Summary: | 碩士 === 國立中興大學 === 園藝學系 === 87 === Experiments were conducted to study the growth and yields of tomato plug seedlings raised at different altitudes and of different ages. Tomato variety Sheng-Neu and Known-You 301 were used as plant materials in this study. Results indicated that seedlings raised at lowland (180m elevation) had significantly higher total above ground biomass than those raised at highland (1,700m elevation). Consistently, the dry weight of tomato plug seedling increased as seedling age increased. However, the dry weight increment at seedling age from 6 to 8 weeks was much less than the increment from 4 to 6 weeks, which may possibly indicate that the growth of tomato seedlings in 128-cell plug trays was inhibited after the seedlings age of 6 weeks.
Among the four different evaluation methods, the parameters of shoot dry weight to root dry weight ratio or stem diameter to plant height ratio were found to be two good ways to evaluate the seedling growth vigor. Seedlings raised at highland had slower growth and were smaller in size than those raised at low land. However, these plants had more vigorous growth and could catch up or even surpass the growth of seedlings from low land after being transplanted for 20 days to 25 days. Seedlings of 8 weeks old usually bare the first inflorescence at higher node position and flowered after longer vegetative growth period than seedlings of 4 or 6 weeks old. Seedlings of both varieties if transplanted at 4 weeks old had the highest final yield. Yet, the effect of seedling age on early yield was found significant on Known-You 301 variety only. As compared to the seedlings raised at low land, plug seedlings from highland bare the first inflorescence at 2.9 to 6.0 nodes lower position, flowered at 6.3 to 13.7 days earlier, and had 285 to 1,217g increase in the early fruit yield. Therefore, to grow fall season tomato crops in Taiwan, it is suggestible that the growers raise the plug seedlings at highland until 4 to 6 weeks old than transplant them into low land field so as to increase early yield and obtain higher profits.
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