Breeding of self pollinated crops

concept, pureline theory, method,merits,mass selection,multiline breeding adv disadv.

1. Sub.:- Fundamentals of Plant Breeding Course No. :- APB- 5211 Credit hours:- 3(2+1) Lec . Topic :- Breeding of Self pollinated crops Presented by:- Lt. Roshan Parihar , Asstt . Professor Deptt . of Genetics & Plant Breeding Indira Gandhi Krishi Vishwavidyalaya Raipur, C.G. BTC College of Agriculture & Research Station , Sarkanda , Bilaspur ,(CG)-495001 ( Pureline , Mass, Multiline Breeding)

2. 1 Breeding of Self Pollinated crops

3. General methods: Plant introduction Pureline selection Mass selection Pedigree method Bulk method Single Seed descent method Back cross method Het e rosis breeding

4. Mutation breeding Polyploidy breeding Transgenic breeding Molecular breeding Special methods: Symbols for basic crosses F : Th e sy m bo l F ( f or f i l ial) d en o te s t h e pro g e n y o f a cross between two parents. : The symbol is the notation for selfing.

5. Symbols for basic crosses  F : Th e sy m bo l F ( f or f i l ial) d en o te s t h e pro g e n y o f a cross between two parents.  : The symbol is the notation for selfing.  S: The S notation is also used with numeric subscripts. In one usage S = F 1 ; another system indicates S = F 2 .

6. Pureline selection:- It refers to the homogenous progeny of a self pollinated homozygous plant. Mass selection :- It is a method of breeding in which individual plants are selected on the basis of phenotype from a mixed population , their seeds are bulked and used to grow the next generation .

7. The known mixture of isolines , closely related lines or unrelated lines are referred to as multilines , and the method of developing a variety from any of these mixtures is known as multiline breeding. Component isogenic lines are derived through backcross breeding Multilines

8. Pure line selection

9. Johannsen (1903,1926), a Danish biologist, developed the concept of pureline theory working with Princess variety of common bean ( Phaseolus vulgaris). Pureline Theory

10. Key features: Homogeneous Nonheritable variation Highly uniform Selection is ineffective Narrow adaptation More prone to new diseases Isolation of pure lines Sources of variation

11. Pureline Breeding methodology

12. Applications Pure-line breeding is desirable for developing cultivars for certain uses: V arieties for m e c h a n i z ed pr o d u ction t h at mu s t meet a certain specification for uniform operation by farm machines. f or a dis c ri m i n a t i n g m a r k et f or vi s ual ap p e a l (e.g., u n iform shape, size). f or the p roc e s s i n g m a r k et (e.g., d e m a n d f o r c ertain ca n n ing qualities). Advancing that appear in a population (e.g., a mutant flower for ornamental use). Improving newly domesticated crops that have some variability.

13. Advantages: 1.It is a rapid breeding method. The method is inexpensive to conduct. T h e vari e t y deve loped b y t h i s m e t h od ha s great “ ey e appeal” because of the high uniformity. It is applicable to improving traits of low heritability, because selection is based on progeny performance. O n ly t h e bes t pur e li n e is s e l e c t e d f or ma xi m um genetic advance.

14. Disadvantages 1.The purity of the variety may be altered through admixture, natural crossing with other varieties and mutations. Narrow genetic base and so poor adaptability. A new genotype is not created. The method promotes genetic erosion Progeny rows take up more resources (time, space). 6.Only applicable to self pollinated species.

15. Mass selection

16.  As an ancient art, farmers saved seed from desirable plants for planting the next season’s crop, a practice that is still common in the agriculture of many developing countries.  Mass selection is often described as the oldest method of breeding self-pollinated plant species.  This method of selection is applicable to both self- and cross-pollinated species. But it is more used for cross-pollinated crops.

17. Key features  T h e p u r p o s e of m a s s s elect i o n is p op u lat i on i m p roveme n t through increasing the gene frequencies of desirable genes.  Selection is based on plant phenotype.  Mass selection is imposed once or multiple times (recurrent mass selection).  The improvement is limited to the genetic variability that existed in the original populations.  T h e goal in ma s s sele c t ion is to imp r ove t h e average performance of the base population.

18. 1 . Positive mass selection :   Desirable plants are selected from a mixed population. Base material is old varieties or land races. 2 . Negative mass selection:   Undesirable off type plants are removed from a mixed population. used for varietal purification in seed production and certification programs . Types of Mass selections

19. The success of mass selection mainly depends on three factors : Variability in the base population. Mode of inheritance of the character to be improved. Heritability of the character.

20. There are two defects of mass selection: No control on pollination. Selection is based on phenotype. Modifications are ; Rejection of inferior plants. Use of composite pollen. Stratification of field. Modifications of Mass selection

21. Cultivar development procedure

22. Purification of an existing cultivar

23. A pp l i ca tio n s to maintain the purity of an existing variety that has become contaminated. to develop a variety from a base population created by hybridization. to preserve the identity of an established variety or soon-to-be- released new variety. Some breeders use mass selection as part of their breeding program to rogue out undesirable plants, thereby reducing the materials advanced and saving time and reducing costs of breeding.

24. A dv a n t a ges It is inexpensive to conduct. The variety is phenotypically fairly uniform even though it is a mixture of pure lines . It is rapid, simple, and straightforward. The traits of interest should have high heritability. Less phenotypic uniformity than other procedures. With dominance, heterozygotes are indistinguishable from homozygous dominant genotypes. D i s adv a n t a ges

25. 22 MASS SELECTION VS PURE LINE SELECTION Single plant offsprings L1 L2 L3……. LN Register and market the best pure lines Line mixture Mass selection Pure line selection Bulk of p h en o t y pical l y similar plants Cultivar register and marketing Heterogenous cultivars Homogenous cultivars

26. M U L T I LI NE BREEDING

27. M u l ti l ine s : First Suggested IN OATS BY JENSEN IN 1952  Multilines are developed for self-pollinating species.  These cultivars consist of a mixture of specially developed genotypes called isolines (or near isogenic lines) because they differ only in a single gene (or a defined set of genes).  Isolines are developed primarily for disease control, even though these cultivars could, potentially, be developed to address other environmental stresses.  Isolines are developed by using the techniques of backcrossing in which the F1 is repeatedly crossed to one of the parents (recurrent parent) that lacked the gene of interest (e.g., disease resistance).

28. Mixtures of isolines. Mixture of closely related lines. Mixture of unrelated or distinctly different genotypes . Types of Multilines :

29. It has genetic diversity. It should have normal resistance. Components should be uniform agrnomically. It should have yield advantage. Features of Good multiline:-

30. Selection of recurrent parent. Selection of donor parents. Transfer of resistance. Mixing of isolines . Steps of Multiline Breeding:-

31. Identical to recurrent parent Loss to cultivator is low. Spreading of diseases is slow It reduces the risk of homogenising the pathogen population globally. Stabilises and optimizes production on farm. Merits:-

32. Seed is to be repaced every few years. Production and mainatenance is time taking job. It has to be regularly reconstituted, and new lines have to be continuously developed. Seed certification poses difficulties. It is less attractive, less uniform and costly method. Demerits:-

33. Multiline cultivars have been developed for commercial cultivation in oats, wheat, soybean and peanut in USA. In India three multiline varieties, viz. KSML 3, MLKS 11 and KML 7404 have been released in wheat from Punjab. Achievements:-

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