April - June 2007 - Kasetsart University

More documents

Recommendations

Info

Kasetsart J. (Nat. Sci.) 41 : 242 - 250 (2007) Composite Line Method for the Development of Early Generation Hybrids of Maize (Zea mays L.) Nguyen Phuong, Krisda Samphantharak* and Vatcharee Lertmongkol ABSTRACT Six commercial single crosses were used for the improvement of composite and inbred lines. Modified S 1-full sib selection was applied to improve the three sister line composite. Lines were visually selected under low-competition environment in honeycomb arrangement with equilateral triangular side of 0.866 m. Testcross as well as diallel cross were applied to identify high combining lines. All yield trials were conducted in randomized completed block design with 4 replications, 1 row plot of 5 m long and 0.75 × 0.25 m plant spacing. Standard cultural practices were regulated and irrigation was applied as needed. Statistically, there was no clear advantage of yield between composite and inbred lines in early generation testcrosses. Besides, the diallel sets of both groups of lines gave similar results. However, the top hybrids of overall trials came from composite crosses even though it was not significant. In addition, composite lines were superior to S 3 lines in yield, earliness and plant height. Modified S 1-full sib selection is a flexible breeding method but its merit for the construction of early generation hybrids must be thoroughly investigated even though the positive results were observed. Key words: maize breeding, testcross, honeycomb, composite line INTRODUCTION Development of single cross hybrid of maize is the ultimate goal of most of maize breeding programs. However, finding stable high yield inbred lines to ensure the high level of economic return for commercial hybrid seed production is the main obstacle of small and new emerged single cross development programs. Combined line selection and testing for combining ability is time and space consuming processes. Instead of five or six generations of selfing usually practiced in the development of inbred lines, composite-sibbing lines from individual of S 1 progenies have been proposed (Kinman, 1952). The method fixed the composite-sibbed lines since the first selfing and therefore improvement in the combining ability or other characteristics of composite-sibbing lines can not be made after several generations of mass sibbing unless effective selection is practiced. In other way, line selection from cross between closely related parents has been proved to be an effective method for inbred line development (Rasmusson and Phillips, 1977; Troyer, 1999). Selection for high and low yield lines effectively separated lines into high and low combining ability groups but yield of lines within group cannot be used as criterion Department of Agronomy, Faculty of Agriculture, Kasetsart university, Bangkok 10900, Thailand. * Corresponding author, e-mail: agrkrs@ku.ac.th Received date : 10/04/06 Accepted date : 04/09/06
for combining ability of lines (Lamkey and Hallauer, 1986). In addition, for effective differentiation of lines, Fasoula and Fasoula (1997) proposed line selection under nil-competition environment in honeycomb designs. In order to improve yield and combining ability of population, Landi and Frascaroli (1993) applied full-sib selection in F 2 population of single cross. The method proved to be very effective for several cycles of selection. However, the previous study of Genter (1976) which applied the same method suggested that using S 1 instead of S 0 to form fullsibs was more effective to identify high yielding full-sibs as well as in improvement of population per se. This finding agreed well with suggestion of Lonnquist (1950) that testing for combining ability after one generation of selfing is desirable when the composite sib-breeding method is used. The above finding suggested that alternate selfing and full sibbing among few closely related lines under low-competition environment should lead to uniform, high yield and high combining composite lines as high level of homozygosity is approached and provide a chance for continuous improvement of composite lines in the successive cycles. The present study therefore aim to formulate the effective breeding method for the development of composite lines and evaluate its merit as compared to the conventional line selection with early generation testing for combining ability. The modified S 1-full sib selection within related lines is proposed. MATERIALS AND METHODS Six commercial single cross hybrids comprised Monsanto 949, Monsanto 919, Pioneer A33, Pioneer 3012, Pacific 984 and Syngenta NK 48 were planted in normal plant spacing (0.75 × 0.25m) and selfed to obtain S 1 ears. Nine S 1 ears within each family were randomly grouped in to 3 ear sets, 3 sets per family and therefore resulted Kasetsart J. (Nat. Sci.) 41(2) 243 in 18 sets of 3 S 1 and 54 individual S 1 lines. They were separately ear-rowed in honeycomb arrangement (HC) with equilateral triangular side of 0.866m. Three best S 1 plants within each set were intercrossed (full sibbing) to form 18 intraset diallel crosses which will be refered to as full sib sets while 3 best S 1 plants from each family were also selfed to obtain 18 S 2 lines. Consequently, they were ear-rowed in HC, the 18 S 2 plants were selfed as well as testcrossed to the inbred tester, KRi 208 to obtain 18 S 3 lines and 18 testcrosses, S 2 × KRi 208 hybrids. The best S 2 lines by visual selection, one from each family, were also intercrossed to form 15 diallel crosses of 6 S 2. In the meantime, the best 3 F 1 plants from each full sib set were crossed in all possible combinations to form 18 composite lines and they will be referred to as composite line cycle-1 (C#1). The method is essentially similar to S 1 and full-sib selection of which it will be referred to as modified S 1-full sib selection for composite line development. Afterward, C#1 were testcrossed to KRi 208. As a result, 18 C#1 testcrosses were obtained. In addition, the best C#1 by visual selection, one from each family, were intercrossed to form 15 diallel crosses of 6 C#1. Yield trials of 18 S 3 lines, 18 C#1, 18 testcrosses of S 2 × KRi 208, 18 testcrosses of C#1 × KRi 208, 15 diallel crosses of 6 C#1 and 15 diallel crosses of 6 S 2 lines were conducted in separate trials in adjacent areas in randomized completed block design with 4 replications, 1 row plot of 5m long and 0.75 × 0.25m plant spacing. Five original hybrids were included as common checks in all hybrid yield trials. Pacific 984 was excluded and replaced by Suwan 4452 because the former was dropped out from the market and there was no seed available. All experiments were conducted from September 2004 to March 2006 at National Corn and Sorghum Research Center, Suwan Farm, in Nakhon Ratchasima province (14 0 30’N, 101 0 30’ E, and 356m asl.), Thailand under standard cultural
Page 1 and 2: April - June 2007 Volume 41 Number
Page 3 and 4: KASETSART JOURNAL NATURAL SCIENCE T
Page 5 and 6: Kasetsart J. (Nat. Sci.) 41 : 205 -
Page 7 and 8: harvesting time which started from
Page 9 and 10: y Chen and Paull (2000). Figure 1 a
Page 11 and 12: pineapple fruit allowed the accumul
Page 15 and 16: Kasetsart J. (Nat. Sci.) 41(2) 215
Page 17 and 18: Cluster analysis Cluster analysis u
Page 21 and 22: Table 3 (Continued) 1 2 3 4 5 6 7 8
Page 25 and 26: CONCLUSION AFLP markers classified
Page 29 and 30: difference of soil texture used in
Page 31 and 32: under wet soil condition planting.
Page 33 and 34: tropics. Following the expansion, w
Page 35 and 36: sealed in a plastic box with 1 cm w
Page 37 and 38: moisture content increment after so
Page 39 and 40: Frequency Frequency 30 20 10 0 20.0
Page 41: School, Kasetsart University. The a
Page 45 and 46: selective mass sibbing within indiv
Page 47 and 48: Although most of S 2-interfamily hy
Page 49 and 50: composite sets as used in this stud
Page 53 and 54: days. The numbers of calli producin
Page 55 and 56: the report of Ching (1982) showing
Page 57 and 58: clearly amplified bands generated b
Page 59 and 60: caused by either the recombination
Page 61 and 62: Kuhlmann, V. and B. Foroughi-Wehr.
Page 63 and 64: Xanthomonas fuscans subsp. aurantif
Page 67 and 68: was collected and washed with 70% e
Page 69 and 70: expected size was amplified with 35
Page 71 and 72: eaction technique has been used for
Page 73 and 74: Schaad, N.W., D. Opgenorth and P. G
Page 75 and 76: MATERIALS AND METHODS Model descrip
Page 79 and 80: calculated TF value calculated TF v
Page 81 and 82: sincere gratitude and deep apprecia
Page 83 and 84: 1989). In monogastrics, the inclusi
Page 85 and 86: of all LLS samples in this study we
Page 87 and 88: Melbourne, Parkville, Victoria. Goe
Page 89 and 90: considered responsible for low prod
Page 93 and 94:
mineral supplementation suggested b
Page 95 and 96:
Body weight chane (kg/head) 32 30 2
Page 97 and 98:
CONCLUSION AND RECOMMENDATION With
Page 99 and 100:
SAS. (Statistical Analysis System).
Page 101 and 102:
genes covering a variety of desirab
Page 103 and 104:
mg/l NAA and 0.5 mg/l zeatin) incub
Page 105 and 106:
5. Purification by various sucrose
Page 107 and 108:
as the culture period increased. So
Page 109 and 110:
culture, pp. 1-20. In L.C. Fowke an
Page 111 and 112:
Kasetsart J. (Nat. Sci.) 41 : 311 -
Page 113 and 114:
GC. Analytical methods Total carboh
Page 115 and 116:
ash. The crude hot water polysaccha
Page 117 and 118:
spirulan (H-SP), and a desulfated c
Page 119 and 120:
Page 121 and 122:
cells often displayed an increased
Page 123 and 124:
LITERATURE CITED Bell, T.A. and D.V
Page 125 and 126:
for alternative sources of supply.
Page 127 and 128:
BR2.1.2 formed the same clade with
Page 129 and 130:
supplement with glutamate (Iida et
Page 131 and 132:
optimal for S. limacinum BR2.1.2 fo
Page 133 and 134:
fluorescent lamp at 1.5 kLux develo
Page 135 and 136:
Page 137 and 138:
Wisconsin, USA). Total extracted RN
Page 139 and 140:
RESULTS Cloning and sequencing of m
Page 141 and 142:
Expression of rmIL-2 and purificati
Page 143 and 144:
other strains of mice have differen
Page 145 and 146:
dose interleukin-2 therapy promotes
Page 147 and 148:
The chitosano-oligosaccharides are
Page 149 and 150:
enzyme and cells were maximized by
Page 151 and 152:
of crude chitosanases. Fortunately,
Page 153 and 154:
Relative activity (%) 100 80 60 40
Page 155 and 156:
Uchida, K. Tateishi, O. Shida and K
Page 157 and 158:
MATERIALS AND METHODS 1. Materials
Page 159 and 160:
without coating and coated with pec
Page 161 and 162:
in Table 5-7. It was found that the
Page 163 and 164:
Page 165 and 166:
the cultures at 10,200 × g for 15
Page 167 and 168:
incubation and reached the final pH
Page 169 and 170:
y lysine- and tyrosine-decarboxylas
Page 171 and 172:
during the stages of ripening as su
Page 173 and 174:
Page 175 and 176:
As the 25 companies were divided in
Page 177 and 178:
All the data comes up with informat
Page 179 and 180:
as piece “A” or straight as pie
Page 181 and 182:
et al. (1998); Zeng (2000); and Tal
Page 183 and 184:
p 1, i * Kasetsart J. (Nat. Sci.) 4
Page 185 and 186:
c ≤ c2 jq2 j n q p k p * 2, j , ,
Page 187 and 188:
algorithm would consider RM 5, prio
Page 189 and 190:
Kasetsart J. (Nat. Sci.) 41(2) 389
Page 191 and 192:
the maximum deviation of about 10%.
Page 193 and 194:
Stock Quantities Using Heuristic Op
Page 195 and 196:
which dynamically and automatically
Page 197 and 198:
2. Framework architecture and compo
Page 199 and 200:
Risk (VaR) calculation which was im
Page 201 and 202:
Throughput (job/sec) 7 6 5 4 3 2 1
Page 203 and 204:
Speed up 40 35 30 25 20 15 10 5 0 F
Page 205 and 206:
and discovery, resource selection a
show all

April - June 2007 - Kasetsart University

Create successful ePaper yourself

Delete template?

Save as template?