Molecular Breeding 03

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Molecular BreedingTim Rekayasa Tanaman III

Kompetensi yang diharapkan Mahasiswa memahami penerapan marka DNA untuk membantu proses seleksi, Mahasiswa mampu memahami pemanfaatan teknologi marka DNA untuk menggabungkan beragam karakter ke dalam suatu kultivar (pyramiding).

Content Definition and objectives Marker assisted selection (MAS) MAS breeding scheme Marker assisted backcrossing (MAB) Case study of MAS Pyramiding Combined approach (phenotypic + molecular)

Gambaran: Molecular Breeding- Gen fragrance (aromatic) padi terpaut dg DNA marker RM515

F TAGGACGACCAAAGGGTG R TGGCCTGCTCTCTCTCTC

Example: introgresi gen Xa21 (gen ketahanan thd blas)

Chrom. 11

Tahan, tetua donor Rentan, recipient

Molecular breeding: Kultivar Resisten dan Rentan

gen pengendalli karakter (QTL) yang terpaut dengan DNA marker pada padi

Molecular Breeding? Penggunaan teknologi marka DNA yang terpaut atau letaknya berdekatan dengan lokus target tertentu (pengendali karakter) atau marka DNA yang digunakan sebagai alat bantu karakterisasi fenotipe suatu individu. Asumsi: marka DNA tersebut dapat diandalkan (reliable) Tujuan: membantu proses seleksi (indirect selection: seleksi berbasis DNA marker- mengeliminasi individu yang tanpa DNA marker). meningkatkan efektivitas dan efisiensi seleksi dan penggabungan karakter-karakter

Why Molecular breeding ?? Many traits can be difficult/expensive to measure or are environmentally sensitive, and thus it is difficult to make progress in breeding programs.

It is difficult to combine numerous important traits simultaneously into cultivars, markerassisted breeding gives geneticists/breeders a versatile set of tools that can augment, as well as verify, traditional selection techniques Mol. Breeding overcomes these limitations by performing an easy lab test (DNA extraction- PCR- Electrophoresis-Visualisasi)

Advantages of molecular breeding

Case study: MAS on Jatropha (Jarak pagar) genotypingIn Gh Pu QR

In Gh Pu QR

13 primer pairs selected for use in further studies These reveal 69/453 polymorphic bands (15.2%) Results indicate very little variation between accessions from India, Ghana, Tanzania & Madagascar

Conventional plant breeding

x

Cross plants, e.g., high oil cultivated with wild disease resistant

F2

Phenotypic screen of all progeny usually requires mature plants Limited by number of plants than can be brought to maturity and screened.

Selected progeny then backcrossed with cultivated variety to remove undesirable traits

Marker assisted breeding

Involves creation of a genetic map using MarkersCo-inheritance of phenotype and genotype reveals linked markers These can then be used in fasttrack breeding programmes Genotype analysis performed at seedling stage More rapid, and higher throughput than phenotypic selection Plants with correct genotype can then be subjected to phenotypic verification

Var1 Var1 Var2 Var2

h1 h2 h1 h2

ATGTTTGAACGACTTCAA ATGTTTGAACGACTTCAA ATGTTTGTACGACTTCAA ATGTTTGTACGACTTCAA *

1 1 2 2

Case study: rice

Collard & Mackill,

Marker-assisted backcrossing (MAB)

CONVENTIONAL BACKCROSSING

MARKER-ASSISTED BACKCROSSING (breeding)

P1 x P1 x F1

P2

P1 x P1 x F1

P2

BC1F VISUAL1 SELECTION OF BC1 PLANTS THATMOST CLOSELY RESEMBLE RECURRENT PARENT

PLANTS THAT HAVE MOST RP MARKERS AND SMALLEST % OF DONOR GENOME

BC1F 1 USE BACKGROUND MARKERS TO SELECT

BC2

BC2

Pyramidin g:

Pyramiding

Combined approaches (using both phenotypicand molecular marker): Tandem Selection

References Collard B & Mackill D. 2008. Marker-assisted selection: an approach for precision plant breeding in the twenty-first century. Philosophical Transactions of the Royal Society of London Series B 363:557-572. Graham I. 2007. Towards the development of new Jatropha varieties: molecular and biochemical analysis of toxic and nontoxic lines. Biology to Benefits Society. Univ of York. Semagn K, Bjornstad A and Ndjiondjop MN. 2006. Progress and prospects of marker assisted backcrossing as a tool in crop breeding programs. African Journal of Biotechnology 5:25882603. Jena KK and Mackil DJ. 2008. Molecular marker s and their use in marker-assisted selection in rice. Crop Science 48:12661276.

Quick review Molecular breeding? Why use molecular breeding? Advantages? Disadvantages? Draw breeding scheme: conventional & MAS (MAB)? Pyramiding?

Any question left?