We examined two aspects of treating plants with a cytokinin-containing seaweed extract (SWE). In the first series of experiments, we tested the hypothesis that immature lima bean (Phaseolus lunatus L.) and tomato (Lycopersicon esculentum Mill.) plants provided with exogenous cytokinins could recover from defoliation by a generalist insect herbivore, Spodoptera exigua (Hübner), more rapidly than plants without cytokinin supplements. However, the SWE inhibited growth of lima beans at all levels of herbivore damage. The SWE neither inhibited nor stimulated growth of tomatoes following defoliation. Because SWE effects largely were neutral for tomato growth, we conducted a second series of experiments to test the hypothesis that SWE treatments alter the attractiveness of tomato foliage to S. exigua larvae. In these experiments, we determined consumption of, and preference for, SWE-treated tomato foliage by S. exigua larvae. Repeated root applications of SWE led to increased consumption and preference by S. exigua. Repeated foliar applications did not alter consumption or preference compared with controls. Spodoptera exigua larvae gained significantly more mass when feeding on SWE-treated foliage compared with controls. While these data indicate that plant responses to exogenous cytokinin-containing materials depend on taxa and application method, the practical uses of SWE appear limited given the negative effects on plant growth and increased attractiveness of treated foliage to herbivores.
Stuart R. Reitz and John T. Trumble
C. A. Mullins, F. D. Tompkins, and W. L. Parks
A 3 year (1976-1978) tillage study was conducted with snap beans (Phaseolus vulgaris L.) and lima beans (P. lunatus L.). Treatments included 2 no-till systems where furrows were opened with a fluted coulter or a vibratory unit, 2 reduced tillage methods with seedbeds prepared with a disk or a powered harrow, and conventional tillage. Tillage method did not affect soil pH at sampled depths. Soil P levels were higher at the 10−15 cm depth with conventional compared to tillage with vibratory unit. Soil K levels were higher at the 5−10 and 10−15 cm depths with conventional tillage. Tillage method did not affect petiole N, K, and Ca concentrations. Petiole P concentrations were lowest with conventional tillage. Petiole Mg concentrations were lowest with the no-till treatments using fluted coulter for snap beans and the vibratory unit for lima beans. Snap bean stand was highest with no-till using the vibratory unit. Tillage method did not affect mean snap bean yield or lima bean stand. Mean lima bean yield was highest with conventional tillage.
Thirty-six climbing accessions of lima bean (Phaseolus lunatus L.) were grown on trellises with minimal chemical inputs in 5 trials at 4 Colombian sites. Mean dry-seed yield of all accessions at all 4 sites was 2.6 mt/ha. Mean yield at the least favorable site was 1.7 mt/ha; at the most favorable site it was 4.8 mt/ha. Although growth was affected adversely on a soil with pH 4.2, the mean yield was 2.5 mt/ha. Mean daily dry-seed productivity rates of all accessions ranged from 15.1 kg/ha/day to 44.1 kg/ha/day for the several locations, in some cases exceeding rates reported for common beans and other legumes at the same location. Mean yield and number of pods per plant varied significantly among sites, dependent upon temperature and soil differences. Days to flower and to dry-seed harvest were relatively stable traits. No relationship was found between yield and seed-coat color. Production constraints were rainfall distribution and acid, phosphorus-deficient soils. These studies demonstrated high productivity of lima beans under adverse and favorable climatic and soil conditions in Colombia
Ed Kee, Tracy Wootten, and James Glancey
Average yields of baby lima beans ( Phaseolus lunatus L.) are consistently lower in Delaware than California and the Pacific Northwest. Comparison of production practices revealed differences in plant populations, soil type, irrigation, relative
Sujatha Sankula, Mark J. VanGessel, Walter E. Kee Jr., C. Edward Beste, and Kathryne L. Everts
Potential increases in the yield of agronomic crops through enhanced light interception have led many growers to consider using narrow rows in lima bean (Phaseolus lunatus L.). However, no information is available on how narrow row spacing affects weed management or fits into an integrated pest management strategy. To address this, field studies were conducted in Delaware and Maryland in 1996 and 1997 to evaluate the effects of row spacing (38 vs. 76 cm) on weed control, and on yield and quality of lima bean. Weed management inputs were also evaluated with labeled or reduced pre-emergence rates of metolachlor plus imazethapyr applied broadcast or banded. Only 76-cm rows were cultivated according to the standard practice for this production system. In general, row spacing, herbicide rate, and herbicide application method had no effect on lima bean biomass or yield, on weed density, control, or biomass production, or on economic return. However, weed control consistency was improved when wide rows were used, even with reduced herbicide rates, possibly because of cultivation. Using reduced herbicide rates and band applications resulted in 84% less herbicide applied without affecting weed control. Chemical names used: 3-(1-methylethyl)-(1H)-2,1,3-benzothiadiazin-4(3H)-one 2,2-dioxide (bentazon); 2-[4,5-dihydro-4-methyl-4-(1-methylethyl-4-(1-methylethyl)-5-oxo-1Himidazol-2-yl]-5-ethyl-3-pyridinecarboxylic acid (imazethapyr); 2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl)acetamide (metolachlor); 2-[1-(ethoxyimino)butyl]-5-[2-ethylthio)propyl]-3-hydroxy-2-cyclohexen-1-one (sethoxydim).
Doyle A. Smittle
Experiments were conducted during 1981 and 1982 to determine the yield and quality responses of lima bean (Phaseolus lunatus L.) cultivars to air temperatures preceding harvest. Temperature conditions and cultivars that produced large lima bean plants at blossom increased seed yields. Quality parameters of seeds after separation into maturity groups by salt brine were influenced by cultivars and air temperatures. Sugar content, green color intensity, and chlorophyll content decreased as seeds matured. Sugar contents of ‘Nemagreen’, ‘Bridgeton’, and ‘Thorogreen’ were greater than ‘Kingston’ at comparable stages of maturity. Sugar content increased when air temperatures during the period of 0–7 days preceding harvest were high. Air temperatures were most closely related to sugar content of mature seeds. Chlorophyll content was closely correlated with tristimulus chlorimeter – a value. The chlorophyll contents at all maturities were reduced by high air temperatures preceding harvest. The average temperature during the period of 7–14 days before harvest had the greatest influence on the chlorophyll content. The influence of air temperatures on chlorophyll content during this period was 3 to 4 times greater for immature (25% total solids) than for mature (35% total solids) seeds, and minimum air temperatures were more closely correlated with chlorophyll contents than were maximum air temperatures. These results indicate that quality (intensity of green color) was affected more by high air temperatures than was seed yield. Chlorophyll contents were more closely related to minimum than to maximum air temperatures, indicating that the effect of high temperature would be increased in humid areas where night temperatures are high.
Timothy G. Porch, Matthew W. Blair, Patricia Lariguet, Carlos Galeano, Clive E. Pankhurst, and William J. Broughton
closely related to other cultivated Phaseolus species, including P. acutifolius (tepary bean), P. coccineus (scarlet runner bean), and P. lunatus (lima bean) as well as to legumes in the Phaseoleae tribe, including Cajanus cajan (pigeonpea
Ping Li, Dong Liu, Min Guo, Yuemin Pan, Fangxin Chen, Huajian Zhang, and Zhimou Gao
bean ( Phaseolus lunatus L.), snap bean ( Phaseolus vulgaris L.), fraser fir [ Abies fraseri (Pursh) Poir.], and certain weeds ( Davidson et al., 2002 ; Gevens et al., 2008 ; Quesada-Ocampo et al., 2009 ). As a heterothallic species, P. capsici
Rakesh Kumar, Mahendra Dia, and Todd C. Wehner
and seed set: Evidence from an experimental population of Cucumis sativus Evolution 38 1350 1357 Harding, J. Tucker, C.L. 1964 Quantitative studies on mating systems. I. Evidence for nonrandomness of outcrossing in Phaseolus lunatus Heredity 19 369
Christopher B. Cerveny, William B. Miller, Thomas Björkman, and Neil S. Mattson
damaging rates of hydration and/or excessive leakage of vital nutrients for growth ( Copeland and McDonald, 2001 ). Pollock and Toole (1966) thought CI in lima bean ( Phaseolus lunatus L.) caused physical damage to cellular membranes resulting in their