This document discusses different methods for handling segregating plant generations in crop breeding, including the pedigree method, bulk method, and backcross method. The pedigree method involves selecting individual plants across generations and maintaining pedigree records. It allows for more selection by the breeder but is more labor intensive. The bulk method involves harvesting generations in mass and selecting later, allowing for more natural selection but taking longer. Modifications like single seed descent are discussed. Early generation testing is also described to identify superior crosses and plants early on.

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2. Dr . Balasaheb Sawant Konkan Krishi
Vidhyapeeth
BY : KALLURU SUDHAMANI
ADPM/17/2555
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3. EARLIER STUDIES:
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4. WHY HYBRIDISATION?
•COMBINATION BREEDING
•TRANSGRESSIVE BREEDING
•HYBRID VARIETIES
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5. HYBRIDIZATION:
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6. METHODS FOR HANDLING OF
SEGREGATING GENETATIONS:
• Pedigree method
• Bulk method
• Back cross method
Objective – to develop pureline varieties or a mixture of pureline
varieties.
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7. PEDIGREE METHOD
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8. Procedure of pedigree method
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9. MERITS OF PEDIGREE METHOD:
 Breeder use skill and judgement for max. extent in early segregating
generations.
Improvement of easily identified and simply inherited characters.
Transgressive segregants.
Less time than bulk method.
Pedigree record – any time information.
Plants and progenies with defects and weakness are eliminated at
earlier generations – save resources and time.
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10. DEMERITS OF PEDIGREE METHOD
• Maintenance of pedigree record.
• Selection among and with in a large no. of progenies in every
generation is laborious.
• No natural selection.
• Selection for yield in F2 and F3 ineffective.
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11. Modifications in Pedigree method:
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12. SELECTION DURING SEGREGATING
GENERATIONS:
• Actually in segregating generations thousands of plants are
evaluated.
• Quick and Visual evaluation of plants should be needed.
• Reasonably effective.
• Governed by one or few major genes and often have moderate to
high heritability.
Disease res. – artificial epiphytotics.
Lodging res. – breaking strength of straw and force req. for uprooting.
Cold res. – artificial low temperature.
 No simple, quick and reliable method of selection for yielding ability.
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13. EARLY GENERATION TESTS:
• Crosses and plants likely to produce superior progeny are identified at
early stages say in F2,F3,F4.
• Main objective: select 1. superior crosses.
2. superior plants with in superior crosses.
EXAMPLES:
Jaya, Padma of rice, Suvin and laxmi of cotton, Prabhat of red gram,
Radhey of chick pea, NP var. of wheat.
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14. • First used by Nilsson – Ehle in 1908.
• Also known as mass method or population method.
• Method in which the F2 and the subsequent generations are
harvested in mass or as bulks to raise the next generations. Later
individual plants are selected and evaluated in a similar manner as in
the pedigree method of breeding.
• Two types based on the period of bulking:
LONG TERM BULK (20-30 years)
SHORT TERM BULK (6-10 years)
• Selection.
• Adaption.
• Genetic constitution.
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15. Procedure of bulk method:
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16. MERITS OF BULK METHOD:
Simple, convenient and inexpensive.
Natural selection increases the frequency of superior types in the
population.
Little work and attention needed.
No pedigree record.
Transgressive segregants.
Artificial selection may be practiced.
Suitable for studies on the survival of genes and genotypes in
populations.
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17. DEMERITS OF BULK METHOD:
• Longer time.
• In short term bulks natural selection has little effect.
• Little skill and judgement of breeder needed.
• Large no. of
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18. Modifications in Bulk method:
• SINGLE SEED DECENT METHOD:
Suggested by Goulden in 1939. Applied by Grafius in 1965 in oats.
 In F2 and subsequent generations one random seed is selected from
every plant and bulked.
In F6 about 100-500 individual plants are selected and individual
plant progenies are grown.
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21. • ARTIFICIAL SELECTION DURING THE BULKING PERIOD:
Breeder may eliminate the inferior or undesirable types especially in
short term bulks.
Mainly depends on skill and judgement of the breeder.
No pedigree record maintained.
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