Assessment of Intraspecific Diversity and Screening of Elite Genotypes of Atriplex canescens as a Host Plant for Cistanche deserticola

Screening superior hosts is critical for artificial cultivation of <i>Cistanche deserticola</i> Y.C.Ma. However, intraspecific trait variation and host suitability of its emerging host <i>Atriplex canescens</i> (Pursh) Nutt remain unsystematically evaluated. In this study, 31 <i>A. canescens</i> individuals with diverse morphotypes and parasitic statuses were selected from over 300 seedlings. After post-transplant assessment, 17 representative <i>A. canescens</i> genotypes were selected and cutting-propagated. Their genetic, phenotypic and photosynthetic traits were systematically analyzed by multiple approaches, with a multi-indicator evaluation system built by correlation analysis and entropy-weighted Technique for Order Preference by Similarity to Ideal Solution)(TOPSIS). The results showed that the Internal Transcribed Spacer(ITS) sequences of the selected genotypes had an approximate length of 644 bp, exhibiting an average GC contents of 58.35%. A total of 22 haplotypes were detected, indicating high genetic diversity. In this study, superior host genotypes were defined as those with relatively excellent growth potential and stable, efficient photosynthetic performance. NP3.13, P3.1 and NP2.23 were recognized as promising candidate host genotypes with potential for <i>C. deserticola</i> cultivation, and their host suitability was indirectly inferred from their relatively superior growth and photosynthetic traits. This study not only provides valuable candidate germplasm resources and a scientific basis for optimizing the cultivation of <i>C. deserticola</i>, but also furnishes methodological support for elite genotypes screening in other plant species by the established evaluation framework.