The Genetic Diversity Analysis of Collected Sorghum Based on Agronomic Traits and SSR Markers
Date Issued
2014
Date
2014
Author(s)
Hsieh, Wei-Hsun
Abstract
Sorghum (Sorghum bicolor (L.) Moench) is the fifth most important cereal crop
in the world. Sorghum is an important staple food for people who live in semi-arid
regions because of its drought tolerance and high ability of environmental adaptation
In addition, it can be used as forage, feed crop, broom, and bio-ethanol production. As
a result, sorghum is a multipurpose crop. Assessing the genetic diversity of sorghum
germplasm is essential to breeding programs. We investigated the collected sorghum
accessions by evaluating phenotypes in the field and genotypes of DNA marker,
simple sequence repeat (SSR). The sorghum germplasm were obtained from 1)
National Plant Genetic Resources Center; 2) Department of Agronomy, National
Taiwan University (NTU); and 3) fields in all parts of Taiwan. We planted 48 sorghum
accessions according to complete random design (CRD), five replicates for each
sorghum accessions, in the experimental farm at NTU in fall 2013. Then we measured
five important traits, including plant height, tiller number, panicle length, heading date,
and panicle number. The results showed that plant height was ranged from 25 to 204
cm; tiller number was ranged from 0 to 8; heading date was ranged from 59 to 195
days; panicle number was ranged from 1 to 23; and panicle length was ranged from 6
to 44 cm. These results implied that sorghum accessions highly diversified at the
morphological level. The sorghum accessions demonstrated high level of genetic
diversity based on the cluster analysis by phenotype data. The Taiwan collected
accessions were clustered together, and so as the forage and waxy sorghum.
Furthermore, a total of 53 SSRs were used to evaluate genetic diversity of 93 sorghum
germplasm. Averagely, 14.4 alleles were detected per locus, and the polymorphic
information content (PIC) value ranged from 0.206 to 0.922 with a mean of 0.709,indicating high discriminating ability of SSR markers used. The Nei’s genetic distance
ranged was from 0.055 to 0.983, implying that the substantial difference among the
sorghum accessions. The sorghum germplasm were divided into three clusters based
on the phylogeny tree using neighbor-joining. The Taiwan collected accessions were
in a subgroup of the second cluster; the forage sorghum accessions were in the third
cluster. Moreover, S. propinquum and S. halepense were all in the first cluster. The
result of Principle Coordinate analysis was largely identical to phylogeny analysis for
which S. propinquum and S. halepense were belonged to the third range and the
Taiwan collected accessions belonged to the sixth range. According to STRUCTURE
analysis, sorghum germplasm were divided into eight subpopulations. Taiwan
collected accessions were separated into two different subpopulations, indicating that
the genetic background among Taiwan collections were similar to each other; on the
other hand, the germplasm of Sorghum genus were grouped in one subpopulation,
though admixtures were observed. In summary, the levels of polymorphism of SSR
markers used in this study were very high, and it might help explore some sorghum
germplasm with potential. Either through agronomic trait or marker analysis, the
genetic diversity among the collected sorghum germplasm was highly diverse. This
study established the fundamental of sorghum genetic reseach and provided useful
information to sorghum breeding programs.
Subjects
遺傳歧異度
高粱
農藝性狀
Type
thesis
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