Basic concepts of Plant Breeding

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Some basic concepts Plant Breeding of

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Some basic concepts of Plant Breeding Parents Hybrid Backcross F2, F3, F4, ………………………………………, Fn generations Inbreeding, inbred lines. Near-isogenic lines (NILs) Recombinant inbred lines (RILs) Double haploids Consequences of selfing in: Cross-pollinated crops Self-pollinated crops P1 X P2 (always homozygous) F1 x P1/P2 (Backcross) F2 F3 Fn selfing selfing selfing Homozygosity increases At the cost of decrease in heterozygosity

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Some basic concepts of Plant Breeding Parents Hybrid Backcross F2, F3, F4, ………………………………………, Fn generations Inbreeding, inbred lines. Near-isogenic lines (NILs) Recombinant inbred lines (RILs) Double haploids Consequences of selfing in: Cross-pollinated crops Self-pollinated crops Cross Pollinated Crops Heterozygous Plant Homozygosity increases after each generation of selfing Vigour decreases after each generation of selfing Continuous selfings

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Some basic concepts of Plant Breeding Parents Hybrid Backcross F2, F3, F4, ………………………………………, Fn generations Inbreeding, inbred lines. Near-isogenic lines (NILs) Recombinant inbred lines (RILs) Double haploids Consequences of selfing in: Cross-pollinated crops Self-pollinated crops Near-isogenic Lines F1 Tall Dwarf NILs Continuous selfings for 9-12 generations and selection of tall and dwarf in the same genetic background T D T D T D T D SO ON……………………

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Some basic concepts of Plant Breeding Parents Hybrid Backcross F2, F3, F4, ………………………………………, Fn generations Inbreeding, inbred lines. Near-isogenic lines (NILs) Recombinant inbred lines (RILs) Double haploids Consequences of selfing in: Cross-pollinated crops Self-pollinated crops RILs F1 F2 Each F2 is a different genotype and is heterozygous (except the parental types) Go on selfing each plant generation after generation-9-12 generations Each line is homozygous and homogeneous but tremendous variability is among the lines

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Some basic concepts of Plant Breeding Parents Hybrid Backcross F2, F3, F4, ………………………………………, Fn generations Inbreeding, inbred lines. Near-isogenic lines (NILs) Recombinant inbred lines (RILs) Double haploids Consequences of selfing in: Cross-pollinated crops Self-pollinated crops DH F1 2n Anther culture n n n n 2n 2n 2n 2n n Colchicine treatment 2n DOUBLE HAPLOID