Citrullus lanatus (Thunb.) Matsum. & Nakai - Cucurbit Breeding ...

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We performed BSA for the polymorphic markers. For each cross, we used two bulks (one resistant and one susceptible) of DNA of F 2 plants. The bulks from the cross PI 189225 × 'NH Midget' had DNA from seven resistant or four susceptible plants, respectively. The bulks from the cross PI 482283 × 'NH Midget' had DNA from eight resistant or eight susceptible plants, respectively. Following BSA, we mapped the polymorphic markers from BSA on the F 2 populations. Genotypic data were tested for linkage to phenotypic values using Mapmaker 2.0 for Macintosh, adopting the Kosambi mapping function. In our experiment, some families had most of the single-plant ratings close to the mean of the rating scale (4 to 6). This could have led to a misclassification of the F 2 genotypic value and we controlled for this effect by excluding those families from the linkage analysis. Finally, one RAPD marker was found to be possibly linked to resistance to gummy stem blight from PI 189225. To verify the consistency of this marker among other resistant PI accessions, we tested this marker among resistant and susceptible PI accessions and cultivars of diverse geographical origin and level of resistance (Gusmini et al., 2005b). We used 37 resistant PI accessions (PI 189225, PI 195771, PI 211915, PI 227203, PI 244019, PI 247398, PI 249009, PI 271982, PI 274035, PI 277979, PI 296332, PI 357677, PI 482257, PI 482260, PI 482283, PI 482293, PI 482294, PI 482297, PI 482307, PI 482315, PI 482326, PI 482342, PI 482343, PI 482357, PI 482374, PI 482379, PI 490375, PI 490376, PI 490384, PI 500312, PI 500323, PI 508443, PI 512361, PI 512388, PI 512398, PI 526233, and PI 542123), and 42 susceptible PI accessions (PI 113326, PI 167124, PI 169237, PI 169285, PI 169286 , PI 171581, PI 173669, PI 173888, PI 175662, PI 175665, PI 176495, PI 176916, PI 177320, PI 179885, PI 179886, PI 183398 , PI 207472, PI 214044, PI 222775, PI 223764 , PI 226445 , PI 226445, PI 226459, PI 234287, PI 266028, PI 277991, PI 357660, PI 357689, PI 357735, PI 357741, PI 368510, PI 381734, PI 435282, PI 512373, PI 512399, PI 525084 , PI 525086, PI 525087, PI 525091, PI 536460, PI 537465, PI 595203). In addition, we included a set of four susceptible cultivars ('Allsweet', 'Charleston Gray', 'Congo', and 'NH Midget'). Results and Discussion The DNA extraction protocol developed during our experiments allowed us to obtain DNA suited for PCR screening with SSR, ISSR, and RAPD primers. The average absorbance ratios 260/230 139
(DNA/Polysaccharides) and 260/280 (DNA/Proteins) for 20 random samples measured 1.75 (optimum = 1.8±0.2) and 2.1 (optimum ≥2.0), respectively. Thus, the quality of the DNA was considered good and consistent across samples (Fig. 1). Nevertheless, the complete protocol suggested by Levi and Thomas (1999) should be considered the most appropriate for the extraction of large quantities of high quality DNA from watermelon leaves. Our modified procedure should be adopted for faster extraction of small quantities of DNA from a large number of samples. Furthermore, the full procedure by Levi and Thomas would be more appropriate for studies of molecular markers requiring highly purified DNA (i.e., AFLP and RFLP markers). Of the 355 primers tested (Table 1), 30% did not produce any PCR amplification product. Thus, 248 primers produced bands that could be compared in order to identify polymorphism among the parental lines of our populations segregating for resistance to gummy stem blight. The most efficient primers in producing positive PCR amplifications were those designed for ISSR markers (100%), followed by EST-based markers (81%), RAPD markers (68%), and SSR markers (64%). However, RAPD primers yielded the highest number of polymorphic marker bands (97%), followed by ISSR primers (60%), SSR primers (48%), and EST-based primers (20%). The RAPD markers were all dominant, as expected. The codominant:dominant marker ratio was 1.25 for ISSR, 0.57 for EST-based, and 2.00 for SSR primers. In summary, all the marker types that we used had medium to high efficiency in amplifying watermelon DNA from a C. lanatus var. lanatus cultivar and two C. lanatus var. citroides PI accessions. Primers often used for fingerprinting (RAPD and ISSR) were the most efficient in identifying polymorphism among parental lines. SSR primers had a medium efficiency in polymorphism detection, but allowed the identification of twice the number of codominant versus dominant markers. EST-based markers were mainly monomorphic in our experiments, so we discontinued their use. For future studies, we would use primarily SSR markers, due to their high efficiency in amplifying codominant polymorphic bands in our populations. Nevertheless, we would continue to use RAPD and ISSR markers as a fast and efficient means of identification of polymorphism. The analysis of variance for the phenotypic values of the F 3 plants showed that replication effects were non-significant, and most of the variation was due to the genotype of the families (Table 2). Thus, we pooled 140
Page 1 and 2:
Abstract GUSMINI, GABRIELE. Inherit
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Biography Gabriele Gusmini was born
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Currently, Gabriele is planning his
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Table of Contents LIST OF TABLES...
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Germplasm and Crosses..............
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GENERAL INTRODUCTION LIST OF TABLES
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GENERAL INTRODUCTION LIST OF FIGURE
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HERITABILITY AND GENETIC VARIANCE E
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Brief History of Watermelon Breedin
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absence of trichomes on the leaves
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The genetics of the flesh color in
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The primary nematode species attack
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1975), but no gene has been found f
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Henderson, W.R., G.H. Scott, and T.
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Shimotsuma, M. 1963. Cytogenetical
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Table 1. Watermelon cultivars with
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Figure 2. Cultivar Allsweet, releas
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Figure 4. Watermelon seeds size: 1
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Introduction The inheritance of rin
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stripes. In his study, Shimotsuma c
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Diamond'), GG mm = mottled dark gre
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Shimotsuma, M. 1963. Cytogenetical
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Figure 2. Cultivars Japan 6 and Chi
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Figure 4. Cultivars Crimson Sweet (
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Abstract The watermelon [Citrullus
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The rind (skin) colors and patterns
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two hybrids are the original canary
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Names and symbols for new genes pro
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Salmon Yellow and Red Flesh During
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During our experiments we did not f
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Poole, C.F. and P.C. Grimball. 1945
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Table 2. Single locus goodness-of-f
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Table 6. Continued. z Generation To
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Figure 1. Intermittent stripes in '
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Figure 3. Moons and stars induced o
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Figure 5. Examples of unexpected fl
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Abstract High yield is a major goal
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States appears to be narrow, with m
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y using only two replications from
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value=0.0001), indicating that cult
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Levi, A., C.E. Thomas, A.P. Keinath
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Table 1. Analysis of variance (degr
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Table 2. Continued. Yield z Fruit s
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Table 2. Continued. Yield z Fruit s
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w L/D = length/diameter ratio measu
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Abstract The cultivated watermelon
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dominance, and epistatic effects we
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thumped (Maynard, 2001). Weights we
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The giant-fruited parents had a lar
Page 103 and 104: Literature Cited Brar, J.S. and K.S
Page 105 and 106: Table 1. Phenotypic variances by ge
Page 107 and 108: Table 2. Variance and heritability
Page 109 and 110: t h 2 n = narrow-sense heritability
Page 111 and 112: Table 3. Continued. Effective Facto
Page 113 and 114: Figure 1. Each of the three cultiva
Page 115 and 116: CHAPTER FIVE HERITABILITY AND GENET
Page 117 and 118: fungus that is seed-borne (Lee et a
Page 119 and 120: the technique described herein. Pyc
Page 121 and 122: 9 = plant dead. Plants with a disea
Page 123 and 124: The possible gain from selection pe
Page 125 and 126: Based on our data, Norton may not h
Page 127 and 128: Gusmini, G., T.C. Wehner, and G.J.
Page 129 and 130: Sherbakoff, C.C. 1917. Some importa
Page 131 and 132: Table 1. Single locus goodness-of-f
Page 133 and 134: Table 1. Continued. z Generation To
Page 135 and 136: w Expected was the hypothesized seg
Page 137 and 138: on leaves only; 5 = some leaves dea
Page 139 and 140: on leaves only; 5 = some leaves dea
Page 141 and 142: z Data are ratings from four famili
Page 143 and 144: CHAPTER SIX PRELIMINARY STUDY OF MO
Page 145 and 146: fungus that is seed-borne (Lee et a
Page 147 and 148: approach was successful in assembli
Page 149 and 150: subculture on artificial medium bas
Page 151 and 152: We extracted DNA using an extractio
Page 153: products using the Genescan ® -500
Page 157 and 158: Future Research Based on our prelim
Page 159 and 160: Gusmini, G., T.L. Ellington, and T.
Page 161 and 162: Perin, C., L.S. Hagen, V. De Conto,
Page 163 and 164: Table 2. Analysis of variance for t
Page 165 and 166: 029 v 1 . 3 3 . . 3 4 3 3 . . . + B
Page 167 and 168: Table 3. Continued. 071 v 1 3 . 3 4
Page 169 and 170: Table 3. Continued. 113 2 4 5 5 4 3
Page 171 and 172: Table 3. Continued. 155 2 4 5 4 . 4
Page 177 and 178: Figure 1. Agarose gel electrophores
Page 179 and 180: 1 5 10 15 20 25 30 35 + + + + + + +
Page 181 and 182: The genetics of rind color (or patt
Page 183 and 184: were not successful, even though se
Page 185 and 186: Breeding Methods Traits of interest
Page 187 and 188: alternative to biotechnology and te
Page 189 and 190: The solution to these problems is n
Page 191 and 192: Cucurbit Gene List Committee. 1979.
Page 193 and 194: Henderson, W.R., G.H. Scott, and T.
Page 195 and 196: Matthews, P. (ed.). 1993. The guinn
Page 197 and 198: Provvidenti, R. 1991. Inheritance o
Page 199 and 200: Souza, F.F.d., M.A.d. Queiroz, and
Page 201: Wright, S. 1968. The genetics of qu
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