In previous years by crossing (Alfa 385 x Midseason 164) F2 x 407 3- 4- 1- 13 the author succeeded in breeding varieties Kostovi F5 No. 9 Tm, j-2 and Kostovoi Industrialnii Tm, j-2 which have a strong upright stem of about 30 cm by height, with yield rating of 1.5-3 kg of fruits per plant and fruit weight of 52-68 g (Avdeyev, 1985).
For the purpose of breeding upright-stemmed bushy-type varieties of tomato, selection for plants with a more high stem and larger-sized fruits has been carried out. Crossing of [Volgogradskii 5/95 x F3 (alf a 385 x Breeding Line 325j)] F3 x Buff Heart and subsequent transgression selection for a larger diameter of the stem resulted in breeding bushy-type strong-stemmed lines No. 825 and No. 826, which do not lay on the ground until the end of the vegetation period. Other varieties with stem of 91-95 cm by height and fruit weight to 150-250 g were also obtained. Fruit yield from one plant reaches 2,6-4,2 kg with the density of planting 70x70 cm.
The lines bred have 1.3-1.6 times larger diameter of the main stem as compared with other varieties (see Table 1). The plants were sown by a directed method of planting on sandy soil poor with nutrition be placed 35x35 cm, assessment were done on 75 day of vegetation (1992).
Transgression selection for stem diameter resulted in absence of fruit clusters or only their rudiments on single plants with the largest stem diameter originating from a hybrid population F4-F5.
Preliminary studies on the inheritance of stem diameter trait show that large size of the stem is dominant in F1 hybrids and is determined by nuclear genetic factors (Table 2). The results obtained suggest potential for selection for thick upright stem in tomato, which might be useful for breeding machine harvest tomato varieties and for developing novel techn ologies to improve effectiveness of combine harvesting and to decrease soil contamination of fruits.
Avdeyev, Yu.I. Breeding of bushy-type tomato varieties for combine harvesting is one of the prospective approaches to selection In: Problems of Irrigated Vegetable and Melon Growing. Astrakhan, 1985. c. 18-21 (in Russian).Table 1. Polymorphism of stem diameter of tomato varieties
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Varieties Diameter of the stem in sm.
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average min. - max.
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Line 2049 1.08 +/- 0.04 1.05 - 1.11
Early 83 1.22 +/- 0.12 1.08 - 1.36
Volgogradskii 5/95 1.31 +/- 0.13 1.11 - 1.49
Backcross 720 Ora, Tm2 1.33 +/- 0.17 1.11 - 1.52
Line 4 Ora, Tm2, BER 1.58 +/- 0.28 1.33 - 1.78
Line 826-1 1.75 +/- 0.15 1.59 - 1.91
Line 825-1 1.77 +/- 0.13 1.59 - 1.91
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Table 2. Inheritance of main stem diameter of tomato in hybrid F1
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Varieties, hybrids Diameter of the stem in sm.
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average min.- max.
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Bakhtemir 2 1.47 +/- 0.04 1.43 - 1.52
Astrakhanets 1.31 +/- 0.12 1.14 - 1.46
F1 (Bakhetemir x Astrakhanets) 1.48 +/- 0.12 1.30 - 1.65
F1 (Astrakhanets x Bakhtemir) 1.43 +/- 0.17 1.25 - 1.62
Ilyinka 1.20 +/- 0.11 1.11 - 1.40
F1 (Ilyinka x Bakhtemir) 1.42 +/- 0.08 1.33 - 1.52
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