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TOMATO.ENG
Improvement of Winter, Heat Tolerant and Long-Shelf Life Tomato
Maneechat Nikornpun, Jaturong Pongmanee and Supaporn Punrawong
ABSTRACT
Improvement of 3 heat tolerant tomato varieties; L22, 598 (CL5915-2-4-1-1) and 607 (CL5915-223-2-1-0) for long shelf life of fruit. Mutant genes nor1 and nor2 were used. Hybrid between the heat tolerant varieties and the mutant varieties were backcrossed to their recurrent varieties. Backcrossed progenies of the second and the third generations to variety L22 showed 4-9% higher yield and longer shelf life of fruit than variety L22. When fruits were kept at room temperature for 30 days, the 2nd and 3rd backcrossed progenies had 18-38% good fruits while variety L22 had none. Backcrossed progenies of the second and third generations to variety 598 showed 15-54% higher yield and longer shelf life of fruit than variety 598. The same results were obtained in the 2nd and 3 rd backcrossed progenies of variety 607. They showed 23% higher fruit yield and longer shelf life of fruit than variety 607.
Two heat tolerant varieties; 667 (CL5915-206 D4-2-5-0) and 669 (CL5915-223 D4-2-1-0) were crossed to heat tolerant and winter tomato varieties. They were selfed and selected for several generations for heat tolerant and good fruit qualities. Some selected varieties from crosses 502 x 669 and 574 x 667 showed higher yield than control varieties; Lima and VF134-1-2. The yields of the selected varieties were 69.16 and 66.16 t/ha while the control varieties were 58.51 and 49.88 t/ha, respectively. Fruit firmness of the selected varieties was as good as the control varieties.
Key words : heat tolerant, mutant genes and back crossed.
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Department of Agriculture, Chiang Mai University, Chiang Mai, Thailand 50200.
Winter tomato varieties were improved by using variety Lima as a male parent to cross to some recurrent winter tomato varieties; 413, 452, 499, 514 and 560. Progenies of the hybrids were selected by pedigree method. The inbred lines of the crosses showed 12-32% higher yield than control varieties; VF134-1-2 and Lima. The inbred line from crossed 452 x 351 showed the highest yield, 44.29 t/ha and while varieties Lima and VF134-1-2 showed 33.29 and 33.66 t/ha, respectively. Most of the inbred lines showed fruit firmness as good as the control varieties. Inbred line 499 x 351 yielded secondly to line 452 x 351, it yielded 43.34 t/ha. When it was used as a testing variety at Ban Maekung and Ban Hankaew around the outskirt of Chiang Mai, farmers adopted the line for production.
INTRODUCTION
Tomato has become an important vegetable for Thai people. Eventhough it was an introduced crop from Western world. Young generations of Thai consummed tomato more than older generations. Tomato is used both as fresh and processed products. Common products are tomato paste in canned fish, ketchup and juice.
Since most of tomato varieties are from Western world, they do not adapt well to our hot climate. Tomato yield in Thailand is very low. Besides, there are environmental problems such as pest and disease. High temperature reduced fruit setting and development. It also promotes tropical diseases such as bacterial wilt, caused by Ralstonia solanacearum, other diseases such as late blight caused by phytophthera infestan and leaf curled caused by virus.
Researchers from many institutions and private companies in Thailand have tried to develop heat tolerant tomato for almost 30 years. Well known tomato varieties used are Seeda, Seedathip, SVRDC4 and L22. The heat tolerant varaieties are able to set fruit and developed under hot climate. However, fruit quality is very poor because of low percentage of soluble solid and short-shelf life of fruit. They are not suitable for processing plants. The author had tried to develop other varieties from the genetic material of the Asian Vegetable Research and Development Center such as CL 9-0-01 and CL143-0-10-3. However, these varieties were not adopted. Additionally, the author tried to improve fruit quality of L22 variety by crossing with a good winter variety, VF134-1-2. The F1 hybrid variety showed more heat tolerant than VF134-1-2 and better fruit quality than L22 (Lumyong and Wivutvongvana, 1984; Nikornpun, 1994 and Pongmanee et al., 1994). The variety could be used for summer production. However, the hybrid seeds was not produced commercially for farmers.
Heat tolerance is only part of the problems in tomato produciton. Major diseases such as bacterial wilt and leaf curled virus always accompany with high temperature. Thai researchers have been tried very hard to find resistant variety for these diseases. However, the efforts are not yet successful.
In 1980, the author received a support from Dr. R.B. Singh, Food and Agriculture organization to develop tomato varieties and production technology. High yield and disease resistant variety of tomato were the target of the project which tried to improve yield. Many winter tomato varieties such as Farmer209, LimaVF, VF134-1-2, P502, Hypeel 235, Aragon F1, UC82VF, Peto95, Early peel1448, Peto94 and CL1591-5-0-5-1 were tested (Wivutvongvana. 1980). Fruit yield of these varieties were not significantly different. Post harvest quality and processing quality of these varieties (except CL1591-5-0-5-1) were more or less the same. The project last only one year but it was the initiation of many breeding programs of tomato such as winter tomato, heat tolerant tomato and long-shelf life tomato. These programs gave many outstanding tomato varieties with high yield, good processing quality and long-shelf life.
MATERIALS AND METHODS
Improvement of winter tomato for high yield and good fruit quality.
Winter tomato varieties were crossed, variety 351 – Lima was used as a male parent and varieties 413-367 Farmers 112, 452-Lima (RS 1301) VF, 499-UC 82 VF, 514-Cannery Row and 560-C x D 103 hybrids were used as female parents. Progenies of the crossed were selected for 4 generations by using a pedigree method. Lines 413 x 351, 452 x 351, 499 x 351, 514 x 351 and 560 x 351 were obtained after the selection. They were grown at Chiang Mai University in winter 1995. Randomized complete block design with 3 replications was used. At harvesting time, fruit yield, fruit weight and fruit firmness were recorded.
Improvement of heat tolerant tomato for good fruit quality.
Heat tolerant tomato varieties, 667 (CL 5915-206 D4-2-5-0) and 669 (CL 5915-223D4-2-1-0) from the Asian Vegetable Research and Development Center (AVRDC) were used as female parents and winter tomato varieties, 414-369 Farmers 209, 502-Peto-81, 562- C x D 105 hybrid, 567-N40-8-10B, 570- x 212-WD251B, 572 x 2974-WE220B, 574- x 3333-6-3-5B, 579-X3501 hybrid and 580-x3523 hybrid were used as male parents. One heat tolerant tomato variety, 54-CL 1591-5-0-1-7 was use as a male parent. Progenies of the crossed were selected for 4 generations by using a pedigree method. Lines 54 x 667, 414 x 667, 502 x 669, 562 x 667, 567 x 667, 570 x 667, 572 x 667, 574 x 667, 579 x 667 and 580 x 667 were obtained. They were tested in summer (February-May 1996) at Chiang Mai University. Randomized complete block design with 3 replications was used where varieties VF 134-1-2 and Lima were standard varieties. At harvesting time, fruit yield, fruit weight, fruit firmness, and fruit cavity were recorded.
Improvement of heat tolerant tomato for long-shelf life by genes nor 1 and nor 2 and bacterial wilt resistance.
Heat tolerant tomato varieties 598 (CL5915-214-1-1), 607 (CL5915-223-2-1-0) and L22 were used as female lines. They were crossed with variety nor 1 (from University of Missuri) and variety nor 2 (from Cornell University) which were used as male lines. F1 hybrids were backcrossed with the female varieties L22, 598 and 607. The F1 hybrids, backcrossed progenies of the first second and third generations were tested in summer (February-May 1993) at Chiang Mai University. At harvesting time fruit yield, fruit color, fruit firmness pH, soluble solid and total acid were recorded. Fruits were kept for 30 days at room temperature. Number of good fruits after 30 days of storage was recorded. Fruit firmness was measured by Metek which had 0.72 cm in diameter and 0.5 cm in depth. The firmness was recorded in kilogram per square centimeter. Fruit color was compared with standard color chart (Methuen Handbook of Colour, Korherup and Wanscher. 1978). Soluble solid was measured by a hand refractometer. Acidity was measured by titration for total acidity as percentage of citricacid with NaOH and phenolpthalein was used as an indicator.
Two bacterial wilt resistant varieties were obtained from Department of Agriculture. They were crossed with the third backcrossed populations of L22, 598 and 607. The F1 hybrid were screened for bacterial wilt resistance by using petiole innoculations. The experiment was in the process of screening.
RESULTS AND DISCUSSION
Winter tomato
Ten years after the FAO project, the author and colleague developed some winter tomato varieties, by using pedigree method. The developed varieties were pure inbred lines. They were tested by using randomized complete block design with 3 replications. They yielded 13-32 % higher than standard varieties VF 134-1-2 and Lima (Table 1 and Figure 1) (Pongmanee et al., 1994). Eventhough the differences in yields were not statistically significant but they showed the potential of high yields of the developed varieties. High yielding varieties were 452 x 351, 499 x 351 and 413 x 351 which yielded 44.29, 43.34 and 42.48 t/ha, respectively. Fruit firmness of these varieties was as firm as the standard ones.
Table 1Fruit yield and fruit firmness of winter tomato varieties (winter 1995).
Variety* / Fruit weight(g) / Yield
(t/ha) / % of yield vs
standard varieties / Fruit firmness** / Remark
413 x 351 / 85 / 42.48 / 127.0 / 1 / Developed line
452 x 351 / 82 / 44.29 / 132.0 / 1 / Developed line
499 x 351 / 83 / 43.34 / 129.5 / 1 / Developed line
514 x 351 / 57 / 37.77 / 112.8 / 1 / Developed line
560 x 351 / 80 / 38.14 / 113.9 / 2 / Developed line
VF 134-1-2 / 83 / 33.66 / 100.0 / 1 / Standard
Lima / 72 / 33.29 / 100.0 / 1 / Standard
F-test / NS / -
*351-Lima, 413-367 Farmers 112, 452-Lima (RS1301) VF, 499-UC 82 VF, 514-Cannery Row, and 560-CXD 103 hybrid
**fruit firmness ; 1 = firm, 2 = intermediate and 3 = soft
One of the developed line; 499 x 351 (UC82VF x Lima (RS 1301)VF) was tested by farmers at Ban Maekung and Ban Hankaew in Chiang Mai. Normally, the farmers grew variety VF134-1-2 for a processing plant. After testing, the new variety was adopted for the production by the farmers and the processing plant.
Further research requires to develop these new varieties for bacterial wilt resistance, leaf curled resistance and late blight resistance. From the author’s experiences with these diseases, resistant genes rarely exist in cultivated varieties. There varieties of tomato were obtained from Department of Agriculture. They were bacterial wilt resistant varieties. They were used as male varieties to cross with our developed varieties 413 x 351, 452 x 337 and 514 x 351 at Chiang Mai University in 2000. The F1 hybrids were self-pollinated for 2 generations. They were screened for bacterial wilt resistance. However, the experiment is in the process of screening, results could not yet be presented.
Figure 1New developed winter tomato variety.
Heat tolerant tomato
Heat tolerant tomato varieties such as Seeda, Seedathip, L22 and SVRDC4 are good varieties for summer production. But they have very poor processing quality. An ideal variety which has heat tolerance disease resistance and good processing quality has been searched. The efforts seem to be unsuccessful.
Heat tolerant varieties 667(CL5915-206D4-2-5-0) and 669(CL5915-223D4-2-1-0) from the Asian Vegetable Research Development Center were used as male parents. They were crossed with good winter varieties, 414, 502, 562, 567, 570, 572, 574, 579, 580 and a heat tolerant variety, CL1591-5-0-1-7. The progenies were selected by pedigree method. Good inbred lines were selected. They were tested at Chiang Mai University by using varieties Lima and VF134-1-2 as standard varieties. Some of them showed higher fruit yield then the standard varieties (Table 2). However, the differences in yields were not statistically significant. Line 502 x 669 gave the highest yield, 69.16 t/ha which was 27.61% higher than the standard varieties. Fruit firmness was also as firm as the standard ones. Yield was seconded by line 574 x 667 which gave 66.16 t/ha or 22.08% higher than the standard varieties. Fruit of the line was as good as the standard ones.
Another high yielding line was 579 x 669 which gave 61.21 t/ha or 12.94% higher than the standard varieties. However, fruit size of the line is smaller than the standard varieties and the fruit firmness was not firm. Therefore the two lines 502 x 669 and 574 x 667 were good potential varieties for screening under hot climate to identify their heat tolerance and disease resistance.
Table 2Horticultural characteristics of selected heat tolerant lines and standard varieties (late winter 1995).
Accession / Fruit weight / Fruit / Yield/ha / Fruit firmness* / Fruit / % Fruit yield vs / Remark(g) / yield/plant (kg) / (t/ha) / cavity / standard variety
54 x 667 / 85 / 2.4 / 47.53 / 2 / 3-5 / 87.70 / Developed line
414 x 667 / 82 / 3.3 / 48.16 / 2 / 3-5 / 88.86 / Developed line
502 x 669 / 81 / 3.7 / 69.16 / 1 / 2-4 / 127.61 / Developed line
562 x 667 / 75 / 2.3 / 35.85 / 1 / 3 / 66.15 / Developed line
567 x 667 / 94 / 2.4 / 45.12 / 2 / 2-4 / 83.25 / Developed line
570 x 667 / 68 / 2.9 / 51.2 / 2 / 2-3 / 94.47 / Developed line
572 x 667 / 84 / 2.8 / 37.92 / 1 / 3-6 / 69.97 / Developed line
574 x 667 / 83 / 2.5 / 66.16 / 1 / 3-6 / 122.08 / Developed line
579 x 669 / 74 / 3.1 / 61.21 / 2 / 3-6 / 112.94 / Developed line
580 x 667 / 69 / 3.4 / 48.46 / 2 / 3-5 / 89.42 / Developed line
Lima / 84 / 3.2 / 58.51 / 1 / 2-3 / 100.00 / Standard
VF134-1-2 / 100 / 3.0 / 49.88 / 1 / 2-3 / 100.00 / Standard
F-test / NS
* rating1 =firm, 2 = intermediate and 3 =soft
Code number 54-CL 1591-5-0-1-7, 414-369 Farmers 209, 502- Peto-81, 562-CX D105 hybrid, 567-N40-8-10B, 570-X212-WD251B, 572-X2974-WE220B, 574-X3333-6-3-5B, 579-X3501hybrid, 580-X3523 hybrid, 667-CL 5915-206D4-2-5-0, and 669-CL 5915-223D4-2-1-0.
Long-shelf life tomato
Heat tolerant and winter tomato have a common problem on short-shelf life of fruit after harvest. Long-shelf life of heat tolerant tomato would give good income because marketable time of tomato fruit after harvest lasts long. The long-shelf life of winter tomato is also very important not only extending life of the fruit for markets but also for processing plants. During harvesting time, tomato fruit matures in a short period, almost the same time. A capacity of the processing plants can not handle the large quantity. Therefore tomato fruits waited infront of the plants for sometimes. Long shelf life of the fruit would reduce percentage of fruit rot. However, in these studies only long-shelf life of heat tolerant tomato was observed.
Mutant genes nor1 and nor2 were used to extend shelf-life of heat tolerant tomato varieties. The mutant genes delayed ripening process of tomato fruit. Mature green fruit of varieties nor1 and nor2 could be able to stand at room temperature for 6 months without rotting. The mutant varieties were crossed with heat tolerant varieties L22, 607 (CL5 915-223-2-1-0) and 598 (CL5915-214-1-1). The hybrid was backcrossed with their recurrent parents (Nikornpun and Punrawong 1994 a and 1994 b).
Results showed that the F1 hybrid, the first and the second backcrossed progenies of variety L22 gave higher yield than variety L22 (Table 3, Figure 2). Fruit of the backcrossed populations could be kept at room temperature for longer time than variety L22. (Tables 3 and 4). The second and third generations of backcrossing such as L22 x nor 1 BC2F1, L22 x nor1 BC3F1, L22 x nor2 BC2F1 and L22 x nor2 BC3F1 showed the same fruit quality as L22 in fruit color, pH, soluble solid and total acidity. Fruit firmness of the crossing population of L22 showed higher levels of firmness than L22. In the third generation, fruit of backcrossed progenies of variety L22 showed the ability to last longer time than variety L22 when they were kept 30 days after harvest. Pupulations L22 x nor1 BC3 F1 and L22 x nor2 BC3F1 showed 36 and 30% of good fruit after 30 days, while there was no good fruit left in variety L22. Eventhough fruit yield of the populations was more or less the same as L22, but the shelf life was extended.
The same results were observed in backcrossed populations of varieties 598 and 607 (Tables 5 and 6, Figures 3, 4 and 4). Fruit yields of the F1 hybird, the first and second backcrossed populations were higher than varieties 598 and 607. Shelf life of these populations was extended longer than varieties 598 and 607 eventhough exact figure was not recorded. The second and third generations of backcrossing such as 598 x nor1 BC2F1, 598 x nor1 BC3F1, 598 x nor2 BC2F1, 598 nor2 BC3F1, 607 x nor1 BC2F1, 607 x nor1 BC3F1, 607 x nor2 BC2F1 and 607 x nor2 BC2F1, had the same fruit quality as 598 and 607 in fruit color, pH, soluble solid and total acidity. Fruit firmness of the crossing populations showed lower levels of fruit firmness than varieties 598 and 607.
Table 3Fruit yield and shelf life of F1 hybrid, backcrossed populations, varieties L22, nor1 and nor2 (February – May 1993) .
Population / Yield (g/pt) / % of yield vs L22 / % of fruit after 30 daysL22 / 880 / 100 / 0
L22 x nor1 F1 / 1,351.3 / 153 / 90
L22 x nor1 BC1F1 / 1,191.0 / 135 / 61
L22 x nor1 BC2F1 / 967.7 / 109 / 38
L22 x nor1 BC3F1 / 855.5 / 97 / 36
L22 x nor2 F1 / 1,507.3 / 171 / 54
L22 x nor2 BC1F1 / 1,176.8 / 133 / 22
L22 x nor2 BC2F1 / 646.0 / 73 / 18
L22 x nor2 BC3F1 / 916.7 / 104 / 30
nor1 / 873.3
nor2 / 904.5
LSD.05 / 370
CV / 20.1
Remark : fruit was harvested at pink stage.
Table 4 Color and quality of tomato fruit at red ripe stage of variety L22.
Population / Fruit firmness(kg/cm2) / Fruit color / pH / Soluble solid
(Brix) / Total acidity
(%)
L22 / 0.69 / Red / 4.27 / 4.17 / 0.78
L22xnor1F1 / 1.18 / Red-orange / 4.36 / 4.60 / 0.61
L22xnor1BC1F1 / 0.85 / Red-orange / 4.39 / 4.60 / 0.53
L22xnor1BC2F1 / 0.74 / Red / 4.29 / 4.33 / 0.62
L22xnor1BC3F1 / 0.75 / Red / 4.32 / 4.47 / 0.71
L22xnor2F1 / 0.01 / Red-orange / 4.18 / 4.93 / 0.74
L22xnor2BC1F1 / 0.71 / Red-orange / 4.31 / 4.47 / 0.70
L22xnor2BC2F1 / 0.70 / Red / 4.28 / 4.27 / 0.75
L22xnor2BC3F1 / 0.83 / Red / 4.34 / 4.20 / 0.68
nor1 / 3.21 / Orange-pink / 4.44 / 4.60 / 0.53
nor2 / 2.46 / Yellow / 4.44 / 3.97 / 0.44
Figure 2Tomato fruits of varieties L22, nor1, F1 hybrid, the first, second and third backcrossed progenies of variety L22.
Table 5Fruit yield and shelf life of F1 hybrid crossed backcrossed populations, varieties 598, 607, nor1 and nor2 (February – May 1993).
Population / Yield (g/pt) / % of yield female parent598 / 1,046 / 100
598 x nor2 F1 / 1,220 / 117
598 x nor2 BC1 F1 / 1,552 / 148
598 x nor2 BC2 F1 / 1,617 / 154
598 x nor2 BC3 F1 / 1,209 / 115
607 / 827 / 100
607 x nor2 F1 / 1,634 / 197
607 x nor2 BC1 F1 / 1,324 / 160
607 x nor2 BC2 F1 / 1,020 / 123
607 x nor BC3 F1 / 679 / 82
LSD.05 / 370
CV / 20.1
Table 6 Color and quality of tomato fruit at red ripe stage of varieties 598 and 607.
Population / Fruit firmness(kg/cm2) / Fruit color / pH / Soluble solid
(Brix) / Total acidity
(%)
598 / 1.98 / Red / 4.32 / 4.43 / 0.57
598xnor1F1 / 1.78 / Red-orange / 4.31 / 4.13 / 0.61
598xnor1BC1F1 / 1.65 / Red-orange / 4.37 / 4.57 / 0.54
598xnor1BC2F1 / 1.43 / Red / 4.28 / 4.40 / 0.52
598xnor1BC3F1 / 1.46 / Red / 4.31 / 3.93 / 0.63
598xnor2F1 / 1.27 / Red-orange / 4.35 / 4.13 / 0.64
598xnor2BC1F1 / 1.35 / Red-orange / 4.24 / 4.50 / 0.57
598xnor2BC2F1 / 1.42 / Red / 4.40 / 4.33 / 0.53
98xnor2BC3F1 / 1.48 / Red / 4.33 / 4.27 / 0.54
607 / 2.39 / Red / 4.38 / 3.57 / 0.53
607xnor1F1 / 2.20 / Orange-red / 4.36 / 3.70 / 0.58
607xnor1BC1F1 / 1.99 / Red-orange / 4.41 / 3.77 / 0.51
607xnor1BC2F1 / 1.74 / Red-orange / 4.42 / 3.50 / 0.52
607xnor1BC3F1 / 2.05 / Red / 4.42 / 3.67 / 0.49
607xnor2F1 / 1.32 / Orange-red / 4.27 / 4.53 / 0.52
607xnor2BC1F1 / 1.53 / Orange-red / 4.45 / 3.60 / 0.48
607xnor2BC2F1 / 1.44 / Red / 4.47 / 3.73 / 0.56
607xnor2BC3F1 / 2.21 / Red / 4.46 / 3.63 / 0.41
nor1 / 3.21 / Orange-pink / 4.44 / 4.60 / 0.53
nor2 / 2.46 / Yellow / 4.44 / 3.97 / 0.44
Figure 3Tomato fruits of varieties 598, nor2, F1 hybrid, first, second and third backcrossed progenies of variety 598.
Figure 4Tomato fruit of variety 607 (left) and the first backcrossed progeny of variety 607 (right).
Figure 5Tomato fruits after 30 days on shelf.
CONCLUSIONS
From the initiation of FAO project in 1980, many breeding programs on tomato started at Chiang Mai University. Improvement of tomato production technology was the target of the project. Good variety of tomato is an important factor behind the technology. The good technology can not be fulfiled if tomato variety is poor. Therefore high yielding, disease resistant, good quality, high temperature tolerant and long shelf life tomato varieties have been developed.
A few good winter tomato lines such as 452 x 351 and 499 x 351 were developed from commercial winter tomato varieties. They showed higher yield than the standard varieties. Their fruit firnness was also as good as the standard ones. One line was tested at farmer’s field by farmers nearby Chiang Mai. They adopted the line for production.
Improvement of heat tolerant tomato varieties for long shelf life. Mutant genes nor1 and nor2 was transferred to varieties L22, 598 and 607 by backcrossing. Results showed that the progenies gave better yield than the heat tolerant parents. The fruits of these progenies could be kept under room temperature for sevaral weeks longer than the parents.
Winter tomato varieties were crossed with 2 heat tolerant varieties 667 and 669. Inbred lines for heat tolerance were selected by pedigree selection. Heat tolerance with good processing quality were the criteria. A few inbred lines such as 502 x 669 and 574 x 667 were as good yield and good fruit firmness as the standard varieties. However, further screening for heat tolerance and disease resistance should be observed.