8.Rektan2-Breeding Cross PolliCrops

8/8/2019 8.Rektan2-Breeding Cross PolliCrops

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Pemuliaan Tanaman Menyerbuk

Silang(Breeding Methods in Cross Pollinated Crops)

Team MK. Rekayasa Tanaman II

Agroteknologi Fak. Pertanian UNPAD



Overview

• Genetic structure of crosspollinated crops

• Plant Features PromotingCross Pollination

• Breeding methods - Mass Selection - Recurrent Selection

- Synthetic Cultivars - Composite cultivars

Product of cross-pollination



-- Able to explain genetic structure of cross-pollinated crop

• Able to explain breeding methods in

cross pollinated crops• Able to make appropriate scheme of

particular method to breedingimportant cross-pollinated crops

Learning objectives:Learning objectives:



Self pollinating crops vs Cross pollinating

crops



Genetic structure of cross pollinated crop

• Due to

- self-sterility, - self-incompatibility, - imperfect flowers, - mechanical obstructions

• --- make plant dependent upon foreign pollen for

normal seed set.

• Each individual receives a blend of pollen from a large

number of individuals having different genotypes.• Such populations are characterized by a high degree

of heterozygosity with potential genetic variation,which is maintained in gene flow among individuals

within the populations.•



Plant Features Promoting cross-pollination

Monoecy ?Dioecy ?



Genetic structure of cross pollinatedcrops

• Each individual derives its genes from twoother individual (genetically different).

• Each individual in the population isheterozygous at many loci

• Each individual in the population isgenetically different from any otherindividual (except hybrid cultivar)

• The heterozygous nature of individual plant

is exploited

• The genes are reshuffled (susunan berubah)each generation and regrouped into new

genetic combinations



Genetic structure of crosspollinating crop

• Focus on the improvement of plantpopulations, more emphasis is given toquantitative inheritance.

• Increase the gene/allele frequency suchthat favorable genes (desirablegenotypes predominate)

• Maintain genetic variability for futureimprovements.

• FollowFollow Hardy-Weinberg (Law of geneticHardy-Weinberg (Law of geneticequilibrium)equilibrium)

•



Progeny test vs Combining ability test (Uji DayaProgeny test vs Combining ability test (Uji Dayagabung)gabung)

-- Self pollinating cropsSelf pollinating crops:: homozigothomozigot – genotipe – genotipeketurunan relatif dapat diduga, sehinggaketurunan relatif dapat diduga, sehinggaevaluasi dilakukan denganevaluasi dilakukan dengan Progeny testProgeny test (Uji(Ujiketurunan)keturunan)

-- Cross pollinating cropsCross pollinating crops:: heterozigotheterozigot- karena- karenadiserbuki oleh tanaman lain yg heterozygot, shgdiserbuki oleh tanaman lain yg heterozygot, shggenotipe keturunan sulit diprediksi– uji yg layakgenotipe keturunan sulit diprediksi– uji yg layakuntuk tanaman menyerbuk silang:untuk tanaman menyerbuk silang: uji dayauji daya

gabunggabung



Uji Keturunan pada Tanamanmenyerbuk silang

• DGU (daya gabung umum, general

combining ability): Penampilan rata-rata

ataupun total suatu genotip dalam sejumlahpersilangan dengan galur uji (tester)

•

• DGK (daya gabung khsusu, specificcombining ability): penampilan suatu

genotip pada pasangan persilangantertentu dibandingkan dg penampilanpasangan persilangan lain.

•

•



Progeny test (lanjutan)

• Test cross: (self pollinating crops: tocross with recessives genotype)

– In cross pollinating crops: crossinbred/galur with another

inbred/hybrid/known population –especially for specific combiningability (DGK)

• Top cross: Test inbred with openpollinated variety especially forgeneral combining ability (DGU);umumnya untuk seleksi awalpembentukan inbred.



Femaleparents Male parents Progeny means1 2 3 4

5 9 17 12 14 13

6 10 16 12 10 12

7 11 20 10 15 14

8 14 15 6 17 13

Progenymeans

11 17 10 14 Test Means 13

Contoh perhitungan DGU dan DGK:



For parent 2 (male)

GCA = mean of parent 2 – test mean= 17 – 13 = +4parent 2 has general ability (GCA2) of +4

SCA = lihat hasil pasangan persilangan yang memilikinilai tertinggi----- pasangan tetua 7 x 2.



Breeding Methods in Cross PollinatedCrops

Petal’s color, other traitsmay be still heterozygous



Genetic consequences of self

pollination on cross pollinating crops• Pada tanaman menyerbuk silang, bila

tanaman diserbuki sendiri

(inbreeding) dapat mengakibatkanterjadinya depresi inbreeding(penurunan rata-rata karakter/vigortertentu).

•• Inbreeding akan meningkatkan level

homosigositas dan menurunkanheterosigositas.



Inbreeding

-- The consequences of matings between

relatives is that offspring have anincreased probability of inheriting alleles

that are recent copies of the same DNAsequence that may be lethal, coding forgenetic disorders.

-

-



Inbreeding depression

Selfing, full/half-sib pollination

Reduced height, seed set,disease resistance, etcIncreased lodging,

Increased homozygosity



Mass Selection

•Same form as with self-pollinated crops

•essentially a form of maternal selection since nopollination control

•select desirable plants

•bulk seed

•repeat cycle

•with strict selection breeder willreduce population size

•slow genetic gain since lackpollination control

•must be able to identify superior phenotypes

•Not suitable for quantitative traits



Seleksi Massa Berlapis (Gardner



…………………..…………….

………………………dst

Percobaan dilakukan dengan membuat

plot-plot kecil dan seleksi dilakukan padamasing-masing plot kecil tsb, dengantujuan untuk mengurangi pengaruhlingkungan yg bervariasi

Seleksi Massa Berlapis (Gardner,1968)



Populasi campuran atau kultivar tidak murni

Seleksi Massa : pemurnian atau pembentukan populasi baru

Dipilih beberapa tanaman denganpenampilan sama dan biji dicampur untuk

ditanaman pada musim 2Musim 1 Bulk (dicampur)

Musim 2Uji hasil pendahuluan bisa beberapaulangan

Kultivar lokal/ kontrol

kultivar asal

KontrolMusim 3 – 6 Pengujian hasil lanjutan untuk dayaadaptasi dan penampilan (plot lebih

besar dan beberapa ulangan)

Perbanyakan benihMusim 7 Untuk dilepas ke petani

ulangan



Recurrent selection

Key features:

Designed to increase the frequency of desirable genes within a population

Gradually concentrating desirablealleles in a population

The concept of recurrent selection



Concept of recurrent selection

Cyclical and systematic technique in whichdesirable individuals are selected from apopulation and mated to form a new population

Improvement of a population without losing the

variability

Parents should be highly diverse

Applications:Establish broad genetic base, add new germplasm

Since possible intermating between multiple familiesadd new germplasm

Used in Legumes and grasses



TUGAS— Presentasi untuk minggu

1.2.Buat disain program pemuliaan tanaman untuk

tanaman menyerbuk silang:

Kelompok 1 : Tebu

Kelompok 2 : Bunga MatahariKelompok 3 : MentimunKelompok 4 : Kelapa dalamKelompok 5 : ubi Jalar Kelompok 6 : KubisKelompok 7 : WortelKelompok 8 : bawang merah



Format Makalah(Mendesign prog. Pemul. tnm meny. silang)

Ukuran huruf 12 time new roman, 1.5 spasi, 5-7 halaman

1.Pendahuluan (Men-set breeding goal: menguraikan tipe kultivar yg akandirakit: kultivar OP (Open pollinated) atau kult. hibrida, perkiraan preferensipetani/konsumen/user thd tnm yang akan dimuliakan serta tujuan dan targetpemuliaannya) ½ - 1 hal.

3.Upaya menciptakan variasi dan menyeleksi karakteristik yang

diinginkan (menguraikan ketersediaan plasma nutfah yg ada, upaya/metode menciptakan variasi yang diinginkan (persilangan, seleksi,introduksi, bioteknologi) sesuai tujuan & target pemuliaan sehinggadiperoleh kultivar/galur/klon harapan) 1- 2 hal.

5.Pengujian (secara singkat menguraikan bagaimana proses pengujiangenotipe-genotipe harapan dilakukan) 1-2 hal

6.Proses adopsi dan penyebaran kultivar (secara sederhana

menguraikan langkah-langkah dalam melakukan upaya adopsi danpenyebaran kultivar baru, misal melalui demplot, penyuluhan ke kelompoktani dll). 1 hal.

8.Kesimpulan .½ hal9.Pustaka (paper/text book, bukan blog, wordpress, dll) 1 hal10.Minggu depan dipresentasikan (buat Powerpointnya)



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8.Rektan2-Breeding Cross PolliCrops

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