B. juncea has a high tissue AITC concentration. However, the mass of Brassica tissue required for insecticidal application against Cyclocephala sp. is also high, between 4% and 8% of soil mass. Development and selection of Brassica species that produce higher concentrations of isothiocyanate would increase the effectiveness of Brassica biofumigation as an alternative to methyl bromide for controlling soilborne insects.
W. Patrick Wechter, Melanie M. McMillan, Anthony P. Keinath, J. Powell Smith, and Mark W. Farnham
A leafy-green mustard ( Brassica juncea L.) cultivar designated Carolina Broadleaf has been released by the Agricultural Research Service of the U.S. Department of Agriculture in 2015. This released cultivar is a narrow genetic-based population of
Kimberly A. Cochran and Craig S. Rothrock
microplot to infest the top 15 cm of soil. Brassica treatments. Brassica green manure treatments consisted of biomass of Indian mustard ( B. juncea ) ‘Fumus’ and ‘Bionute’, and canola ( B. napus ) ‘Jetton’. Rates of 700, 1400, and 4200 g·m −2 aboveground
Dean A. Kopsell, J. Scott McElroy, Carl E. Sams, and David E. Kopsell
B. juncea , the group known as mustard. The mustards are consumed in the southern United States as mustard greens, or are used as a condiment or spice ( Williams and Hill, 1986 ). The three common diploid species in the genus Brassica have
Sandra E. Branham, Mark W. Farnham, Shane M. Robinson, and W. Patrick Wechter
. ( Cintas et al., 2002 ; Keinath et al., 2006 ; Wechter et al., 2007 ), B. juncea ( Keinath et al., 2006 ; Wechter et al., 2007 , 2014 ), Brassica napus L. ( Bull and Rubio, 2011 ; Koike et al., 2007 ), B. oleracea ( Bull et al., 2010b ; Cintas
Phillip D. Griffiths, Laura Fredrick Marek, and Larry D. Robertson
Black rot is a bacterial disease of crucifer species caused by Xanthomonas campestris pv. campestris (Xcc). Xcc is prevalent worldwide and is a destructive disease of Brassica oleracea vegetables such as cabbage, broccoli, and cauliflower