Identification of F1 Hybrid Progenies in Mango Based on Fluorescent SSR Markers

Mango (Mangifera indica L.) belongs to the genus Mangifera and family Anacardiaceae, and is an important tropical fruits. Artificial cross breeding (hand pollination) is an important method for breeding new mango cultivars. It is easy to produce false hybrids in the process of artificial pollination breeding. Therefore, it is necessary to establish rapid and accurate molecular detection methods to identify the authenticity of hybrids. Mango 'Jinhuang' and 'Renong No.1 ' and 65 individual plants of their F-1 hybrids were used as experimental materials, eight SSRs (simple sequence repeats) primer pairs with polymorphism in parents were used to identify the F-1 hybrids by capillary electrophoresis. The results showed that PCR product size (bp) for eight primers ranged from 108 bp (ES55) to 176 bp (ES63) in 65 samples. A total of 62 true hybrids were identified from 65 hybrid progenies, and the true hybrid rate was 95.38%. A total of 18 alleles were amplified by eight SSRs, seven SSR loci showed binary segregations, whereas only one SSR locus ES83 showing ab:ac:bb:bc segregation fitted to the expected segregation ratio of 1:1:1:1. The value of expected heterozygosity (He), ranged from 0.34 to 0.62, whereas the value of observed heterozygosity ranged from 0.44 to 0.81. Chi-square test showed that eight SSR loci were in accordance with Mendel's segregation law. The results of cluster analysis showed that the parents and 62 true hybrids could be classified into two categories at 0.58: the first category contained 27 offspring, clustered with 'Jinhuang' and showed a maternal genetic tendency. The second category contained 35 offspring, clustered with 'Renong No.1 ' and showed a partial paternal genetic tendency. DNA fingerprint of hybrids from 'Jinhuang' x 'Renong No.1 ' cross were constructed using eight SSR primers for variety protection.

Automated summary

This study aimed to establish a rapid and accurate molecular detection method to identify the authenticity of hybrids in mango breeding. By using SSR primers and capillary electrophoresis, 62 true hybrids were successfully identified, and different SSR loci showed different genetic segregation patterns. Cluster analysis results showed that the parents and hybrids could be classified into two categories, which is helpful for mango variety protection and genetic research.