Injury resulting from chilling was not detected in somatic hybrid plants between S. lycopersicoides (LA1990) (+) L. esculentum cv. Sub-Arctic Maxi (Ball and Sink 1988). Progeny were subsequently obtained from some of these somatic hybrids by self- pollination and propagated asexually. Leaflets were detached from small vegetative plants following exposure to 2.5 deg.C or 20 deg.C in a 16 hr. light/ 8 dark environment for 72 hours. Chlorophyll fluorescence on these leaflets was assayed on a Brancher Model SF-10 fluorometer. Change in chlorophyll fluorescence is expressed as a C.F. ratio. Two F2 progeny, one each from SH263-3 and SH57, had a CF ratio significantly higher than Sub-Arctic Maxi, but not statistically different from LA1990. Two somatic hybrids, three F2 plants, and the sexual hybrid (LE X SL) were not different in CF ratio from the tomato parent Sub-Arctic Maxi. No differences in CF ratio were detected for plants exposed to 20 C.
Table 1. Effect of 2.5 C and 20 C for 72 hours on chlorophyll fluorescence of S. lycopersicoides, L. esculentum cv.Sub-Arctic Maxi, their sexual, somatic hybrids and F2 progeny of the somatic hybrids.
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CF Ratio
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Genotype 2.5oC 20oC
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S. lycopersicoides (LA1990) .526a .558 a
F2 SH 263-3 .502 a .593 a
F2 SH 57 .483 a .537 a
SH 57 .464 ab .595 a
F2 SH 57 .447 ab .589 a
F2 SH 23 .442 ab .557 a
SH 240 .422 ab .521 a
F2 SH 204 .402 ab .515 a
Sub-Arctic Maxi X LA 1990 .399 ab .574 a
Sub-Arctic Maxi .350 b .527 a
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L.S.D. .01 (n=10) .130 .941
Literature Cited: Ball, T., and K.C. Sink. 1988. T.G.C. 38:10.