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Taifeng Zhang, Jiajun Liu, Shi Liu, Zhuo Ding, Feishi Luan, and Peng Gao

’, respectively ( Knavel, 1988 , 1990 ; Paris et al., 1984 ). Furthermore, Hwang et al. (2014) identified the dwarf gene mdw1 of the melon ‘PNU-WT1’ dwarf mutant on chromosome 7, which is highly homologous with CKX . Bulked-segregant analysis (BSA) is an

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S.O. Park, J.M. Bokosi, and D.P. Coyne

Plant growth habit is an important trait. Our objective was to identify RAPD markers linked to major gene for indeterminate growth habit using bulked segregant analysis in an F2 population from a bean cross Chichara (indeterminate growth habit × PC-50 (determinate growth habit). A total of 132 RAPD primers (600 RAPD primer screened) showed polymorphisms between bulked DNA derived from indeterminate and determinate plants. All markers showed coupling linkage with indeterminate growth habit. RAPD markers of A-8, A-17, C-7, C-15, D-4, D-5, F-6, F-16, G-9, H-3, H-20, and I-7 were 2.2 cM distant from the gene for indeterminate growth habit. Markers of B-7, B-16, B-17, C-8, E-1, F-1, F-20 and H-l9 primers were 4.6 cM distant from the gene for indeterminate growth habit.

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Zhoo-Hyeon Kim*

On the process of plant breeding, SSD(single seed descendant) method and bulk method are sometimes considered as they need no selections till being done active selection. It should be tested it was right or not. One F2 population was used for 8 years—selection based on two ways of selection: one was selected only on fruit characteristics without considering any other characters, the other was selected with considering several for agricultural aspects, even though on only visual observations. Nineteen lines were selected: fifteen lines from the latter, four lines from the former; and grown under four different environments for evaluation, which method is better, and which line is best. The characters related to plant status (plant height, leaf) and fruit characteristics were recorded. For the selection of the best lines, three methods were applied: Anderson's Metroglyph Analysis method (1957), Finlay and Wilkinson's Adaptation Analysis method (1963), Grafius's Geometrical Interpretation method (1956). Different three groups of best lines were formed by the three methods, independently. But the best few lines were always included in the three best groups. Among the best few lines, all of four lines from all round selection were always included, but only very few lines from selecting based on only fruit characters. It means that all round selection is more successful. Therefore, even though the selection method is SSD or Bulk method, it seems to be more reasonable to be selected lines based on observation on as many characters as possible, at same times with more lines, even if without any measuring, only with visual observation. If wanting only to progress generations without any selection, while hope to get available population, one should bred much more lines.

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Ahmed A. Tawfik and Jiwan P. Palta

We have shown that tuber calcium can be enhanced by supplying soluble forms of calcium near the tuber stolon region during bulking. In the present study we applied calcium nitrate or N-HIB during bulking (hilling, 3 and 6 wks after hilling) by injecting these Ca sources into sprinkler irrigation line. Field plots were established with cv `Russet Burbank' in sandy loam soil containing about 1200 Kg Ca ha-1. All plots received equal amounts of nitrogen. Plots receiving only nitrogen (as NH4NO3) at the same time served as split N controls and the plots receiving complete nitrogen by the time of hilling (non-split N) served as the grower control.

In 1990 compared to non-split-N control a consistently higher tuber yield was obtained with split-N, N-HIB (113 Kg.Ca ha-1) calcium nitrate (113 Kg Ca ha-1). However, these differences were not significant. Tuber calcium contents were increased with N-HIB and calcium nitrate. After 5 months of storage the incidence of soft rot and of internal brown spot was significantly reduced. In 1991 N-HIB (113 Kg ha-1) gave significantly higher tuber yield than other treatments. Tuber calcium contents were increased with both calcium nitrate and N-HIB treatments. After four months of storage incidence of internal brown spot was reduced by calcium nitrate and N-HIB although calcium nitrate was most effective. These results demonstrate that it is possible to improve tuber calcium contents by application of 113-226 Kg Ca ha-1 during bulking even in a soil containing sufficient calcium for plant growth.

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S.O. Park, A. Dursun, D.P. Coyne, and G. Jung

Common bacterial blight (CBB), incited by Xanthomonas campestris pv. phaseoli (Xcp), an important disease in common bean (Phaseolus vulgaris L.) Tepary bean (P. acutifolius A. Gray) is of interest to bean breeders because of resistance to CBB. Our objective was to identify RAPD markers linked to major genes for CBB resistance using bulked segregant analysis in an F2 population from a tepary bean cross CIAT640005 (R) X Nebr#4B (S). A total of 57 RAPD primers (602 RAPD primers screened) showed polymorphisms between bulked DNA derived from R and S CBB plants. All markers showed coupling linkage with CBB resistance. A good fit to a 3:1 ratio of bands for presence and absence using 11 RAPD primers was observed in 77 F2 plants. Markers of U-15 and L-7 primers were 2.4 cM distant from the gene for resistance to Xcp strain LB-2. RAPD markers of U-10, U-20, S-12, Y-4, F-13, P-6, Q-1, and Q-ll primers were 2.4 cM distant from the gene for resistance to Xcp strain SC-4A. RAPD markers of IJ-15 and L-7 primers were 8.4 cM distant from the gene for resistance to Xcp strain EKl l. The tepary RAPD linkage group includes three molecular markers and three genes for resistance to Xcp strains EK-l l, LB-2, and SC-4A and spans a length of 19.2 cM. This data supports the presence of Xcp races.

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William L. Bauerle* and Joe E. Toler

A multiplicative model of stomatal conductance was developed and tested in two functionally distinct ecotypes of Acer rubrum L. (red maple). The model overcomes the main limitation of the commonly used Ball-Berry model by accounting for stomatal behavior under soil drying conditions. It combined the Ball-Berry model with an integrated expression of abscisic acid-based control mechanisms (gfac). The factor gfac = exp(-β[ABA]L) incorporated the stomatal response to abscisic acid (ABA) concentration in the bulk leaf tissue [ABA]L into the Ball-Berry model by down-regulating the slope and coupled physiological changes at the leaf level with those of the root. The stomatal conductance (gs) down regulation is pertinent in situations where soil drying may modify the delivery of chemical signals to leaf stomates. Model testing results indicated that the multiplicative model was capable of predicting stomatal conductance under wide ranges of soil and atmospheric conditions in a woody perennial. Concordance correlation coefficients (rc) were high (between 0.59 and 0.94) for the tested ecotypes under three different environmental conditions (aerial, distal, and minimal stress). The study supported the use of the gfac factor as a gas exchange function that controlled water stress effects on gs and aided in the prediction of gs responses.

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Christopher Gunter, Senay Ozgen, Bjorn Karlsson, and Jiwan Palta

An increase in calcium concentration of potato tuber tissue has been shown to reduce soft rot severity and the incidence of internal physiological defects. Higher tuber calcium also seems to increase sprout vigor and maintain apical dominance by reducing subapical necrosis and sprout tip death. Preemergent applications of calcium at a rate of 0 and 26.5 kg·ha–1 from ammonium nitrate (PreAmNit), ammonium nitrate plus calcium nitrate (PreCaN), or calcium chloride plus calcium nitrate plus urea (PreCUC). A group of post-emergent split calcium nitrate plus calcium chloride plus urea (PostCUC) applications beginning with hilling and proceeding at 3, 6, and 8 weeks after hilling were also made at a rate of 56 kg·ha–1 calcium at each application time. From visual ratings of stand quality taken 64 days after hilling, we found plants receiving a preemergent application of nutrients or PostCUC had higher stand ratings than paired control plots. Internal tuber quality ratings revealed less internal brown spot in the PostCUC application in 168–364-g tubers. Yield of 112–168-g tubers was greatest from plants treated with PreCaN or PreCUC followed by PostCUC. PreAmNit plots had higher culls than the PreCUC plots. The non-split ammonium nitrate control (all nitrogen by hilling) produced a higher number of B-sized tubers than the PostCUC treatment. Also the PreAmNit+PostCUC had more B-sized tubers than PreCaN+PostCUC. In general the PostCUC treatment produced fewer small tubers and more large tubers than other treatments. These results suggest application of a small amount of calcium prior to emergence but after the sprouts have begun to develop improves seed performance. Furthermore these data show that supplemental calcium application during the season may improve tuber grade.

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Wallace Pill and Bing Shi

Kenaf stems were ground and sieved to yield fine (<2mm), medium (2 to 6 mm) or coarse (6 to 12 mm) grades. These grades were mixed at 25, 50 or 75% volumes in sphagnum peatmoss and then provided standard basal fertilization. Tomato and impatiens shoot fresh weights 4 weeks after transplanting (50 mg N.liter-1 daily liquid feed) were greatest in 25% medium kenaf, being 68 and 89%, respectively, those in peat-lite (ProMix BX). In a further study, medium kenaf was soaked for 3 days in 5000, 10000 or 15000 mg N.liter-1 from 20N-4. 3P-8.6K then mixed at 25% volume in peatmoss. Tomato seedlings transplanted into these media were provided 0, 100, 300 or 500 mg N.liter-1 daily liquid feed (LF) from 20N-4.3P-8.6K. With ≥100 mg N.liter-1 LF, soak solution concentration had no effect on shoot fresh weight. With 0 mg N.liter-1 LF however, kenaf media soaked in 10000 or 15000 mg N.liter-1 yielded greater shoot fresh weights than ProMix with 100 mg N.liter-1, LF.

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Catherine M. Whitman and Erik S. Runkle

and White’ were received 7 Jan. 2003. Seedlings were ≈9 weeks old when received and had average node counts of four or five for ‘Origami Blue and White’ and three to five for ‘Winky Double Red and White’. In this study, we define bulking as a period

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Eugene K. Blythe and Donald J. Merhaut

The physical properties of container-growing substrates, particularly air space, container capacity, and bulk density, have a significant impact on plant growth, and knowledge of these properties is essential in properly managing nursery