Breeding and Seed Production of Ornamental Crops (2+1)

Techniques of Breeding

Natural Crossing and Selection:

• Roses in nature are cross pollinated by insects, especially the bees.
• During the course of development, a huge amount of heterozygosity and different ploidy levels have been accumulated in roses.
• Seeds from naturally formed rose fruits may give a variable progeny, especially in the modern varieties, possessing a complex pedigree.
• Even without artificial crossing of hybridization, many new forms may be obtained from the segregating populations.
• A large number of modern rose varieties have been developed through selection.

Hybridization

• Hybridization of different species has been primarily responsible for the evolution of new groups of roses.
• Interspecific hybridization has played an important role in rose improvement.

Steps of hybridization

1. Emasculation should be done during the bud stage, just before they open out. This should be done carefully with a pair of finely pointed scissors or sharp knife, without damaging the stigma and to avoid self fertilization
2. The petals of the flowers selected as a male parent are removed and anthers are gently rubbed on stigma of the female parent with the help of soft camel brush.
3. Pollen may also be applied with the help of fingers of soft brush.
4. After crossing, a small polythene or butter paper bag is put over the crossed flower to protect it from any further natural cross pollination by insects.
5. The pollinated flowers are labeled indicating the parents of the cross as well as the date of crossing.
6. Rose fruits (hips) containing seeds, which takes 3-6 months to mature are harvested when they turn brownish red.

Mutation breeding:

• Recently many cultivars with novel flower colours have been evolved which are generally the results of artificial induction of mutations.
• These were produced as a result of treating the buds with X-rays, radio isotopes or various chemical mutagens.
• Several cultivars have been evolved through natural mutations or as bud sport of the existing cultivars.

Important mutants of rose developed in India

Sr. No.	Mutants	Parents	Mutagen	Centre whrere released
1.	'Pusa Christina'	Christian Dior	Gamma rays	IARI
2.	'Abhisarika'	Kiss of Fire	Gamma rays	IARI
3.	'Madhosh'	Gulzar	EMS (0.25% for 8 hours)	IARI
4.	'Su Kumare'	Queen Elizabeth	Gamma rays (3 Kr)	NBRI, Lucknow
5.	'Saroda'	Queen Elizabeth	Gamma rays	NBRI, Lucknow
6.	'Shavda'	Queen Elizabeth	Gamma rays	NBRI, Lucknow
7.	'Mrinalini striped'	Mrinalini H.T.	Gamma rays	-----
8.	'Mrinalini light pink mutant'	Mrinalini cv.	Gamma rays	-----