Preface The previous two publications entitled “Breeding of Horticultural crops- Principles and Practices” authored by me was well received, accepted and proved very useful to the students, teachers and extension specialists of horticulture/agriculture science in our country. Through this message, I would like to thank all the stake holders who have prescribed/used this text book, without their support and encouragement, bringing out the third edition would not be possible. Further, subsequent to this first edition brought out in 2006, lot of new information on crop improvement aspects has become available in the last 10 years due to the intensive research and development work carried out in these crops by various ICAR institutes and many State Agricultural Universities in India. This has been duly included in the second edition brought out in 2014. This present third edition carefully covers all aspects of crop improvement made in our country besides in other countries especially in certain important horticulture crops. I do sincerely hope that this new edition will again prove much useful to the students, teachers, extension personnel of development departments dealing with this special group of horticultural crops.

Horticultural crops include the fruit crops, vegetables, spices, plantation crops, medicinal plants, aromatic plants, commercial flower crops and ornamental plants. Knowledge on the methods by which these reproduce is of primary importance from the standpoint of plant breeding. Besides, their annual or perennial nature also decides the methods of breeding to be adopted to get desired improvement. Two divisions of methods of reproduction commonly recognized are: 1. Asexual i.e. vegetative parts of the plants are utilized to produce new individuals. 2. Sexual i.e. gametic fusion, the resultant zygote develops into seed which is utilized to produce new individual. This group can be further placed in several sub divisions according to the mode of pollination. They are a. Naturally self pollinated crop - (e.g. tomato, pepper, brinjal) wherein cross pollination occurs less than 4 % only. b. Often cross pollinated crop- (e.g. chillies, bhendi) wherein though self pollination is more frequent, cross- pollination may occur so frequently that some methods of preventing cross pollination between varieties and strains of different genotypic constitution must be followed throughout the breeding programme. Common breeding methods can be applied to the above two groups, however, the parents chosen for breeding under often cross pollinated crop need to be selfed for few generations to select desirable, homozygous lines.

TROPICAL AND SUBTROPICAL FRUITS 2.1 Mango   Mango is considered to be an allopolyploid. The chromosome number is 2n =40. The polyembryonic seedlings of cv. Vellaikolumban, earlier reported to be 2n= 80 was later shown to be a diploid. In Canary Island, a putative tetraploid viz Gomera-1 has been identified. Floral biology Flower starts opening early in the morning from 4-7 a.m. and maximum flowers open between 9.30-10.30 a.m. and complete 11 a.m. Dehiscence of anthers takes place at 11.30 a.m. and it continues up to 3.45 p.m. The pollen grains are oval, or triangular or oblong. Stigma becomes receptive even 18 hours before flower opening. Mode of pollination is entomophily; nectar is present to attract the insects. The flowering duration is usually of short i.e. 2 to 3 weeks. The mango inflorescence or panicle bears mainly two types of flowers - male and perfect. The number of flowers per panicle varies between 1000 to 6000 depending upon the variety and climatic factors. The percentage of perfect flowers varies between 0.74 per cent in Rumani, 16.41 to 55.7 per cent in Neelum and up to 69.8 per cent in Langra.

3.1 Tomato Tomato (Lycopersicon esculentum) is an important vegetable crop. Its 2n= 24. Floral biology Flowers are borne in small forked racemose cyme. Anthesis starts at 6.30 a.m. and continues up to 11.00 a.m. Anther dehiscence is longitudinal. It occurs 1-2 days after opening of corolla. The stamen sheds its pollen when the style grows up through anther tube, thus self-pollination occurs. When the stigma protrudes above the anther tube, chances of cross pollination through bees increases. The optimum temperature for pollination is around 21°C.

Suggested Reference Books for Further Reading Chadha, K.L and O.P. Pareek, 1993. Advances in Horticulture, Fruit Crops- 1, Malhotra Publishing House, New Delhi. Chadha, K.L and G.Kalloo, 1993. Advances in Horticulture, Vegetable Crops- 5, Malhotra Publishing House, New Delhi. Chadha, K.L and G.G. Nayar, 1993. Advances in Horticulture, Tuber Crops- 8, Malhotra Publishing House, New Delhi. Chadha, K.L and P.Rethinam, 1993. Advances in Horticulture, Plantation Crops and Spices - 9, Malhotra Publishing House, New Delhi. Gupta, S. K. 2000. Plant Breeding: Theory and Techniques. Agrobios, Jodhpur. Kumar, N., JBM Md. Abdul Khader, P. Rengaswami and I. Iralappan, 1997. Introduction to Spices, Plantation Crops, Medicinal and Aromatic Plants. Oxford & IBH Publishing Co., New Delhi. Prem Singh Arya. 2000. Vegetable Breeding, Production and Seed Production. Kalyanai Publishers, New Delhi. Peter, K. V. 1998. Genetics and Breeding of Vegetables. ICAR, New Delhi. Singh, B. D. 2003.Plant Breeding, Kalyani Publishers, Ludhiana.