Construction of healthy seedling index and quality evaluation of growth process for tobacco seedlings
To build a scientific evaluation system of healthy seedlings for quickly, accurately, intuitively and comprehensively judgement of tobacco seedlings quality and quality evaluation threshold in the process of tobacco seedling growth under the control of greenhouse facilities, in this paper, based on the measurement data of tobacco seedlings (60 days after sowing), the comprehensive evaluation index (CEI) of tobacco seedlings was constructed using fuzzy comprehensive evaluation method and entropy method, the key indicators for healthy seedlings selected by K-means clustering analysis were randomly combined into 30 healthy seedling indexes (HSI), and the optimum HSI was screened through the correlation analysis between the HSI and the CEI. Furthermore, another batch of to-bacco seedlings in the growth and development period (30 - 60 days after sowing) were also measured and analyzed, and the period when tobacco seedlings reached the level of healthy seedlings and the threshold of key indicators of healthy seedlings were obtained. The results showed that: 1) There were significant differences between groups of three trays of tobacco seedlings in different positions in the facility greenhouse. 2)The CEI ranged from 0.377 to 0.778, and the optimum HSI was plant fresh weight × Chlorophyll × underground dry weight / plant height (r=0.766). 3) The quality of tobacco seedlings was divided into three grades, the best healthy seedling grade (HSI ≥ 0.519), healthy seedling grade (HSI: 0.356-0.519), and the weak seedling grade (HSI ≤ 0.356). 4) In addition, about 50 days after sowing, tobacco seedlings reached the optimal healthy seedling level, of which the plant height was about 6.96 cm, the plant fresh weight was about 7.59 g·plant-1, the aerial part dry weight was about 0.35 g·plant-1, and the chlo-rophyll was about 1.36 mg·g-1. These findings provide revealing insights into scientific evaluation of tobacco healthy seedlings and precise regulation of healthy seedling formation process.
万方数据
维普
