Molecular Markers and a Quality Trait Evaluation for Assessing the Genetic Diversity of Avocado Landraces from China

Yuanzheng Liu,Yanxia Li,Ying Yang,Yu Ge,Xiaoping Zang,Rulin Zhan,Weihong Ma,Xinge Lin

doi:10.3390/agriculture10040102

Yuanzheng Liu, Yanxia Li + Show 6 more

Open Access

https://doi.org/10.3390/agriculture10040102

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Abstract

Avocado is an economically important crop that is widely cultivated in the tropical and subtropical regions of China. However, there is a lack of sufficient information regarding the racial origins and genetic diversification of native avocado germplasm. On the basis of a race-specific kompetitive allele-specific PCR genotyping analysis, the 56 avocado accessions examined in this study were classified as complex hybrids, namely Guatemalan × Mexican × West Indian hybrids. The genetic relationships among the avocado accessions were assessed based on a quality trait evaluation and molecular characterization. The total flavonoid content was relatively useful for differentiating between native avocado accessions. A cluster analysis as well as principal component and coordinate analyses of quality traits and molecular characteristics differentiated the avocado accessions, but not according to geographical origins. Thus, the artificial flow of avocado germplasm or seed exchanges among farmers within specific regions may have contributed to the similar genetic backgrounds of avocado germplasm from different collections.

Highlights

Avocado (Persea americana Mill.), which is a member of the family Lauraceae of the order Laurales, is one of the most economically important subtropical/tropical fruit crops worldwide [1,2,3]
To determine race and analyze the genetic diversity based on expressed sequence tag and simple sequence repeat (EST-SSR) markers, 56 avocado accessions with an unknown race were obtained from the Nanfeng garden of the avocado germplasm resource (Danzhou, Hainan province, China; latitude 19◦ 310 N, longitude 109◦ 340 E, and 20 m above sea level), of which 46 (BDNV-1 to BDNV-46) were continuously collected in Baodao New Village and 10 (JFPF-1 to JFPF-10) were continuously collected from the Jianfeng private farm (Ledong, Hainan province, China; latitude 18◦ 500 N, longitude 109◦ 050 E, and 50 m above sea level) since 2014
The kompetitive allele-specific PCR (KASP) genotyping results revealed that all 56 accessions were complex hybrids, namely Guatemalan × Mexican × West Indian hybrids (Table S2)

Summary

Introduction

Avocado (Persea americana Mill.), which is a member of the family Lauraceae of the order Laurales, is one of the most economically important subtropical/tropical fruit crops worldwide [1,2,3]. It is native to Meso-America, but the ‘subtropical’ ecotypes (Guatemalan and Mexican) are currently widely grown in countries and regions with warm-to-cool subtropical and Mediterranean climates. The ‘tropical’ lowland ecotype (West Indian) is grown in genuinely tropical countries and warm subtropical regions [5]. These three ecotypes have been distinguished and identified based on genetic and morphological differences [6]. Many commercial avocado accessions are often interracial hybrids of an uncertain ecotype, whether naturally occurring or induced artificially [8]

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