CROP IMPROVEMENT-INTRODUCTION, SELECTION & HYBRIDIZATION FOR APPLE, PEAR ,PEACH, PLUM & STRAWBERRY.

CROP IMPROVEMENT-INTRODUCTION, SELECTION & HYBRIDIZATION FOR APPLE, PEAR ,PEACH, PLUM & STRAWBERRY.

Crop improvement for apple, pear, peach, plum, and strawberry involves a multi-faceted approach encompassing introduction, selection, and hybridization. Introduction entails the acquisition of diverse germplasm from wild relatives or other sources to broaden genetic diversity. Selection focuses on identifying superior individuals within a population based on desirable traits such as yield, fruit quality, and disease resistance. Hybridization involves controlled crossbreeding to combine desirable traits from different parents, resulting in offspring with improved characteristics. Through systematic breeding programs integrating these methods, new varieties are developed, ensuring continuous enhancement of fruit quality, yield, and adaptability to changing environmental conditions.

1. A MASTER SEMINAR 0n CROP IMPROVEMENT-INTRODUCTION, SELECTION & HYBRIDIZATION FOR APPLE, PEAR ,PEACH, PLUM & STRAWBERRY. INDIRA GANDHI KRISHI VISHWAVIDYALAYA COLLEGE OF AGRICULTURE, RAIPUR SESSION: 2022-23 COURSE TITLE – MASTER SEMINAR COURSE CODE – FSC 591 COURSE CREDIT – 1(0+1 ) PRESENTED TO, Dr. Prabhakar Singh (Head and Professor) Dept. of Fruit Science PRESENTED BY, Damini Sendram M.Sc. (Prev.) year 2 nd Sem Clg.Id-20220258

2. Content INTRODUCTION 1. PLANT INTRODUCTION SELECTION HYBRIDISATION CASE STUDY CONCLUSION 6. 5. 4. 3. 2. CONCLUSION 7.

3. INTRODUCTION Fruit breeding refers to the purposeful genetic improvement of fruit crops through various techniques including selection, hybridization, mutation induction, and molecular techniques. Its origins trace to the domestication process in prehistory and antiquity, where useful species were choses and cultivated, and improved by continuous selection . ( Janick, 2011) Crop improvement refers to the genetic alteration of plants to satisfy human needs. The selection of naturally occurring variants is the basis of crop improvement. The conventional breeding methods of crop improvement includes- 1. Introduction 2. Selection 3. H ybridization

4. “ The acquisition of superior varieties by importing them from other area .” (Allard,1960) “The transposition of a genetic entity from an environment to which it is to one in which it is untried.” (Frankel,1955) “Transference of a genotype or a group of genotype of crop plants from the place of their cultivation into a new area where they were not being grown previously.” (Shripati et al., 2016) PLANT INTRODUCTION DEFINITION: -

5. To Serve as New Varieties . To Be Used in Crop Improvement. To Save the Crop from Diseases And Pests. For Scientific Studies & For Aesthetic Value. To Obtain An Entirely New Crop Plant. Objectives of Plant Introduction: -

6. Primary Introduction:- When the introduced variety is well suited/adapted to the new environment, it is released for commercial cultivation without any alteration in the original genotype. Secondary Introduction:- The introduced variety may be subjected to selection to isolate a superior variety or alternatively, it may be hybridized with local varieties to transfer one or few characters from this variety to the local ones. 1. Direct Introduction:- When new variety takes no time for establishment. Indirect Introduction:- When new variety takes some time for establishment. Exotic Variety:- Foreign variety directly recommended for commercial cultivation in new environment. Types of Introduction :- Based on adaptation: Based on utilization:

7. Procedure of Plant Introduction :- Introduction consists of the following six steps : Procurement :- Any individual or institution can introduce germplasm in India. But all the introductions must be routed through the NBPGR, New Delhi. Quarantine :- Quarantine means to keep materials in isolation to prevent the spread of diseases etc. All the introduced plant propagules are thoroughly inspected for contamination with weeds, diseases and insect pests. Cataloguing :- All the plant material which is introduced is given an entry number and information regarding name of the species, variety, place of origin, adaptation and its various characteristics are well documented. Further, they are classified into IC/IW/EC. Evaluation :- To assess the potential of new introductions, their performance is evaluated at different substations of the Bureau, Central Research Institute and SAU’s. Acclimatization:- Process that leads to the adaptation of a variety to a new or changed environment. Multiplication & Distribution:- Promising introductions or selections from the introductions may be increased and released as varieties after the necessary trials.

8. Procurement Cataloguing Evaluation Acclimatization Multiplication and Distribution Quarantine PROCEDURE:-

9. MERITS DEMERITS Merits & Demerits of Plant Introduction :- It provides entirely new crop plants. It provides superior varieties either directly or after selection & hybridization. Introduction helps to protect variability from genetic erosion. Hence helps in broadening the genetic base. It is very quick & economical method of crop improvement Plants may be introduced in new disease free areas to protect them from damage. Introduction of weeds, insects & pests as well as diseases along with introduced materials. Ex- Apple wooly aphid (1928) & Canker (1943) from Australia. Fire blight of Pear & Crown gall (1940) from England. San Jose Scale of Apple (1900) from Italy.

10. Fruit Crop Variety/ introduction Characteristics Picture Apple Vered (Israel) Low chilling cultivar, suited for lower hills and plain areas. It bears small to medium sized fruits (45g), conical flat, of 4.3 cm length and 4.5 cm diameter with 12 % TSS, light yellow with green skin splashed with red, sparingly soft flesh, ripens in middle of June, self fruitful. Delicious-II (USA) fruits (140g) with red splashed skin, ripening in middle of August; semi dwarf, open, spreading and well suited for high density planting; performed well in Shimla hills. Red Baron (USA) Heavy bearer, fruits medium size, yellow bright red colour, creamish yellow crisp, juicy and very sweet flesh Mollies Delicious (USA) Bears large fruits, red in colour, very sweet, crisp in taste with good keeping quality; matures in last week of July; has performed well at Solan in Himachal Pradesh. EXAMPLES OF INTRODUCTIONS IN TEMPERATE FRUIT CROPS

11. Golden Delicious (West Virginia, U.S.A) Fruit medium to large, oblong, skin golden yellow color and small dots scattered all over. Flesh creamy white, firm, crispy sweet with a blended acidity. The cultivar is a good pollinizer for all Delicious group Skyline Supreme (USA) Bears medium to large dark red fruits, very sweet, fruits with good keeping quality, mature in the first week of August; has wide adaptability from medium to high altitudes. Granny Smith (Sydney, Australia) Fruits green in colour, light yellowish on ripening. Flesh very firm, crisp, greenish yellow to whitish and sub-acidic in taste. Pear Bartlett (Europe) Popular commercial cultivar. Tree is prolific and regular bearer. Pulp is soft, juicy, sweet and scented but keeping quality is poor. Mid season variety, suitable for dessert purpose, drying and canning. Continued….

12. Fruit Crop Variety/ Introduction Characteristics Pictures Flemish Beauty (USA) Bears extra large fruit (172g), conical round in shape, very sweet, 14% TSS, greenish yellow skin with numerous tiny dots, white melting smooth, juicy. Max Red Bartlett (Italy) Bears large fruits (135g), pyriform, very sweet, 14% TSS, dark cranberry red, skin turning to an attractive bright red colour, white flesh, excellent in taste, medium keeping quality, fruits ripen in the first week of August. Devoe (USA) Bears pyriform, large light green fruits, flesh white, melting juicy, very sweet. Manning Elizabeth (USA) Bears small round yellowish green fruits, with a bright red blush at the blossom end; fruits are very sweet and excellent in taste, fruits ripen in the first week of July. Peach Stark Early Glo (USA) Early-type, with medium size fruit (79g), round deep yellow skin with bright red splashes, flesh is deep yellow, fine textured, juicy and very sweet, 12% TSS, with free stone, fruits ripen in the second week of June

13. Fruit Crop Variety/ Introduction Characteristics Pictures Flordasun (USA) Low chilling cultivar introduced at the PAU, Ludhiana which gave excellent performance in plains of Uttar Pradesh, Delhi and Rajasthan. Candor (USA) Promising cultivar for growing in Shimla hills, with medium size fruits (83g), round, TSS 11.9%, bright red blush over rich yellow ground colour, fine textured juicy, semi-free stone, fruits ripen in the second week of June. TA 170/ Pratap (USA) Early variety (7 days earlier than Flordasun), Flesh is yellow, firm with red coloration and better keeping quality. Plum Methley (Kenya) Promising variety, with medium size fruits (18.0g), very sweet, 20% TSS, fruits ripen in the middle of June. Kanto-5 (USA) Bud sport of Red Delicious, regular and heavy bearer, medium large shape.

14. Fruit Crop Variety/ Introduction Characteristics Pictures Santa Rosa (California, USA) A Japanese plum and it is self-fruitful, prolific bearing and has amber with red skin colour flesh. Satluj Purple It is self-unfruitful cultivar and requires Kala Amritsari as pollinizer planted in the ratio 85:25 in an acre. Epicarp develop crimson colour on ripening, thick skinned and mesocarp is yellow in colour. It ripens in early May and yield 35-40 Kg of fruit per tree. Frontier Rounded in shape, blooming time in first week of April and fruit matures in June.It is self fruitful variety.Yellow to orange flesh colour with grey purple fruit skin . President It is excellent dessert plum, being large in size. Purple with deep yellow flesh, juicy and sweet. It blooms early and require pollinizer. It is European type.

15. Fruit Crop Variety/ Introduction Characteristics Pictures Strawberry Chandler Conical fruit with glossy, shiny and attractive skin. Fruit is exceptionally high dessert quality with outstanding color and flavor. It is suitable for fresh market and processing. Highly resistant to viral diseases. Selva A day neutral cultivar, it has the capacity to produce off season. Fruits are large, skin and flesh firm with good dessert quality. Pajaro Grow well under summer conditions and tolerant to viruses. Fruit has good dessert and processing quality. Fruit is quite susceptible to physical damage caused by rain. Belrubi Fruit large, conical, skin bright red, less hollow at core, sweet, slightly sub-acid, average berry weight 15 g.

16. Fruit crops Introduced variety APPLE Spartan, Granny Smith, Ginger Gold, Early red one, Law Red Rome, Scarlet spur, Florina, Scarlet Gala, Summer Queen, Red Fuji, Red Spur, American Apirouge, Red Chief, Oregon spur, Well spur, Gala Mast, Gale Gala, PEAR Red Bartlett, Starkrimson, Max Red Bartlett, Red Sensation, Doyenne Burrah, ZH. Copeace, Abate, Carmen PLUM President, Early Italian, Red Plum, Frontier, Diurret , Friar, Queen, Anna, Nubina , Red Beaut , Grand Duke, Au-Rosa PEACH Crest Haven, Glohaven , Red Globe, Fantasia, Shizimu , Hakuto , Dawane , Flordasun, Flordared , Flordaprince , Earligrande , Sun red, Sun Gold, Nimla , July Elberta STRAWBERRY Addie, Bangalore, Belruby, Blackmore, Brighton, Camarosa , Chandler, Dana, Douglas, Elasta , Etna, Selva, Fenny, Gorella , Majestic, Robinson, Pajaro , Oso Grandy, Ofra , Missionary, Shasta, Steel master, Katrainsweet , Kimberley, Jutogh Special ACHIEVEMENTS OF INTRODUCTIONS IN TEMPERATE FRUIT CROPS CITH Annual Report 2013-14

17. SELECTION It can be defined as preservation of certain individual plants of desirable characters. The process which favors survival and further propagation of some plants having more desirable characters than others is called selection . In simplest form, selection means choosing plants of one’s choice. It is the basis of all crop improvement. I t is most common method of crop improvement among the cultivators. Practiced both in homozygous and heterozygous population. Efficacy/ Effectiveness of selection depend upon the presence of genetic variability in the base population & hereditary. INTRODUCTION: -

18. Types of Selection :- 1. Natural Selection: 2. Artificial Selection: This is a natural process. It operates in the nature without human interference. According to the Darwin’s principle  “Survival of the fittest”  plants which survive through the adversities of nature are preferred and the weaker ones are wiped out. So, natural selection favors these characters which are essential for survival of a species. It can be defined as to choose certain individual plants for the purpose of having better crop from a mixed population where the individuals differ in characters. There are 4 methods of artificial selection: ( i ) Mass selection (ii) Progeny selection (iii) Pure line selection (iv) Clonal selection,

19. ( i ) Mass Selection: It can be defined as selection of a number of phenotypically superior plants heads or seeds from the field population, harvesting and bulking their produce together for sowing the next year’s crop and repeating this process till desired characters are achieved. (ii) Progeny Selection: Progeny selection is the selection procedure in which superior plants are selected from a heterogeneous population on the basis of performance of their progenies. Progeny selection is commonly used in cross-pollinated and often cross-pollinated crops. (iii) Pure Line Selection: It can be defined as the process of isolating a desirable homozygous individual from the mixed population and multiplying the same without contamination to release as a new variety. The method of pure line selection has been developed from the classical work of W.L. Johanssen (1903), a Danish botanist , and is commonly used to improve the self- pollinated crops.

20. (iv)Clonal Selection:- Selection of desirable clones from the mixed population of vegetative propagated crops is known as clonal selection. OR Clonal selection is the selection and propagation of the desirable variations between the clones as well as within a clone. P rogeny of a single plant obtained by asexual reproduction is known as clone or all the vegetative progenies of a single plant are called a clone.   MERITS Effective method for genetic improvement of asexually propagated crops. Variety evolved by this method retains all the characters of the parental clone for several years. Varieties a re highly uniform like purelines . DEMERITS Utilizes the variability already present in the population. Genetic makeup cannot be improved by this method without hybridization. Varieties developed by clonal selection are highly prone to new type of diseases.

21. Fruit crops Variety Characteristics Picture Reference Apple Red Delicious Evolved as a chance seedling in IOWA, USA. (1972) Fleshy creamy white, tender, crisp, sweet, highly aromatic. Das et al.,2012 Kodaikanal Beauty (also known as- KKL-1), Developed as a result of clonal selection from Parlin’s Beauty. N.Kumar (2006): Breeding of Horticultural Crops: Principles & Practices CITH Lodh Apple 1 Clonal selection from Red delicious identified by CITH, Srinagar in 2012. Very Precocious, Regular bearing & Mid season blooming variety. Das et al., 2012 EXAMPLES OF SELECTIONS IN TEMPERATE FRUIT CROPS

22. Fruit crops Variety Characteristics Picture Reference Peach Sharbati Chance seedling selected at Saharanpur. The variety is characterized by the distinct pink tinge on the top. The fruit is juicy and mildly sweet. N.Kumar (2006) Breeding of Horticultural Crops: Principles & Practices CITH-P-1, CITH-P-2, CITH –P-3 Verma et al.,2015 Pant Peach-1 Pant Peach-1 is a chance seedling selection from population of cv. Sharbati .   Pear Verona-25 Clonal selection from Bartlett Ferrara Clonal selection from Bartlett Ravenna Clonal selection from Bartlett Punjab Nakh Hard pear selection from Patharnakh

23. Fruit crops Variety Characteristics Picture Reference Plum No.‘1725’ Clonal selection from “Mirabelle de Nancy” P 2778 Clonal selection from “Mirabelle de Mete” with high sugar content and typical aroma. Well suited for brandy production.

24. HYBRIDIZATION:- INTRODUCTION: - DEFINITION :- The mating or crossing of two plants or lines of dissimilar genotype is known as hybridization. OR The production of a hybrid by crossing two individuals of unlike genetical constitution is known as hybridization. Individual produced as a result of cross between two genetically different parents is known as hybrid. Hybridization is an important method of combining characters of different plants. Hybridization does not change genetic contents of organisms but it produces new combination of genes.

25. The main objective of hybridization is to create genetic variation. The aim of hybridization may be transfer of one or few qualitative characters. I mprovement of one or more quantitative characters. To exploit and utilize the hybrid varieties. Objectives of Hybridization: -

26. Hybridization may be of following types: ( i ) Intra-varietal hybridization: The crosses are made between the plants of the same variety. (ii) Inter-varietal or Intraspecific hybridization: The crosses are made between the plants belonging to two different varieties. (iii) Interspecific hybridization or intrageneric hybridization: The crosses are made between two different species of the same genus. iv) Introgressive/Intergeneric hybridization: Transfer of some genes from one species into the genome of the other species is known as introgressive or Intergeneric hybridization. The crosses between different species of the same genus or different genera of the same family are also known as distant hybridization or wide crossing. Such crosses are called distant crosses .

27. PROCEDURE:- SELECTION OF PLANTS SELFING OF PARENTS EMASCULATION BAGGING TAGGING CROSSING HARVESTING F1 GENERATION

28. Selection of Plant: It is referred to as choosing both the parental plants for the process, the plant must be healthy and can grow in the given condition are the two main prerequisites of the process. Homozygosity: Inducing homozygosity in the parental plants is important to establish the purity of lines, that is eliminating the unwanted traits. It is achieved by self-pollination or selfing of the parental plants over generation to achieve the result. Emasculation: It can be defined as the process of removal of male reproductive organs from the flower. It is mainly performed in bisexual flowers and is avoided in unisexual flowers. The removal of anthers or stamens (male reproductive organ) must be carried out without harming the ovum. It is done prior to pollen shading. There are the following methods that are used for emasculation, scissors Method, hot water treatment, alcohol treatment, and suction.

29. 4. Bagging: It can be defined as a method to cover the ovum of the flower. It is done to prevent cross-pollination of the flower by other pollen. The bags are made up of paper, butter paper, and vegetable parchment paper. 5.Tagging: It is the process of attaching a tag to the emasculated plant , which contains information about, the number of field records, date of emasculation, date of crossing, and name of the plant to which it is crossed. 6.Crossing: It is the process of artificial cross-pollination. In this process pollen from selected parents is placed on the stigma of the flower, to allow fertilization. 7.Harvestation: The seeds from this progeny are collected, and are stored with the original tag. 8.F1 Generation: The seeds give rise to the filial one generation which is then subjected to a selection of hybrids among it.

30. HYBRID VARIETIES OF APPLE Name Institute Method of Breeding/ parents Peculiar characters Lal Ambri SKUAST,Kashmir 1956 (Red Delicious x Ambri) High dessert quality with good keeping quality Ambred YSPUH&F, Nauni (Mashobra), HP (Red Delicious x Ambri 157) Fruits medium in size, bright red stripes over barium yellow ground. Keeping quality is good up to three months in air cooled storage. Ambstarking YSPUH&F, Nauni (Mashobra), HP (Starking Delicious x Ambri 81) Fruits medium in size, round, conical symmetrical and uniform in shape, currant red streaks over chrome yellow ground; dots numerous and conspicuousskin rough, smooth, flesh whitish firm, crisp, tough and juicy; keeping quality comparable with Starking Delicious. Sunehari SKUAST, Kashmir Ambri x Golden Delicious Nice yellow peels with crimson streaks. Crunchy and juicy with a sweet- acetous taste.

31. Ambroyal YSPUH&F, Nauni (Mashobra), HP (Starking Delicious x Ambri 84) Fruits medium in size, conical in shape; skin thin. Smooth, red streaks on yellow ground; flesh white, soft, sweet, juicy with good dessert quality. Storage quality is comparable with Starking Delicious Ambrich YSPUH&F, Nauni (Mashobra), HP (Richard x Ambri 15) Fruit medium size, round , conical in shape, symmetrical sides equal and uniform, skin thick; flesh whitish, firm crisp, sub acid aromatic and juicy with good dessert quality. Chaubattia Princess HETC, Ranikhet , UK. Early Shanburry x Red Delicious Fruit skin is thin and smooth with deep red streaks on pale background. Flesh is creamy white, crisp in texture, firm juicy and very sweet. TSS is 14 per cent and acidity 0.22 per cent. Early ripening variety.

32. Chaubattia Anupam HETC, Ranikhet , UK. Early Shanburry x Red Delicious Vigorous conical shape fruits. Swarnima HETC, Ranikhet , UK. Benoni x Red Delicious Early maturity Firdous SKUAST, Shalimar, Kashmir Ambri x Cox’s Orange Pippin Sweet with good shelf life. Shalimar Apple 1 SKUAST, Shalimar, Kashmir Sunhari x Prima Resistant to scab, red spider mites. Shirin SKUAST, Shalimar, Kashmir Lard Lambarchi x Melba x R-12740-7A Three way cross Scab resistant Akbar SKUAST, Shalimar, Kashmir Golden Delicious x Rome Beauty x Malus floribunda Three way cross. Scab resistant Verma et al., 2015

33. HYBRID VARIETIES OF PEAR Name Institute/Country Method of Breeding/ parents Peculiar characters Kieffer :   Europe P. communis x P. pyrifolia (Interspecific Hybridization) Moderately resistant to fire blight which is vigorous and very productive but self unfruitful Le-conte Pomology Dept. National Research Centre, Dokki P. communis x P. pyrifolia Grown in low and midhills because of low chilling required. Quit heavy bearing and small fruit. Magness USA Comice x Seckel (Hybridization) Plant very vigorous, spreading and male sterile. Fruits soft very juicy and almost free from grit cells. Punjab Beauty PUA, Punjab P. pyrifolia x P. Communis (Interspecific Hybridization) Fruit – medium, yellow with red blush . Flesh juicy sweet . Fruit matures in 3rd week of July. Punjab Nector PUA, Punjab P. pyrifolia x P. Communis (Hybridization) Fruit weight 136 g, TSS 14 % and 0.230 % acidity. The juice content 58 %. Matures in end of July. Punjab Gold PUA, Punjab P. pyrifolia x P. Communis (Hybridization) Fruit is uniform in size with 14.5 % TSS and 0.21 % acidity. Fruit weight 166g. Juice content 54 %.

34. Name Institute Method of Breeding/ parents Peculiar characters Saharanpur Prabhat Horticultural Research Institutes, Saharanpur, UP Sharbati x Flordasun (Intervarietal Hybridization) Fruits of this variety are attractive, sweet, maturing at least 4 days. Redhaven Michigan state University, at 1940 Hale Haven x Kalhaven (Hybridization) The most important and widely planted. Its outstanding characteristics are firm flesh, which excellent red color good size and heavy. Nemaguard   P.persica x P. davididasa (Hybridization) Used as root-knot nematode resistant rootstock. Candor Sandhills Research Station, North Carolina Red Haven x Early Red Free (Hybridization) The skin is bright red color, flesh yellow color. Excellent flavor and freestone. Dixigem   Admirral Dewey x St. Jonh (Hybridization) The fruit is round shape and skin color yellow. Freestone good in quality and texture. HYBRID VARIETIES OF PEACH

35. Interspecific hybrids in Prunus: 1.Plumcots/ apriplums – The name plumcot was created by Luther Burbank. Plumcot are hybrids between apricot & European plum. Genetically it has 50% traits of both apricot & plum. Plumcot varieties include Flavorosa , Flavour Royal, Crimson Sweet, Sweet Treat, Summer Punch, Tropical Sunrise and King Kong. 2. Pluots – hybrids produced from cross between plumcot & plum having 75% plum & 25% apricot traits. Pluots were developed in the late 20th century by Floyd Zaiger . Varities – Dapple Dandy, Flavour Prince, Flavour Queen, Flavorich , Red Ray etc. 3. Apriums – Plum-apricot hybrid that show more apricot traits (25% plum & 75% apricot). Developed in late 1980’s by Floyd Zaiger . Apriums are noted for their sweet taste due to their high content of Fructose & other complex sugars. Variety – Cot-N-Candy & Flavour Delight. 4. Nectaplum – hybrid of nectarines & plum developed by Floyd Zaiger . The fruits exterior has smooth skin closely resembling a nectarine. Variety – Spice Zee. 5. Peacotums : hybrid of peach, plum and apricot. Also, developed by Zaiger HYBRID VARIETIES OF PLUM

36. HYBRID VARIETIES OF STRAWBERRY Name Institute Method of Breeding/ parents Peculiar characters Arking Agricultural Experiment Station, USA Cardinal x Ark-5431 The plants are vigorous, productive and resistant to strawberry leaf spot, leaf scorch and powdery mildew. Honeoye   Vibrant x Holiday It is vigorous winter hardy plant. The fruits are large and attractive. Polka Netherland, 1977 Induka x Sivetta The fruits are fairly large, good quality and fruit size. They are suitable for fresh market. Segna sengana Originated in Humburg by Pro. Reinhold Markee x Sieger Good freezing quality

37. CONCLUSION Research on crop improvement in fruit crops is receiving considerable augmentation on account of the newly emerging production constraints due to pest, diseases, drought, salinity and climate change.

38. CITH Annual Report. 2011. Central Institute of Temperate Horticulture, Srinagar, J&K.FAO, 2011. Production – FAOSTAT. www.faostat.fao.org/site/339/default.aspx . Janick, J. 2011. History of fruit breeding. p. 1-7. In: Temperate Fruit Breeding. Fruit, Vegetable and Cereal Science and Biotechnology 5 (Special Issue 1). Janick, J. and J.N. Moore, (eds.), 1975. Advances in Fruit Breeding. Purdue University Press, West Lafayette, Indiana.