Study on cytogenetic and karyotypic correlation in Tea (Camellia sinensis L.) genotypes
2001
GHOLAMI, MEHRAN | FALAKRO, K. | GOMAR, M | TAHERI, I | SAIIAR, SH
Tea is one of the most important beverage crops with caffeine worldwide. Breeding and releasing of high yield and quality cultivars need to know tea plant genetic. In order to survey genetic diversity among 9 tea genotypes, karyotype study carried out using squash method. The results showed that á-Bromo Nafthaline for 8 h, Farmer solution and Hemataxilin was the best combination for tea cytogenetic study. The root tip of tea cuttings were pretreated by á-Bromo Nafthaline for 8 h and then fixed by farmer solution. The tissues were softened to separate the cells by boiling them in HCL, and then roots stained with Hemataxilin solution. Some of the chromosome parameters including total length, long and short arms length, arms ratio to each other, arms ratio to total length and centromeric index were measured on microscopic photographs of the meiotic cells (r=3) using micrometer (0.01mm). Analysis of variance showed significant differences among genotypes, chromosomes and the interactions, for all of the measured parameters. The studied teas had metacenteric and submetacenteric chromosomes. Also, in terms of total length of chromosomes, the genotypes were divergence in karyotype correlation. A number of statistics (TF%, L/S, DRL and TL) were estimated to assess the karyotipic symmetry of the genotypes to find relationship between genotypes. The results showed that the genotypes 1 and 2 were the most asymmetric and genotypes 3 and 8 were the most symmetric, based on TF%. Ordination based on principal components analysis (PCA) presented that more than 97% of total diversity with two components is described. Centromeric index and long arm length had the most roles in the components, respectively. Cluster analysis, also, using Ward method grouped the genotypes in four clusters, similar to result of PCA Bi-plot, approximately.
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