Chinese Bulletin of Botany ›› 2017, Vol. 52 ›› Issue (4): 520-529.DOI: 10.11983/CBB16138

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Establishment of a Comprehensive Evaluation System for Chilling Tolerance in Melon Seedlings Based on Principal Component Analysis and Cluster Analysis

Yafeng Zhou, Yanbin Xu, Yanling Wang, Qiong Li, Jianbin Hu*   

  1. College of Horticulture, Henan Agricultural University, Zhengzhou 450002, China
  • Received:2016-06-27 Accepted:2016-11-11 Online:2017-07-01 Published:2017-05-05
  • Contact: Hu Jianbin
  • About author:

    # Co-first authors

Abstract: The present study aimed to establish a system for evaluating chilling tolerance in melon seedlings and select the chilling-tolerance germplasms. Overall, 19 melon germplasms with different genetic background were used as experimental materials and their seedlings were measured for 9 morphological indices and 8 physiological indices under low temperature stress. Multiple statistics analyses (e.g., principal component analysis, cluster analysis, and regression analysis) were used to analyze the chilling-tolerance coefficients (α value) of the indices and evaluate the chilling tole- rance of the melon germplasms. Obvious variation was observed with the α value of both morphological and physiological indices of the seedlings (coefficient of variation >10%) under low-temperature stress, particularly for the α value of physiological indices. By principal component analysis, the primary 17 indices were changed to 7 separate comprehensive indices with a cumulative contribution rate 84.64%. The comprehensive evaluation value (D value) for each melon germplasm was obtained by calculating their membership function values and then weighting the values with the contribution rate of the 7 principal components. According to the D values, all melon germplasms were clustered into 3 groups: chilling-tolerance (1 accession), medium chilling-tolerance (11 accessions), and chilling-sensitive (7 accessions). Finally, stepwise regression analysis was used to establish a mathematic model (forecast accuracy >93.0%) for evaluating the chilling tolerance of melon seedlings: D=0.048+0.048POD-0.119SOD+0.097PRO+0.042CRI+0.084RDW+0.206OFW. The evaluation system established was suitable for rapid examination and prediction of chilling tolerance of different melon germplasms and may also be widely used for screening chilling-tolerance germplasms and cultivar breeding.