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EARLY SEEDLING GROWTH, YIELD COMPONENTS AND FRUIT CHEMICAL COMPOSITION OF HIGH-PIGMENT PROCESSING TOMATO LINES
On the arrhenius plot of temperature and daily hypocotyl growth of young seedlings just after germination under dark condition, both the hp and normal lines were approximated to two slopes with point of inflection at around 17°C. But regression coefficients of the hp lines were significantly lower than that of normal lines below the point of inflection.
This result indicates that growth of the hp lines was more suppressed than the normal lines under low temperature condition.
In F5 progenies of ‘Morioka 16′(hp) X ‘PU74–43’, the hp gene reduced the plastchron index before transplanting, the hypocotyl growth of young seedlings under low temperature, the fruit ripening speed, the ratio of early yield and total yield.
On the other hand, the hp gene increased the carotenoid and vitamin C content, and reduced the titratable acidity and citric acid/malic acid ratio.
These results indicate that the hp gene might reduce the ratio of early yield through a delay of the early growth under a low temperature condition as well as a delay in fruit ripening.
At the same time, the hp gene might result in an insipid taste of juice through a reduction of acid content and a change in the malic acid/citric acid ratio.
Although there was some inferiority in the hp lines to use as breeding material, it was thought that it might be possible to utilize the useful characteristics of high-pigment lines such as their high vitamin C and carotenoid content, because there were wide variations in the growth, yield components and fruit chemical composition in the high-pigment varieties.
Also there was no significant correlation among these characteristics.