Effects Of Environment And Seedling Age On Seedling Growth, Transplanting Quality And Dry Matter Production Of Hybrid Indica Rice

Environmental factors such as light, temperature and humidity, play important roles in rice growth. Greenhouse is an emerging seedling cultivation environment different from field, and it is a scant sunlight environment with different temperature and humidity different from field. Planting mechanization have strict seedling age for morphological differences. Little research has been done on the effects of seedling age and substrate on rice seedlings in greenhouse. Therefore, this study has the aim to investigate the effect of environment and seedling age on growth and transplanting quality of hybrid indica rice seedling in greenhouse.The experiment was designed in split plot by using Fyou 498 as material. Comparing meteorological characteristics of the two seedbed, effects of Heng Aoda and nutrient soil and different seedling ages with 20 d,30 d and 40 d on seedling quality and transplanting quality of hybrid indica rice were studied in 2014, effects of different seedling ages with 20 d,30 d,40 d and 50 d on seedling quality, transplanting quality, dry matter production, yield and its components of hybrid indica rice were studied in 2015. The main results were as follows:1. The temperature, relative humidity and light intensity of greenhouse seedbed were similar to these of field seedbed, and diurnal variation in temperature, relative humidity and light intensity of greenhouse seedbed lagged behind these of field seedbed. Light intensity of greenhouse seedbed was lower than field seedbed and temperature of greenhouse seedbed was higher than field seedbed. The internal light intensity of film was slightly lower than external light intensity of film in field seedbed, but internal temperature and relative humidity of membrane was lower than external temperature and relative humidity of membrane in field seedbed.2. The seedling growth in greenhouse was two segments with fast early and slow rear.The seedling with 30 d seedling age was suitable for planting mechanization for the lowest rate of empty hills and higher number of plants per hill. However, the seedling with long seedling age had poor transplanting quality for the highest rate of empty hills, the highest rate of injury hills, the highest rate of float hills and the lowest number of plants per hill. The seedling in greenhouse could be suitable for long seedling age by properly controlling seedling growth with temperature, relative humidity and light intensity regulation to increase scope of seedling age for planting mechanization. The nutrient soil seeding had better transplanting quality than Heng Aoda seeding with high rate of empty hills and high rate of float hills, but substrate seeding had small injury for its loose property on planting mechanization. Thus, the substrate was considered to support seeding in greenhouse for low rate of injury hills by further research. The temperature, relative humidity and light intensity had an impact on seedling quality and transplanting quality including a great effect of temperature on leaf area, leaf age and dry weight, and accumulated temperature was significantly correlated with the leaf age. The temperature, relative humidity and light intensity had an impact on rate of float hills and number of plants per hill and was not significantly correlated with the rate of empty hills and rate of injury hills.3.The height of long seedling age was too high in field seedbed, it was prone to injury when transplanting, and its root-developing ability declined to the disadvantages of early tillering and dry matter accumulation. Different seedling ages had insignificant effect on dry matter accumulation in greenhouse seedbed, and difference of hybrid indica rice's transplanting-matury time with 20 d seedling age,30 d seedling age,40 d seedling age and 50 d seedling age were very small. The difference of morphology between various seedling ages was small and difference of its yield and yield components were not significant in greenhouse, thus greenhouse is a more conducive seeding environment for stable yield. The mediun-short seedling ages shorten seedling raising time and reduce growing period, and they can save the cost of seedling on planting mechanization at the same time. Therefore, greenhouse can conduct multiple batches of seeding to increase economic efficiency when seedling raising period.