Tissue culture is important for propagating high-economic ornamental plants. Regression analysis is an adequate method helpful to screen and quantify factors affecting growth trait during tissue culture. Hybrid Phalaenopsis Dtps Sogo Vivien (Dtps ‛Sogo Alice’ × P. ‛Zuma’s Pixie’) ‛F858’ plantlets at two tissue culture stages were used to test the effect of temperature and light irradiance on growth trait of root to shoot weight ratio, chlorophyll index, number of roots, and shoots nitrate content. Regression analysis was used to screen the multiple quantitative factors and express the effect of the variable with adequate equations. Modern regression techniques such as tests on single regression coefficient, categorical testing, piecewise regression, and comparing of data sets with an F-test statistics were used to analyze factors affecting the growth of plants tissue-cultured with data sets from the literature. The results indicated that modern regression techniques can be used to study factors affecting the growth of tissue-culture plantlets such as the microenvironment inside the culture vessels and the media composition.