The Banana Plant: Morphology, Propagation and Breeding

Banana plant
morphology
propapation and breeding

1. www.iita.org A member of CGIAR consortium The Banana Plant: Morphology, Propagation and Breeding . Training on I ncreasing the Capacity of Research T echnicians in Breeding. IITA-Ibadan, Nigeria. July 27-August 14, 2015. Amah Delphine, IITA Nigeria

2. www.iita.org A member of CGIAR consortium Plan Introduction Classification Growth cycle Morphology Pseudostem and foliage Inflorescence Flowers Bunch Propagation Breeding References and further reading

3. www.iita.org A member of CGIAR consortium Introduction Bananas are giant perennial herb mostly cultivated for their fruits. Perennial : new stems ( suckers ) continuously grow from the base of the mother plant to replace the aerial stems which die off. Herb : no woody components and aerial parts dies once bunch is harvested. Fruits may be eaten raw, steamed, roasted, fried or processed into flour. They contribute to food and income security to millions of people especially in the tropics. FAO estimates for world production in 2013 is about 145 Mt.

4. www.iita.org A member of CGIAR consortium Classification ‘Bananas’ refers to all members of the genus Musa comprising wild and edible types e.g. plantains (a well-defined group of starchy bananas ). Monocots belonging to the Eumusa section of the genus Musa (several species), family Musaceae , and order Zingiberales . Inter- and intra- specific hybrids from two ancestral species M. acuminata colla ( A genome) and M. balbisiana colla ( B genome) 2n=2x=22 chromosomes. Edible bananas of Eumusa have 22, 33, or 44 sets of chromosomes corresponding to diploids, triploids and tetraploids respectively. Ploidy is important for classifying hybrids from breeding programs.

5. www.iita.org A member of CGIAR consortium Question Name a popular banana in your country, mention its form(s) of consumption and describe how you will identify it.

6. www.iita.org A member of CGIAR consortium Classification Form of consumption : desert, cooking and beer types Genomic composition : AAA desert, highland beer and cooking bananas AAB plantains and desert bananas ABB cooking bananas AA wild and edible types BB wild types AAA-EAHB ABB AAA BB wild AA AAB

7. www.iita.org A member of CGIAR consortium Classification Height of pseudostem : Giant ( ≥ 3m, >40 leaves), Medium ( 2.1-2.9m, 32-40 leaves), Small ( ≤ 2m, <32 foliage leaves) Inflorescence type (plantains): French, F alse horn, Horn French H orn False horn

8. www.iita.org A member of CGIAR consortium Growth Cycle Vegetative phase - leaf emergence Two phases of development; Vegetative and reproductive phase

9. www.iita.org A member of CGIAR consortium Growth Cycle Reproductive phase - bunch emergence

10. www.iita.org A member of CGIAR consortium Morphology (rhizome) Rhizome (or corm) - true stem of the plant, has extremely short internodes covered by closely packed leaf scars, differentiated into central cylinder and cortex, ground tissue is starchy parenchyma . It is a storage organ sustaining growth of the bunch, and developing suckers . The terminal growing point (meristem) is a flattened dome from which leaves are formed and later becomes the inflorescence . The root system is adventitious and mostly confined to the upper 40cm of the soil. Roots originate in groups of 3-4 from the corm as primary roots branching off to secondary and then tertiary roots. It is important for the rhizome to remain completely below the surface of the soil. A phenomenon known as high mat arises when the rhizome is ‘climbing out’ of the soil resulting to plant instability and yield decline due to exposure of roots.

11. www.iita.org A member of CGIAR consortium Morphology (suckers) Suckers - lateral outgrowths from vegetative buds found on the rhizome opposite the leaf base. Propagation is by suckers and four different types of suckers are distinguished; Peeper - small sucker which has just emerged through the soil Sword sucker - narrow leaves and a broad rhizome base; ideal type of planting material Water sucker - broad leaves, smaller rhizome and weaker connection to mother plant; not ideal as planting material. M aiden sucker - full grown sucker bearing foliage leaves Several suckers are produced on the rhizome and the whole unit or clump is known as a mat . When a sucker is planted and the first bunch is harvested this is known as the plant crop . After harvest, the mother plant is cut down and a follower or daughter sucker is selected to produce the second harvest: first ratoon , the third harvest: second ratoon and so on. Water sucker Peeper Sword sucker Maiden sucker

12. www.iita.org A member of CGIAR consortium Morphology (Pseudostem and foliage) Pseudostem - looks like a stem or a trunk, formed by overlapping leaf sheaths, serves as a vascular connection between leaves, roots and fruits. Pseudostem height, aspect and colour are used to distinguish between varieties . The distal end of the elongating leaf contracts into a narrow petiole which continues into the leaf becoming the mid rib . The mid rib divides the blade into two lamina halves with pinnately arranged parallel leaf veins. The lamina develops inside the pseudostem as a rolled cylinder ( cigar leaf ) and unfolds after emergence. Older leaves senesce and die and new leaves emerge every 7-10 days. The final leaf to emerge is a smaller flag leaf which curves to protect the emerging inflorescence. Scale leaves are first produced from the central meristem of developing suckers followed by narrow sword leaves and then broad leaves with wider laminae and finally full-sized leaves by 6 months.

13. www.iita.org A member of CGIAR consortium Morphology (Inflorescence) inflorescence is a complex spike with a stout peduncle on which flowers are arranged in nodal clusters. e ach node comprises two rows of flowers subtended by a bract which protects the young flowers. f lowers are predominantly unisexual, the plant monoecious and dichogamous proximal nodes bear female flowers (about 5-18) distal nodes contain male flowers tightly enclosed in bracts which form a conical structure (male bud). h ermaphrodite , or neutral flowers, may be present on the rachis (stalk between the female flowers and the male bud). peduncle elongates as flowers open in sequence.

14. www.iita.org A member of CGIAR consortium Question W hat do you understand by monoecious? dichogamous ? Is selfing possible in banana?

15. www.iita.org A member of CGIAR consortium Morphology (flowers) Male flowers have a smaller ovary, slender style, 5 stamens with long anthers that may or may not produce pollen. Female flowers have an inferior elongated trilocular ovary with 3 fused carpels bearing 6 petal (5 free and 1 fused) surrounding a thick style and non-functional staminodes Ovaries of female flowers later become the fruit or finger. Female flower Male flower

16. www.iita.org A member of CGIAR consortium Morphology (bunch) The ovaries of the female flowers develop into seedless fruits by pathenocarpy . Aborted ovules are seen as small brown flecks in centre of fruit. Nodal clusters of rows of female flowers is the hand and individual fruits developed from female flower is the finger . Number of hands per bunch and fingers per hand is determined at flower initiation by the no. of female flowers produced influenced by; genome group, crop cycle, temperature, plant vigour, level of management . Bunch position, appearance and shape are used to distinguish varieties. Weight of bunch is taken at harvest to determine yield. Other post-harvest traits – no. of hands, finger length, finger circumference, peel/pulp ratio, pulp color/texture, dry matter content, nutrient content.

17. www.iita.org A member of CGIAR consortium Question W hat are the major constraints to increased banana production?

18. www.iita.org A member of CGIAR consortium Propagation principle A well developed plantain plant has a corm with clumps of meristems of different ages and stages of development . Beside the main apical meristem, there are several lateral meristems found opposite the bases of the leaf sheaths When the apical meristem is destroyed lateral buds develop from lateral meristems on corms . Principle employed for macropropagation and field decapitation techniques for clean planting material production

19. www.iita.org A member of CGIAR consortium Micropropagation Sword suckers Explant preparation Shoot tip initiation Establishment and proliferation Multiple bud formation Rooted plantlets Shoot tip culture

20. www.iita.org A member of CGIAR consortium Micropropagation Micropropagation Over 1000 plantlets from a single plant in a year Disease-free planting material Uniform planting material; synchronized harvests Faster field establishment with higher yields Planting material can be obtained all year round Conventional propagation Only 5-10 suckers from single plant in a year Often infected planting material Non-uniform planting material; staggered harvests Slower field establishment with lower yields Limited availability of planting material

21. www.iita.org A member of CGIAR consortium Nematode Weevil Pests Diseases Biotic Constraints Black Sigatoka Bunchy top disease

22. www.iita.org A member of CGIAR consortium Breeding objectives Taste and consumer acceptability High and stable yields Disease and pest resistance (black sigatoka, nematode, weevil) Short stature Earliness

23. www.iita.org A member of CGIAR consortium Breeding bottlenecks Low reproductive fertility Parthenocarpy Triploidy Slow propagation Large space requirement (6m2/plant) Long generation time (about 2 years from seed to seed)

24. www.iita.org A member of CGIAR consortium Breeding scheme 3x landrace X 2x wild or improved 4x hybrid X 2x wild or improved 3x secondary triploid 2x doubling (oryzalin) Several black Sigatoka resistant PITA and BITA hybrids developed and are being distributed for testing.

25. www.iita.org A member of CGIAR consortium Breeding PITAs 3x landrace OL 2x wild PL 3x landrace BT 2x wild C4 4x hybrid 1658-4 (PITA 7) 2x hybrid 2829-62 3x hybrid – 23688-2 (PITA 21)

26. www.iita.org A member of CGIAR consortium Pollination - bagging Male parent Female parent

27. www.iita.org A member of CGIAR consortium Pollination male flowers female flowers 7.30-10.30am

28. www.iita.org A member of CGIAR consortium Question Why do we pollinate at 7.30 – 10.30 am?

29. www.iita.org A member of CGIAR consortium Ripening and seed extraction

30. www.iita.org A member of CGIAR consortium Embryo culture embryo extraction embryo germination bud proliferation root development acclimatization

31. www.iita.org A member of CGIAR consortium Evaluation Source: Pillay & Tenkouano 2011

32. www.iita.org A member of CGIAR consortium References and further r eading IPGRI-INIBAP/CIRAD Descriptors for banana (Musa spp .) 1996. Pillay M. and Tenkouano A. eds. Banana breeding: progress and challenges. CRC Press, 2011 . Robinson J. C. and Galán Saúco V. Bananas and plantains. Vol. 19. Cabi , 2010. Swennen R. Plantain cultivation under West Africa conditions: A reference manual. IITA, 1990 . Swennen R. and Ortiz R. Morphology and growth of plantain and banana. IITA, 1997 .

33. www.iita.org A member of CGIAR consortium Thank you.