( Watada and Morris, 1967 ). Like with other nonclimacteric fruits and fruit–vegetables, green beans produce very low quantities of ethylene postharvest ( Wills and Kim, 1996 ). For many nonclimacteric fruits, the impact of ethylene is generally believed to
MiAe Cho, Brandon M. Hurr, Jiwon Jeong, Chaill Lim and Donald J. Huber
Katsumi Suzuki, Tadashi Tsukaguchi, Hiroyuki Takeda and Yoshinobu Egawa
Pod yield of `Kentucky Wonder' green bean (Phaseolus vulgaris L.) decreased at high temperatures due to a reduction of pod set. A highly positive correlation was observed between pod set and pollen stainability in flowers that were affected by heat stress about 10 days before anthesis. Pollen stainability was decreased by heat stress applied 8 to 11 days before flowering under controlled environment conditions. When mean air temperature during this period exceeded 28 °C, pollen stainability decreased under field conditions. Low pollen stainability indicated sensitivity to high temperatures about 10 days before flowering. A heat-tolerant cultivar showed higher pollen stainability than did heat-sensitive cultivars under high temperatures. These results demonstrated that heat tolerance at an early reproductive stage could be evaluated by analyzing pollen stainability using flowers developed under high temperatures.
M.S.S. Rao, Ajmer S. Bhagsari and Ali I. Mohamed
In Asian countries and among the oriental populations in the United States, vegetable soybeans are consumed much the same way as green peas are consumed. A need exists for developing soybean cultivars adapted to the U.S. environments to take advantage of the economic potential of vegetable soybeans for both domestic and international markets. During 1997, 12 vegetable soybean genotypes of exotic origin and two local U.S. soybean cultivars were evaluated for their agronomic performance in a randomized complete block, with four replications, at the Agric. Res. Stn. FVSU, Ga. At the R6 stage (when the seeds are of full size and still immature), plants from a half-meter-row length were sampled from each plot to estimate green pod and seed yield, and determine the nutritional quality of green beans. Significant differences were observed among genotypes for the agronomic and biochemical parameters studied. The green seed yield ranged from 7.1 (cv. Ware) to 14.0 Mg·ha–1 (cv. Tanbagura). Three cultivars, Tomahamare, Mian Yan, and Tousan-122, produced green seed yields in excess of 12 Mg·ha–1. The number of green pods varied between 1518 (Tanbagura) and 3526/m2 (cv. Hutcheson). The green bean oil and protein contents, ranged from 53.1 to 105.4 and from 354.2 and 418.3 g·kg–1, respectively. Thus, the green seeds contained only 30% of oil, but 50% to 80% of protein normally found in mature soybean seed. The glucose content was between 4.1% and 7.0%, while the phytate content varied between 0.93% and 1.3%. T he green seed yield was significantly correlated with number of green pods, number of green seeds, and green pod weight. This study showed that some exotic vegetable soybean genotypes may be suitable for production in the southeastern U.S.
Feishi Luan and Zhanyong Sun
The purpose of this study was to analyze the genetic relationship by using morphological, biochemical, and molecular markers. Sixty accessions of green bean [Phaseolusvulgaris (L.)], including 43 from North China, 13 from the International Center for Tropic Agriculture, and four from Poland, were collected and divided into three groups: cultivated determinate (35), cultivated indeterminate (12), and semi-wild determinate (13). Dendrograms were constructed based on the genetic similarity and distance analysis of these 60 accessions by using biological characters, allozyme, and random amplified polymorphic DNA (RAPD) markers. The 60 accessions were classified into two groups based on the genetic relationship examined in their biological characters. The cultivated indeterminate formed one group, and cultivated determinate and semi-wild determinate belonged to another group. Ten allozymes with 25 polymorphic loci divided the 60 accessions into nine groups, i.e., five groups for cultivated determinate, two groups for cultivated indeterminate, and two groups for semi-wild determinate. Twenty-nine RAPD markers with 314 polymorphic loci divided the 60 accessions into 13 groups, i.e., nine groups for cultivated determinate, three groups for cultivated indeterminate, and one group for semi-wild determinate. The average genetic similarities and genetic distance of intra-group and inter-groups were 0.81 and 0.75, and 0.19 and 0.24, respectively. Ten bands were characterized as specifically associated with cultivated determinate, one band specific for cultivated indeterminate, and one band for semi-wild. These biochemical and molecular markers provided more information than morphological markers. Allozyme and RAPD markers can be used as an available tool to exploit green bean germplasm in the future.
Charles A. Mullins, R. Allen Straw, J. Rennie Stavely and Jim Wyatt
`White Half Runner' is a popular green bean (Phaseolus vulgaris L.) cultivar in the southern Appalachian region of the United States. The cultivar is highly susceptible to rust and virus diseases. Nine breeding lines with `White Half Runner' parentage were compared to `White Half Runner' for rust tolerance, yield, and pod quality in 1998 and 1999 field trials at Crossville, Tenn. The BelTenn selections were developed by USDA plant breeders and the UT selections were developed by University of Tennessee plant breeders. Selections `BelTenn-RR-2', `BelTenn 4-12028', `BelTenn 4-12046', `BelTenn 4-12053', `BelTenn 5-2717' and `UT-96-3' were resistant to rust. Only `UT 96-4' had lower yields than `White Half Runner' in 1999. The BelTenn lines had slightly smaller pods, and the UT selections had larger and rougher pods than `White Half Runner'. `BelTenn-RR-2' wasreleased in 1995 as a breeding line with rust resistance and pod quality similar to `White Half Runner'. Further selection of BelTenn-RR-2 by a private seed company led to the naming of a cultivar named `Volunteer White Half Runner'.
Ebrahim M. Khah, Konstantinos A. Akoumianakis and Harold C. Passam
As good quality irrigation water becomes increasingly scarce in the Mediterranean region, especially in coastal areas where greenhouses are located, methods of economizing water consumption are essential. Therefore, the effect of the duration of irrigation on the quality and yield of seed of two cultivars of dwarf green bean (`Larma' and `Montano', Phaseolus vulgaris L.) was studied during fall and spring in Greece. Seeds were sown on 11 Sept. 2000 (fall crop) and 23 Feb. 2001 (spring crop) in peat compost and when the plants had two expanded leaves (11 and 20 days after sowing, respectively), they were transplanted to the soil of an unheated, plastic-covered greenhouse. The following irrigation treatments were applied: 1) irrigation for the entire duration (control), 2) irrigation until the first pods were dry, 3) irrigation until ≈50% of the pods had filled, and 4) irrigation till flowering. Fall cultivation was not suitable for seed production due to low yield and reduced seed quality. By contrast, the spring crop had a higher yield, seed size and good germination. Stopping irrigation of the spring crop at the drying of the first pods achieved an ≈20% saving in water without significantly affecting seed yield or quality. Earlier discontinuation of irrigation to achieve greater savings of water caused a reduction in yield, but did not affect seed quality.
James R. Baggett, Deborah Kean, Brian Yorgey, Diane Barrett and G.W. Varseveld
L. Soegiarto and R.B.H. Wills
Broccoli (Brassica oleracea), green bean (Phaseolus vulgaris), and bok choy (Brassica chinensis) were fumigated with nitric oxide (NO) gas in air or in nitrogen for 2 hours at 20
°C (68.0 °F), then stored at 20 °C in humidified air containing 0.1 μL.L-1 (ppm) ethylene. The postharvest life of all vegetables was extended by NO although the concentration of NO required and the magnitude of the extension varied between produce ranging from 14% for green bean to more than 50% for broccoli. NO uptake by produce from air was not significantly different than from nitrogen at the lower effective NO concentrations, but NO uptake was less from air at the highest concentration used for broccoli. Application of NO in an air atmosphere is considered a feasible, more convenient treatment regime for horticultural produce than use of a nitrogen atmosphere.