Phenotypic Traits And Genetic Evaluation Of Loquat(Eriobotrya Japonica Lindl.) Germplasm Resources

Loquat[Eriobotrya japonica (Thunb.) Lind.] a species native to China, is among specialty of evergreen trees in China, which sprout in fall, flower in winter, fruit in spring and mature in summer thus making it to be known as the best fruit. Loquat has always had special tribute in he royal courts since the Tang dynasty because of its fine quality. It is particularly famous in tangqi and huangyan in Zhejiang, and Dongting Lake in jiangsu.Studies of plant taxonomy and evolution are often based on morphology, with many previous studies on loquat classification being done in order to understand their diversity and relationships. Present classification of loquat varieties is also based on morphological, but this method has drawbacks which include:several varieties having the same name but are actually different varieties or the same variety being known by different names, species being severely degraded hence becoming of inferior quality, and scientific research lagging behind. All these problems have hindered further improvement in loquat production and quality. In this paper, a combination of morphological aspects and RAPD molecular marker technology was used to study the genetic relationship of loquat varieties, and identification of ploidy in43loquat cultivars and93seedling progenies. The main findings were as follows:1. The study took morphological characteristics (fruit characters) as factors, employed factor analysis to analyze of fruit traits, with an aim of establishing the variety with the highest comprehensive appearance score, for purposes of promoting its development and utilization.2. A combination of morphological features with RAPD Markers, agarose gel electrophoresis and polyacrylamide gel electrophoresis (PAGE) was used for analysis of genetic relationships between the different loquat germplasms. This can enable breeders to provide complete genetic background information on loquat varieties from morphological features to DNA molecules markers. While comparing genetic cluster analysis results obtained from the two electrophoresis systems, the results of PAGE electrophoresis with Loquat classification were found to be more consistent.38randomly selected fragments were cloned and sequenced with results showing that37fragments except one were corresponding to amplified products of RAPD primers. Among these fragments,6were protein-coding genes, indicating that the RAPD amplification of the genome not only on the non-protein-coding sequences, but also on the protein-coding genes, is able to reveal the similarities and differences between loquat germplasm thus providing ideal genomic information from DNA markers.3. Ploidy identification has a very important role in plant genetics and breeding. From the1970’s, scholars at home and abroad have studied ploidy in a number of crops. For example in one study a positive relationship was found to exist between the of number stoma chlorlplasts in guard cells and ploidy. In this study, the relationship of stomatal guard cell chloroplast number and ploidy were found to differ among the43loquat varieties and93seedlings of offspring in a germplasm resource nursery. These results on analysis of variations in the chloroplast number between different loquat germplasm are valuable for further ploidy identification.