Evaluation for Photosynthetic Characteristics in upland cotton germplasm based on chlorophyll a fluorescence

Background: The research of photosynthetic characteristics of germplasm resources of cotton ( Gossypium hirsutum L.) provides reference for genetic improvement on cotton cultivars. Chlorophyll a fluorescence (CF) is widely used for analysis of photosynthetic activity of plants leaves. However, large number of Chlorophyll a fluorescence parameters (CFPs) and inconsistency CFPs application in different studies confuse researchers, which greatly limit the accuracy of photosynthesis analysis. In this study, all 53 CFPs of 189 upland cotton cultivars (strains) measured by handy PEA were screened at 12:00 and 17:00 separately. Results: 9 CFPs including PI(abs), DIo/CSo, PI(abs, total), Sm/T, Vj, Eto/CSo, REo/CSo, RC/CSo and N at 12:00 and 8 CFPs including PI(abs, total), PI(abs), DIo/CSo, Sm/T, REo/CSo, N, Vj and Eto/CSo at 17:00 are suitable for screening of upland cotton cultivars (strains). The screened CFPs classify and evaluate the photosynthetic characteristics of upland cotton cultivars (strains). Conclusions: CFPs selected can be effect and consistent parameters to evaluate photosynthetic activity of cotton germplasm.