In Vitro Conservation And RAPD Analysis Of Banana (Musa Spp.)Germplasm In Fujian

In this experiment the germplasm of banana (Musa spp.) in Fujian Province was investigated and 53 accessions of them were used as materials for the studies on in vitro conservation and morphological identification; and by the means of RAPD analysis, the genetic diversity and cluster analyses of the 10 main cultivars and the wild banana in Fuzhou and Sanming in Fujian were conducted . The main results were as follows:1. The investigation and observation of Fujian wild bananaThe wild banana was widely distributed to Fujian Province. Because of seeding largely, Fuzhou wild banana might belonged to diploid. According to the categories of Simmonds and Shepherd (1955) , the most characters of Fuzhou wild banana were same as M.acuminata. and it was scored 22. Therefore, Fuzhou wild banana was classed to the AA group. However, on the arrangement of the ovule and the shape of fruit, Fuzhou wild banana was different from the original species of AA. Fuzhou AA wild banana was genetically distinguished from the original species, and it might take a few genes from the B-group chromosome in the evolutionary development. Sanming wild bnanana was different from the Fuzhou wild banana, and it was scored 22, so it was classed to AB group.2. In vitro conservation of banana germplasm (Musa spp.) in FujianThe obtained results showed that the banana clusters could be conserved for 6 months on the MS medium added 30g/L mannitol, 1.0 mg/L6-BA and 0.1 mg/L IAA at the room temperature of 20+1℃with the light (1000Lux) of 16h/d; added mannitol suppressed the growth of plantlets effectively, which was stronger than sucrose did; the medium added BA could prolong the subculture time than that of with KT; the effect of different low concentrations of auxins was not significant. According to the above methods, 53 accessions of banana germplasm in Fujian were successfully conserved.3. Genomic DNA extraction and optimization of RAPD-PCR analytic conditions of bananaBy the CTAB improved method, the pure, high-yield and high-quality genomic DNA frombanana was extracted from the leaves, and then some important reaction parameters and procedures for the RAPD reaction program were developed, and the stable RAPD reaction system was established and optimized, which were suitable for the study of genetic diversity and segregation of banana genetic resources in Fujian Province.The RAPD amplification system for banana was in a 25μL reaction mixture containing 50 ng DNA template of the banana cultivars. 62.5ng DNA template of the wild banana, 0.8 n mol·L^-1 primer, 1.0 unit Taq DNA polymerse of the banana cultivars, 2.0 unit Taq DNA polymerse of the wild banana and 2.5mmol·L^-1 mg²⁺, 300μmol·L^-1 dNTP. The optimized amplification program for banana RAPD-PCR was: 45 cycles at 94℃for 60s, 37℃for 60s and 72℃for 120s; 72℃for 600s. 4. Analysis of the genetic relationship by RAPD among the 10 accessions of cultivated or wild banana in Fujian ProvinceThe results of the RAPD analysis of the 10 accessions of cultivated or wild banana in Fujian Province indicated that Fuzhou wild banana and Sanming wild banana were distinguished from the other triploid cultivated cultivars at the threshold value of 0.52; at the threshold value of0.30, Fuzhou wild banana was distinguished from Sanming wild banana in focus, which was identical to the classification of Simmond. However, the dissimilitude factor between Fuzhou wild banana and AAA group was bigger than that between Fuzhou wild banana and ABB group, which suggested that the genetic distance of Fuzhou wild banana to ABB group was closer than to AAA Group. This was different from the result of Simmond classification, which was related to AB heterozygote of Sanming wild banana, segregation of self-cross and rich of natural variations.5. Analyses of the genetic diversity and clustering of Fuzhou and Sanming wild banana in Fujian Province by RAPDThe RAPD analyses from 16 individuals of Sanming wild banana and 21 individuals from Fuzhou wild banana by POPGENE sofeware showed that: (1) Nei's gene diversity(h) of the populations of Sanming wild banana was 0.4110, and that of the populations of Fuzhou wild banana was 0.4003; the mean number of alleles(na) of Fuzhou and Sanming wild banana was 2.0, and the effective number of alleles of Sanming and Fuzhou wild banana was 1.7164 and 1.3249, respectively; Shannon Index of diversity (I) of the populations of Sanming wild banana was 0.5995, while that of the populations of Fuzhou wild banana was 0.4003, which suggested that the genetic diversity of the populations of Fuzhou and Sanming should be high because of their wide geographic distribution; (2) Genetic diversity of the population of Sanming wild banana was higher because the habitat of the populations of Sanming wild banan ranged widely and was not destroyed; (3)The results of the genetic diversity analysis showed that there was 4.84% of the variance between the populations of Sanming wild banana and the population of Fuzhou wild banana and Nm was 9.8373, which suggested that the variation occur within the population in Fuzhou or Sanming wild banana and the geographical isolation exist between the two populations.