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

More documents

Recommendations

Info

have been contradictory (Gill and Kumar, 1988; Rajendran and Thamburaj, 1993; Sachan and Nath, 1976). Often, the experiments included only a small number (N max=10) of non-randomly chosen elite cultivars as parents, so the results are valid only for those specific crosses and are not generally applicable. Taken as a group, the studies indicate the presence of heterosis in watermelon and the importance of GCA in the choice of parents for hybrid production. Ferreira et al. (Ferreira et al., 2002) substantiated these conclusions testing seven intercrossing populations with evaluation of reciprocal crosses. There were significant GCA, SCA, and reciprocal combination effects, along with additive effects for all yield traits, except for the number of days to first female flower and number of seeds per fruit. A second study evaluated GCA and SCA for tetraploid females crossed with diploid males for the production of triploid seeds (Souza et al., 2002). This study confirmed a higher magnitude of GCA effects than SCA effects and strong additive effects for yield components, except for earliness and some qualitative indexes (i.e. hollowheart incidence). Today, watermelon breeders are less interested in studying heterotic effects and combining ability as reasons to prefer hybrids to inbreds for cultivar release. Hybrids have proven their advantage for protection of valuable parent lines. Furthermore, seedless cultivars are in high demand and can be produced only as triploid hybrids. However, in the future it might be possible to develop transgenic diploid seedless watermelons. In that case, the question of the advantage in using heterotic hybrids vs. inbred cultivars will still be important. Overall, watermelon yield in the United States has been increasing during the last four years from 24 Mg ha -1 in 1998 to 29 Mg ha -1 in 2002 (USDA-ARS, 2003). Part of the increase in yield might be due to more reliable production practices and to the availability of more effective pesticides (Maynard, 2001). The impact of environmental factors such as irrigation or general water availability on yield was important in contrasting inbred cultivars vs. hybrids in Florida in 1985. The hybrids outyielded inbred cultivars only in irrigated fields, while in dry conditions yield was the same for both groups, although fruit quality was higher among the inbred cultivars (Rhodes, 1985). Many watermelon yield trials are run each year in the United States and few differences among the experimental entries in the trial are usually observed. Our question was whether that was due to a lack of genetic variation for yield in the crop species, or a lack of genetic variation for yield among the new experimental entries being tested. Genetic diversity among currently grown watermelon cultivars in the United 63
States appears to be narrow, with many derived from 'Allsweet'. Therefore, a diverse set of obsolete inbred cultivars that do not trace to 'Allsweet' and that represents as wide an array of cultivars as possible, were included in this study. The objective of this study was to measure yield in a diverse set of watermelon cultivars. In addition, we were interested in identifying high yielding cultivars for use in breeding programs. Materials and Methods The experiment was conducted at the Horticultural Crops Research Station at Clinton, North Carolina (2001 and 2002) and at the Cunningham Research Station at Kinston, North Carolina (2002). The experiment at Clinton was a randomized complete block with four replications, 80 cultivars, and two years. At Kinston the experiment had two replications and 80 cultivars. All 80 cultivars were evaluated for all traits, except 'Weeks NC Giant' which had a low emergence rate at Clinton in 2001. Field rows were direct seeded on raised, shaped beds on 3.1 m centers. Plots were 3.7 m long, with 0.6 m between hills, and 2.5 m alleys at each end of the plot. At Kinston, rows were covered with black polyethylene mulch and drip irrigated. The experiment was conducted using horticultural practices recommended to the growers by the North Carolina Extension Service (Sanders, 2001). Soil type at Clinton was an Orangeburg loamy sand (Fine-loamy, kaolinitic, thermic Typic Kandiudults). Soil type at Kinston was a Norfolk sandy loam (Fine-loamy, kaolinitic, thermic Typic Kandiudults). Field preparation at Clinton included the soil incorporation of a 10-8.3-4.4 (N-P-K) fertilizer applied at 561 kg ha-1. Fertilizer application for the remainder of the growing season consisted of 224 kg ha-1 of 13.5-0- 19.8 (N-P-K) and 112 kg ha-1 of calcium along with 15.5-0-0 (N-P-K). Kinston field preparation included soil incorporation of a 10-16.6-8.8 (N-P-K) fertilizer applied at 336 kg ha-1 and the fumigant Telone C-17 (1,3- Dichloropropene + chloropicrin) applied at a rate of 60 L ha-1. At transplanting, 20-16.6-8.8 (N-P-K) fertilizer was applied (less than 5.6 kg ha-1 or a water diluted equivalent of a 1-0.83-0.44 (N-P-K) fertilizer). The differences in cultural practices between the two locations reflected the two most common production systems adopted by watermelon growers, bare ground and overhead irrigation vs. black polyethylene mulch and drip irrigation. 64
Page 1 and 2:
Abstract GUSMINI, GABRIELE. Inherit
Page 3 and 4:
Biography Gabriele Gusmini was born
Page 5 and 6:
Currently, Gabriele is planning his
Page 7 and 8:
Table of Contents LIST OF TABLES...
Page 9 and 10:
Germplasm and Crosses..............
Page 11 and 12:
GENERAL INTRODUCTION LIST OF TABLES
Page 13 and 14:
GENERAL INTRODUCTION LIST OF FIGURE
Page 15 and 16:
HERITABILITY AND GENETIC VARIANCE E
Page 17 and 18:
Brief History of Watermelon Breedin
Page 19 and 20:
absence of trichomes on the leaves
Page 21 and 22:
The genetics of the flesh color in
Page 23 and 24:
The primary nematode species attack
Page 25 and 26:
1975), but no gene has been found f
Page 27 and 28: Henderson, W.R., G.H. Scott, and T.
Page 29 and 30: Shimotsuma, M. 1963. Cytogenetical
Page 31 and 32: Table 1. Watermelon cultivars with
Page 33 and 34: Figure 2. Cultivar Allsweet, releas
Page 35 and 36: Figure 4. Watermelon seeds size: 1
Page 37 and 38: Introduction The inheritance of rin
Page 39 and 40: stripes. In his study, Shimotsuma c
Page 41 and 42: Diamond'), GG mm = mottled dark gre
Page 43 and 44: Shimotsuma, M. 1963. Cytogenetical
Page 45 and 46: Figure 2. Cultivars Japan 6 and Chi
Page 47 and 48: Figure 4. Cultivars Crimson Sweet (
Page 49 and 50: Abstract The watermelon [Citrullus
Page 51 and 52: The rind (skin) colors and patterns
Page 53 and 54: two hybrids are the original canary
Page 55 and 56: Names and symbols for new genes pro
Page 57 and 58: Salmon Yellow and Red Flesh During
Page 59 and 60: During our experiments we did not f
Page 61 and 62: Poole, C.F. and P.C. Grimball. 1945
Page 63 and 64: Table 2. Single locus goodness-of-f
Page 69 and 70: Table 6. Continued. z Generation To
Page 71 and 72: Figure 1. Intermittent stripes in '
Page 73 and 74: Figure 3. Moons and stars induced o
Page 75 and 76: Figure 5. Examples of unexpected fl
Page 77: Abstract High yield is a major goal
Page 81 and 82: y using only two replications from
Page 83 and 84: value=0.0001), indicating that cult
Page 85 and 86: Levi, A., C.E. Thomas, A.P. Keinath
Page 87 and 88: Table 1. Analysis of variance (degr
Page 89 and 90: Table 2. Continued. Yield z Fruit s
Page 91 and 92: Table 2. Continued. Yield z Fruit s
Page 93 and 94: w L/D = length/diameter ratio measu
Page 95 and 96: Abstract The cultivated watermelon
Page 97 and 98: dominance, and epistatic effects we
Page 99 and 100: thumped (Maynard, 2001). Weights we
Page 101 and 102: 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 and 154:
products using the Genescan ® -500
Page 155 and 156:
(DNA/Polysaccharides) and 260/280 (
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 173 and 174:
Page 175 and 176:
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
show all

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

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?