Chalermpol Phumichai

Isolation of 55 microsatellite markers for Jatropha curcas and its closely related species

Jatropha curcas L. (physic nut) is native to Central America and now naturalized widely in many tropical and subtropical areas. Microsatellite markers were isolated and characterized. Eleven out of 55 markers showed polymorphisms, and the allelic variation was investigated using 26 accessions of J. curcas collected from several provinces in Thailand. Each marker showed 2 to 5 alleles and the average polymorphic information content (PIC) was 0.49. Thirty four markers (62 %) were also successfully amplified in J. integerrima, J. gossypifolia and J. podagrica.

Genetic diversity of physic nut (Jatropha curcas L.) revealed by SSR markers

Ten microsatellite markers were used to investigate genetic diversity and genetic structure among 32 accessions of Jatropha curcas. Low levels of average genetic diversity were observed (HE = 0.160). A dendrogram produced by the Unweighted Pair Group Method with Arithmetic Mean (UPGMA) based on Nei’s genetic distances revealed 3 groups among 32 accessions. The genetic differentiation (FST) among two groups was significant (P < 0.01). The model-based Bayesian clustering method indicated that a population structure (ΔK) was separated into two groups. The analysis of molecular variance (AMOVA) showed higher variability (63.753%) among groups than within groups (36.247%). These findings could assist in defining the best method of genetic conservation and studies in breeding programs for genetic improvement of J. curcas.

Development of specific simple sequence repeat (SSR) markers for non-pollen type thermo-sensitive genic male sterile gene in rice ( Oryza sativa L.)

A key factor of two-line hybrid rice production is the development of thermo-sensitive genic male sterility (TGMS) lines. In this study, a TGMS line showing non-pollen type thermo-sensitive genic male sterility was used. Crossing between TGMS line (female parent) and normal pollen varieties; CNT1 and PTT1 (male parent) were performed and F 1 and F 2 populations were develop for each crosses. The phenotypic segregation ratio, 3:1 (fertile: sterile pollens) observed in F 2 populations of TGMS/CNT1 and TGMS/PTT1 crosses confirmed that the non-pollen type thermo-sensitive genic male sterility is controlled by a single recessive gene. The bulk segregant analysis (BSA) using simple sequence repeat (SSR) markers were deployed to identify the location and genetic effect of this gene. We have generated new set of SSR markers to identify progenies carrying TGMS gene in a cross TGMS/PTT1. The TGMS gene was located on chromosome 2 with 0.0 cM distance from T2 marker. This TGMS gene was located in the same region of previous identified tmsX gene. It might be the same allele of this gene of 2 different lines. This marker could be used for marker assisted backcrossing to transfer TGMS gene for developing female parent in two line hybrid rice system. Key words: Hybrid rice, thermo-sensitive genic male-sterile, non-pollen type, molecular marker, marker assisted backcrossing.