Emasculation and hybridization in rice

PLANT BREEDING

1. HYBRIDI Z A TION TECHNIQUE IN RICE

2. What is Hybridization? Hybrid H o m o z y g o us parents Genetically Dissimilar Crossing

3. Objectives To create variability To increase the yield of grain To increase grain quality To develop early maturity variety To develop disease resistant variety To develop insect and pest resistant variety To improve cooking characteristics

4. M A TERI A LS Rectified Spirit Needle Scissor Forceps James Clips Tags Polythene Bags Bamboo Sticks Conical Flask Threads

5. FLORAL BIOLOGY Terminal panicle which bears perfect flower. Sessile,bi-sexual,self pollinated flower. Flower having six stamens. Flower surrounded by lemma and palea. Gynocium consists of carpel-1,superior ovary and one chambered hypogynous. Most of the flowers bloom between 2-4 days. Blooming of the spikelets starts from panicle apex and proceeds downward. Pollen shed at the time of flower opening. Stigma remains receptive for 4-5 days. Pollen preservation possible for 24 hours at 54 degree F at 95% humidity Fertilization completes within 3 hours after pollination

6. Diag r ams of Floral Biology

7. STEPS IN HYBRIDIZATION

8. 1. Selection of female plants Insect and disease free healthy plant Selection of flowers expected to open by next morning Removal of immature and open flowers

9. 2. EMASCULATION Purpose of emasculation to prevent pollination Selection of panicles expected to open in the morning Selection of spikelets whose anther length about 60% Lemma and palea need to cut at a place 20% bellow from the tip Stamens need to remove one by one with sterized needle or forceps Best time : afternoon Bagging of emasculated flowers with polythene

10. EMASCULATION PROCESS

11. Diagrams of emasculation process

12. Mechanical e m asculat i on Mechanically prevented of pollen transfer Time saving, extensive,quite cheap vacuuming of anthers involves an aspirator and high speed suction of pollen from the anthers of flowers with a minimum damage to the stigma.

13. 3. POLLINATION Process of collecting anther and pollen grains of desired male parent and putting in the stigma at the emasculated flower of desired female parent Done in the next morning when the stigma is receptive Collection of yellow and turgid anthers from desired male plant and putting them in bright sunlight for 15 minutes Temporary removal of bag from female plants and pollination is done by dusting pollens over stigma surface of emasculated buds Sometimes whole anther is inserted inside the florets with the help of forceps

14. BAGGING Fixation of bamboo stick Top of the plants with bud inside the bag Two james clip through holes Exchanges of gases Stop the visit of insect

15. TAGGING After bagging tag bear following information: Cross combination (BR3 x BRRI dhan 29) Date of emasculation Date of pollination Numbers of buds pollinated Signature of the breeder

16. In agriculture, it is vitally important to maintain genetic diversity to obtain the health and longevity of a crop. As with other types of hybrids, hybrid rice typically displays heterosis Green Revolution popularized the use of conventional hybridization to increase yield by creating " high-yielding varieties ". Often the handful of hybridized breeds originated in developed countries and were further hybridized with local varieties in the rest of the developing world to create high yield strains resistant to local climate and diseases