Growth habit and the number of leaves between successive trusses along the main stem was observed on plants from interspecific crosses between L. peruvianum (L. p. CMV sel. INRA) and five determinate L. esculentum (sp) varieties.
L. peruvianum CMV sel. INRA was selected for CMV resistance in progeny of a cross of (PI 126926-AlxA6) x (PI 128648-6). The two parents were selected for CMV resistance, the former in Montfavet and the latter in Japan. Growth is indeterminate, however, the number of leaves between successive inflorescences is regularly two. F1 and BC1 plants were developed from in vitro culture of immature embryos of the interspecies hybrids. In vitro plantlets could not be transferred to soil at the same time, so cuttings of F1 and BC1 plants were grown to carry out a second observation under identical conditions.
All 13 F1 hybrids were indeterminate in growth habit (Table 1) and closely resembled their L. peruvianum parent with regards to the number of leaves between successive inflorescences (ranging from 1.9 to 2.3 - average 2.1). Segregation for determinate growth habit occurred after back crossing Fl plants with " varieties. Sixteen BC1 plants of 37 displayed indeterminate growth and the number of leaves between successive inflorescences ranged from 1.7 to 2.6 similar to L. peruvianum (Table 2). Three nodes between inflorescences characteristic of indeterminate L. esculentum cultivars was not observed. Similar observations were reported in F1 hybrids between L. esculentum lines and L. parviflorum (Philouze, TGC 29:29-30).
The occurrence of two nodes between inflorescences in indeterminate hybrid of L. peruvianum as well as L. parviflorum suggests that this germplasm may prove useful to develop indeterminate L. esculentum cultivars with two or fewer nodes bretween trusses.
Table 1. F1 plants. Average number of observed trusses and leaves between successive trusses.
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F1 plants Fl cuttings
Number Average number Average number
of of observed of observed
F1 F1 plants trusses leaves trusses leaves
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Anita(sp)x L.p. CMV sel INRA 3 5.3 2.23 9.7 2.00
Petogro(sp)x " 1 6.0 2.00 11.0 2.15
Peto 94(sp)x " 5 8.8 2.00 10.6 2.15
Lima(sp)x " 1 7.0 2.20 10.5 2.05
Rio Fuego(sp)x " 3 4.7 2.20 9.7 2.07
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Table 2. BC1 plants. Average number of observed trusses and leaves between
successive trusses.
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Indeterminate growth
Number of BC1 plants BC1 cuttings
BC1 Avg. number Avg. number
plants of observed of observed
BC1 sp sp+ trusses leaves trusses leaves
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Anita x F1(Anita x 4 5 8.0 2.02 8.4 2.35
L.p. CMV sel. INRA)
Petogro x F1 (Petogro x " 2 - - - - -
Peto 94 x F1 (Peto 94 x " 1 - - - - -
Lima x F1 (Lima x " 2 2 9.0 2.57 8.0 2.38
Rio Fuego x F1(Rio Fuego x " 3 5 6.3 2.27 8.4 2.39
Anita x mixed - 1 7.0 2.00 9.0 2.25
pollen of all F1 plants
Lima x " 6 - - - - -
Rio Fuego x " 3 3 6.7 2.04 9.0 2.44
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